Open Source Monorail

appengine/monorail/services/config_svc.py

Index: appengine/monorail/services/config_svc.py
diff --git a/appengine/monorail/services/config_svc.py b/appengine/monorail/services/config_svc.py
new file mode 100644
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+++ b/appengine/monorail/services/config_svc.py
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+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is govered by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+"""Classes and functions for persistence of issue tracker configuration.
+
+This module provides functions to get, update, create, and (in some
+cases) delete each type of business object.  It provides a logical
+persistence layer on top of an SQL database.
+
+Business objects are described in tracker_pb2.py and tracker_bizobj.py.
+"""
+
+import collections
+import logging
+
+from google.appengine.api import memcache
+
+import settings
+from framework import sql
+from proto import tracker_pb2
+from services import caches
+from tracker import tracker_bizobj
+
+
+TEMPLATE_TABLE_NAME = 'Template'
+TEMPLATE2LABEL_TABLE_NAME = 'Template2Label'
+TEMPLATE2ADMIN_TABLE_NAME = 'Template2Admin'
+TEMPLATE2COMPONENT_TABLE_NAME = 'Template2Component'
+TEMPLATE2FIELDVALUE_TABLE_NAME = 'Template2FieldValue'
+PROJECTISSUECONFIG_TABLE_NAME = 'ProjectIssueConfig'
+LABELDEF_TABLE_NAME = 'LabelDef'
+FIELDDEF_TABLE_NAME = 'FieldDef'
+FIELDDEF2ADMIN_TABLE_NAME = 'FieldDef2Admin'
+COMPONENTDEF_TABLE_NAME = 'ComponentDef'
+COMPONENT2ADMIN_TABLE_NAME = 'Component2Admin'
+COMPONENT2CC_TABLE_NAME = 'Component2Cc'
+STATUSDEF_TABLE_NAME = 'StatusDef'
+
+TEMPLATE_COLS = [
+    'id', 'project_id', 'name', 'content', 'summary', 'summary_must_be_edited',
+    'owner_id', 'status', 'members_only', 'owner_defaults_to_member',
+    'component_required']
+TEMPLATE2LABEL_COLS = ['template_id', 'label']
+TEMPLATE2COMPONENT_COLS = ['template_id', 'component_id']
+TEMPLATE2ADMIN_COLS = ['template_id', 'admin_id']
+TEMPLATE2FIELDVALUE_COLS = [
+    'template_id', 'field_id', 'int_value', 'str_value', 'user_id']
+PROJECTISSUECONFIG_COLS = [
+    'project_id', 'statuses_offer_merge', 'exclusive_label_prefixes',
+    'default_template_for_developers', 'default_template_for_users',
+    'default_col_spec', 'default_sort_spec', 'default_x_attr',
+    'default_y_attr', 'custom_issue_entry_url']
+STATUSDEF_COLS = [
+    'id', 'project_id', 'rank', 'status', 'means_open', 'docstring',
+    'deprecated']
+LABELDEF_COLS = [
+    'id', 'project_id', 'rank', 'label', 'docstring', 'deprecated']
+FIELDDEF_COLS = [
+    'id', 'project_id', 'rank', 'field_name', 'field_type', 'applicable_type',
+    'applicable_predicate', 'is_required', 'is_multivalued',
+    'min_value', 'max_value', 'regex', 'needs_member', 'needs_perm',
+    'grants_perm', 'notify_on', 'docstring', 'is_deleted']
+FIELDDEF2ADMIN_COLS = ['field_id', 'admin_id']
+COMPONENTDEF_COLS = ['id', 'project_id', 'path', 'docstring', 'deprecated',
+                     'created', 'creator_id', 'modified', 'modifier_id']
+COMPONENT2ADMIN_COLS = ['component_id', 'admin_id']
+COMPONENT2CC_COLS = ['component_id', 'cc_id']
+
+NOTIFY_ON_ENUM = ['never', 'any_comment']
+
+
+class LabelRowTwoLevelCache(caches.AbstractTwoLevelCache):
+  """Class to manage RAM and memcache for label rows.
+
+  Label rows exist for every label used in a project, even those labels
+  that were added to issues in an ad hoc way without being defined in the
+  config ahead of time.
+  """
+
+  def __init__(self, cache_manager, config_service):
+    super(LabelRowTwoLevelCache, self).__init__(
+        cache_manager, 'project', 'label_rows:', None)
+    self.config_service = config_service
+
+  def _DeserializeLabelRows(self, label_def_rows):
+    """Convert DB result rows into a dict {project_id: [row, ...]}."""
+    result_dict = collections.defaultdict(list)
+    for label_id, project_id, rank, label, docstr, deprecated in label_def_rows:
+      result_dict[project_id].append(
+          (label_id, project_id, rank, label, docstr, deprecated))
+
+    return result_dict
+
+  def FetchItems(self, cnxn, keys):
+    """On RAM and memcache miss, hit the database."""
+    label_def_rows = self.config_service.labeldef_tbl.Select(
+        cnxn, cols=LABELDEF_COLS, project_id=keys,
+        order_by=[('rank DESC', []), ('label DESC', [])])
+    label_rows_dict = self._DeserializeLabelRows(label_def_rows)
+
+    # Make sure that every requested project is represented in the result
+    for project_id in keys:
+      label_rows_dict.setdefault(project_id, [])
+
+    return label_rows_dict
+
+
+class StatusRowTwoLevelCache(caches.AbstractTwoLevelCache):
+  """Class to manage RAM and memcache for status rows."""
+
+  def __init__(self, cache_manager, config_service):
+    super(StatusRowTwoLevelCache, self).__init__(
+        cache_manager, 'project', 'status_rows:', None)
+    self.config_service = config_service
+
+  def _DeserializeStatusRows(self, def_rows):
+    """Convert status definition rows into {project_id: [row, ...]}."""
+    result_dict = collections.defaultdict(list)
+    for (status_id, project_id, rank, status,
+         means_open, docstr, deprecated) in def_rows:
+      result_dict[project_id].append(
+          (status_id, project_id, rank, status, means_open, docstr, deprecated))
+
+    return result_dict
+
+  def FetchItems(self, cnxn, keys):
+    """On cache miss, get status definition rows from the DB."""
+    status_def_rows = self.config_service.statusdef_tbl.Select(
+        cnxn, cols=STATUSDEF_COLS, project_id=keys,
+        order_by=[('rank DESC', []), ('status DESC', [])])
+    status_rows_dict = self._DeserializeStatusRows(status_def_rows)
+
+    # Make sure that every requested project is represented in the result
+    for project_id in keys:
+      status_rows_dict.setdefault(project_id, [])
+
+    return status_rows_dict
+
+
+class FieldRowTwoLevelCache(caches.AbstractTwoLevelCache):
+  """Class to manage RAM and memcache for field rows.
+
+  Field rows exist for every field used in a project, since they cannot be
+  created through ad-hoc means.
+  """
+
+  def __init__(self, cache_manager, config_service):
+    super(FieldRowTwoLevelCache, self).__init__(
+        cache_manager, 'project', 'field_rows:', None)
+    self.config_service = config_service
+
+  def _DeserializeFieldRows(self, field_def_rows):
+    """Convert DB result rows into a dict {project_id: [row, ...]}."""
+    result_dict = collections.defaultdict(list)
+    # TODO(agable): Actually process the rest of the items.
+    for (field_id, project_id, rank, field_name, _field_type, _applicable_type,
+         _applicable_predicate, _is_required, _is_multivalued, _min_value,
+         _max_value, _regex, _needs_member, _needs_perm, _grants_perm,
+         _notify_on, docstring, _is_deleted) in field_def_rows:
+      result_dict[project_id].append(
+          (field_id, project_id, rank, field_name, docstring))
+
+    return result_dict
+
+  def FetchItems(self, cnxn, keys):
+    """On RAM and memcache miss, hit the database."""
+    field_def_rows = self.config_service.fielddef_tbl.Select(
+        cnxn, cols=FIELDDEF_COLS, project_id=keys,
+        order_by=[('rank DESC', []), ('field_name DESC', [])])
+    field_rows_dict = self._DeserializeFieldRows(field_def_rows)
+
+    # Make sure that every requested project is represented in the result
+    for project_id in keys:
+      field_rows_dict.setdefault(project_id, [])
+
+    return field_rows_dict
+
+
+class ConfigTwoLevelCache(caches.AbstractTwoLevelCache):
+  """Class to manage RAM and memcache for IssueProjectConfig PBs."""
+
+  def __init__(self, cache_manager, config_service):
+    super(ConfigTwoLevelCache, self).__init__(
+        cache_manager, 'project', 'config:', tracker_pb2.ProjectIssueConfig)
+    self.config_service = config_service
+
+  def _UnpackProjectIssueConfig(self, config_row):
+    """Partially construct a config object using info from a DB row."""
+    (project_id, statuses_offer_merge, exclusive_label_prefixes,
+     default_template_for_developers, default_template_for_users,
+     default_col_spec, default_sort_spec, default_x_attr, default_y_attr,
+     custom_issue_entry_url) = config_row
+    config = tracker_pb2.ProjectIssueConfig()
+    config.project_id = project_id
+    config.statuses_offer_merge.extend(statuses_offer_merge.split())
+    config.exclusive_label_prefixes.extend(exclusive_label_prefixes.split())
+    config.default_template_for_developers = default_template_for_developers
+    config.default_template_for_users = default_template_for_users
+    config.default_col_spec = default_col_spec
+    config.default_sort_spec = default_sort_spec
+    config.default_x_attr = default_x_attr
+    config.default_y_attr = default_y_attr
+    if custom_issue_entry_url is not None:
+      config.custom_issue_entry_url = custom_issue_entry_url
+
+    return config
+
+  def _UnpackTemplate(self, template_row):
+    """Partially construct a template object using info from a DB row."""
+    (template_id, project_id, name, content, summary,
+     summary_must_be_edited, owner_id, status,
+     members_only, owner_defaults_to_member, component_required) = template_row
+    template = tracker_pb2.TemplateDef()
+    template.template_id = template_id
+    template.name = name
+    template.content = content
+    template.summary = summary
+    template.summary_must_be_edited = bool(
+        summary_must_be_edited)
+    template.owner_id = owner_id or 0
+    template.status = status
+    template.members_only = bool(members_only)
+    template.owner_defaults_to_member = bool(owner_defaults_to_member)
+    template.component_required = bool(component_required)
+
+    return template, project_id
+
+  def _UnpackFieldDef(self, fielddef_row):
+    """Partially construct a FieldDef object using info from a DB row."""
+    (field_id, project_id, _rank, field_name, field_type,
+     applic_type, applic_pred, is_required, is_multivalued,
+     min_value, max_value, regex, needs_member, needs_perm,
+     grants_perm, notify_on_str, docstring, is_deleted) = fielddef_row
+    if notify_on_str == 'any_comment':
+      notify_on = tracker_pb2.NotifyTriggers.ANY_COMMENT
+    else:
+      notify_on = tracker_pb2.NotifyTriggers.NEVER
+
+    return tracker_bizobj.MakeFieldDef(
+        field_id, project_id, field_name,
+        tracker_pb2.FieldTypes(field_type.upper()), applic_type, applic_pred,
+        is_required, is_multivalued, min_value, max_value, regex,
+        needs_member, needs_perm, grants_perm, notify_on, docstring,
+        is_deleted)
+
+  def _UnpackComponentDef(
+      self, cd_row, component2admin_rows, component2cc_rows):
+    """Partially construct a FieldDef object using info from a DB row."""
+    (component_id, project_id, path, docstring, deprecated, created,
+     creator_id, modified, modifier_id) = cd_row
+    cd = tracker_bizobj.MakeComponentDef(
+        component_id, project_id, path, docstring, deprecated,
+        [admin_id for comp_id, admin_id in component2admin_rows
+         if comp_id == component_id],
+        [cc_id for comp_id, cc_id in component2cc_rows
+         if comp_id == component_id],
+        created, creator_id, modified, modifier_id)
+
+    return cd
+
+  def _DeserializeIssueConfigs(
+      self, config_rows, template_rows, template2label_rows,
+      template2component_rows, template2admin_rows, template2fieldvalue_rows,
+      statusdef_rows, labeldef_rows, fielddef_rows, fielddef2admin_rows,
+      componentdef_rows, component2admin_rows, component2cc_rows):
+    """Convert the given row tuples into a dict of ProjectIssueConfig PBs."""
+    result_dict = {}
+    template_dict = {}
+    fielddef_dict = {}
+
+    for config_row in config_rows:
+      config = self._UnpackProjectIssueConfig(config_row)
+      result_dict[config.project_id] = config
+
+    for template_row in template_rows:
+      template, project_id = self._UnpackTemplate(template_row)
+      if project_id in result_dict:
+        result_dict[project_id].templates.append(template)
+        template_dict[template.template_id] = template
+
+    for template2label_row in template2label_rows:
+      template_id, label = template2label_row
+      template = template_dict.get(template_id)
+      if template:
+        template.labels.append(label)
+
+    for template2component_row in template2component_rows:
+      template_id, component_id = template2component_row
+      template = template_dict.get(template_id)
+      if template:
+        template.component_ids.append(component_id)
+
+    for template2admin_row in template2admin_rows:
+      template_id, admin_id = template2admin_row
+      template = template_dict.get(template_id)
+      if template:
+        template.admin_ids.append(admin_id)
+
+    for fv_row in template2fieldvalue_rows:
+      template_id, field_id, int_value, str_value, user_id = fv_row
+      fv = tracker_bizobj.MakeFieldValue(
+          field_id, int_value, str_value, user_id, False)
+      template = template_dict.get(template_id)
+      if template:
+        template.field_values.append(fv)
+
+    for statusdef_row in statusdef_rows:
+      (_, project_id, _rank, status,
+       means_open, docstring, deprecated) = statusdef_row
+      if project_id in result_dict:
+        wks = tracker_pb2.StatusDef(
+            status=status, means_open=bool(means_open),
+            status_docstring=docstring or '', deprecated=bool(deprecated))
+        result_dict[project_id].well_known_statuses.append(wks)
+
+    for labeldef_row in labeldef_rows:
+      _, project_id, _rank, label, docstring, deprecated = labeldef_row
+      if project_id in result_dict:
+        wkl = tracker_pb2.LabelDef(
+            label=label, label_docstring=docstring or '',
+            deprecated=bool(deprecated))
+        result_dict[project_id].well_known_labels.append(wkl)
+
+    for fd_row in fielddef_rows:
+      fd = self._UnpackFieldDef(fd_row)
+      result_dict[fd.project_id].field_defs.append(fd)
+      fielddef_dict[fd.field_id] = fd
+
+    for fd2admin_row in fielddef2admin_rows:
+      field_id, admin_id = fd2admin_row
+      fd = fielddef_dict.get(field_id)
+      if fd:
+        fd.admin_ids.append(admin_id)
+
+    for cd_row in componentdef_rows:
+      cd = self._UnpackComponentDef(
+          cd_row, component2admin_rows, component2cc_rows)
+      result_dict[cd.project_id].component_defs.append(cd)
+
+    return result_dict
+
+  def _FetchConfigs(self, cnxn, project_ids):
+    """On RAM and memcache miss, hit the database."""
+    config_rows = self.config_service.projectissueconfig_tbl.Select(
+        cnxn, cols=PROJECTISSUECONFIG_COLS, project_id=project_ids)
+    template_rows = self.config_service.template_tbl.Select(
+        cnxn, cols=TEMPLATE_COLS, project_id=project_ids,
+        order_by=[('name', [])])
+    template_ids = [row[0] for row in template_rows]
+    template2label_rows = self.config_service.template2label_tbl.Select(
+        cnxn, cols=TEMPLATE2LABEL_COLS, template_id=template_ids)
+    template2component_rows = self.config_service.template2component_tbl.Select(
+        cnxn, cols=TEMPLATE2COMPONENT_COLS, template_id=template_ids)
+    template2admin_rows = self.config_service.template2admin_tbl.Select(
+        cnxn, cols=TEMPLATE2ADMIN_COLS, template_id=template_ids)
+    template2fv_rows = self.config_service.template2fieldvalue_tbl.Select(
+        cnxn, cols=TEMPLATE2FIELDVALUE_COLS, template_id=template_ids)
+    logging.info('t2fv is %r', template2fv_rows)
+    statusdef_rows = self.config_service.statusdef_tbl.Select(
+        cnxn, cols=STATUSDEF_COLS, project_id=project_ids,
+        where=[('rank IS NOT NULL', [])], order_by=[('rank', [])])
+    labeldef_rows = self.config_service.labeldef_tbl.Select(
+        cnxn, cols=LABELDEF_COLS, project_id=project_ids,
+        where=[('rank IS NOT NULL', [])], order_by=[('rank', [])])
+    # TODO(jrobbins): For now, sort by field name, but someday allow admins
+    # to adjust the rank to group and order field definitions logically.
+    fielddef_rows = self.config_service.fielddef_tbl.Select(
+        cnxn, cols=FIELDDEF_COLS, project_id=project_ids,
+        order_by=[('field_name', [])])
+    field_ids = [row[0] for row in fielddef_rows]
+    fielddef2admin_rows = self.config_service.fielddef2admin_tbl.Select(
+        cnxn, cols=FIELDDEF2ADMIN_COLS, field_id=field_ids)
+    componentdef_rows = self.config_service.componentdef_tbl.Select(
+        cnxn, cols=COMPONENTDEF_COLS, project_id=project_ids,
+        order_by=[('LOWER(path)', [])])
+    component_ids = [cd_row[0] for cd_row in componentdef_rows]
+    component2admin_rows = self.config_service.component2admin_tbl.Select(
+        cnxn, cols=COMPONENT2ADMIN_COLS, component_id=component_ids)
+    component2cc_rows = self.config_service.component2cc_tbl.Select(
+        cnxn, cols=COMPONENT2CC_COLS, component_id=component_ids)
+
+    retrieved_dict = self._DeserializeIssueConfigs(
+        config_rows, template_rows, template2label_rows,
+        template2component_rows, template2admin_rows,
+        template2fv_rows, statusdef_rows, labeldef_rows,
+        fielddef_rows, fielddef2admin_rows, componentdef_rows,
+        component2admin_rows, component2cc_rows)
+    return retrieved_dict
+
+  def FetchItems(self, cnxn, keys):
+    """On RAM and memcache miss, hit the database."""
+    retrieved_dict = self._FetchConfigs(cnxn, keys)
+
+    # Any projects which don't have stored configs should use a default
+    # config instead.
+    for project_id in keys:
+      if project_id not in retrieved_dict:
+        config = tracker_bizobj.MakeDefaultProjectIssueConfig(project_id)
+        retrieved_dict[project_id] = config
+
+    return retrieved_dict
+
+
+class ConfigService(object):
+  """The persistence layer for Monorail's issue tracker configuration data."""
+
+  def __init__(self, cache_manager):
+    """Initialize this object so that it is ready to use.
+
+    Args:
+      cache_manager: manages local caches with distributed invalidation.
+    """
+    self.template_tbl = sql.SQLTableManager(TEMPLATE_TABLE_NAME)
+    self.template2label_tbl = sql.SQLTableManager(TEMPLATE2LABEL_TABLE_NAME)
+    self.template2component_tbl = sql.SQLTableManager(
+        TEMPLATE2COMPONENT_TABLE_NAME)
+    self.template2admin_tbl = sql.SQLTableManager(TEMPLATE2ADMIN_TABLE_NAME)
+    self.template2fieldvalue_tbl = sql.SQLTableManager(
+        TEMPLATE2FIELDVALUE_TABLE_NAME)
+    self.projectissueconfig_tbl = sql.SQLTableManager(
+        PROJECTISSUECONFIG_TABLE_NAME)
+    self.statusdef_tbl = sql.SQLTableManager(STATUSDEF_TABLE_NAME)
+    self.labeldef_tbl = sql.SQLTableManager(LABELDEF_TABLE_NAME)
+    self.fielddef_tbl = sql.SQLTableManager(FIELDDEF_TABLE_NAME)
+    self.fielddef2admin_tbl = sql.SQLTableManager(FIELDDEF2ADMIN_TABLE_NAME)
+    self.componentdef_tbl = sql.SQLTableManager(COMPONENTDEF_TABLE_NAME)
+    self.component2admin_tbl = sql.SQLTableManager(COMPONENT2ADMIN_TABLE_NAME)
+    self.component2cc_tbl = sql.SQLTableManager(COMPONENT2CC_TABLE_NAME)
+
+    self.config_2lc = ConfigTwoLevelCache(cache_manager, self)
+    self.label_row_2lc = LabelRowTwoLevelCache(cache_manager, self)
+    self.label_cache = cache_manager.MakeCache('project')
+    self.status_row_2lc = StatusRowTwoLevelCache(cache_manager, self)
+    self.status_cache = cache_manager.MakeCache('project')
+    self.field_row_2lc = FieldRowTwoLevelCache(cache_manager, self)
+    self.field_cache = cache_manager.MakeCache('project')
+
+  ### Label lookups
+
+  def GetLabelDefRows(self, cnxn, project_id):
+    """Get SQL result rows for all labels used in the specified project."""
+    pids_to_label_rows, misses = self.label_row_2lc.GetAll(cnxn, [project_id])
+    assert not misses
+    return pids_to_label_rows[project_id]
+
+  def GetLabelDefRowsAnyProject(self, cnxn, where=None):
+    """Get all LabelDef rows for the whole site. Used in whole-site search."""
+    # TODO(jrobbins): maybe add caching for these too.
+    label_def_rows = self.labeldef_tbl.Select(
+        cnxn, cols=LABELDEF_COLS, where=where,
+        order_by=[('rank DESC', []), ('label DESC', [])])
+    return label_def_rows
+
+  def _DeserializeLabels(self, def_rows):
+    """Convert label defs into bi-directional mappings of names and IDs."""
+    label_id_to_name = {
+        label_id: label for
+        label_id, _pid, _rank, label, _doc, _deprecated
+        in def_rows}
+    label_name_to_id = {
+        label.lower(): label_id
+        for label_id, label in label_id_to_name.iteritems()}
+
+    return label_id_to_name, label_name_to_id
+
+  def _EnsureLabelCacheEntry(self, cnxn, project_id):
+    """Make sure that self.label_cache has an entry for project_id."""
+    if not self.label_cache.HasItem(project_id):
+      def_rows = self.GetLabelDefRows(cnxn, project_id)
+      self.label_cache.CacheItem(project_id, self._DeserializeLabels(def_rows))
+
+  def LookupLabel(self, cnxn, project_id, label_id):
+    """Lookup a label string given the label_id.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the project where the label is defined or used.
+      label_id: int label ID.
+
+    Returns:
+      Label name string for the given label_id, or None.
+    """
+    self._EnsureLabelCacheEntry(cnxn, project_id)
+    label_id_to_name, _label_name_to_id = self.label_cache.GetItem(
+        project_id)
+    return label_id_to_name.get(label_id)
+
+  def LookupLabelID(self, cnxn, project_id, label, autocreate=True):
+    """Look up a label ID, optionally interning it.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the project where the statuses are defined.
+      label: label string.
+      autocreate: if not already in the DB, store it and generate a new ID.
+
+    Returns:
+      The label ID for the given label string.
+    """
+    self._EnsureLabelCacheEntry(cnxn, project_id)
+    _label_id_to_name, label_name_to_id = self.label_cache.GetItem(
+        project_id)
+    if label.lower() in label_name_to_id:
+      return label_name_to_id[label.lower()]
+
+    if autocreate:
+      logging.info('No label %r is known in project %d, so intern it.',
+                   label, project_id)
+      label_id = self.labeldef_tbl.InsertRow(
+          cnxn, project_id=project_id, label=label)
+      self.label_row_2lc.InvalidateKeys(cnxn, [project_id])
+      self.label_cache.Invalidate(cnxn, project_id)
+      return label_id
+
+    return None  # It was not found and we don't want to create it.
+
+  def LookupLabelIDs(self, cnxn, project_id, labels, autocreate=False):
+    """Look up several label IDs.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the project where the statuses are defined.
+      labels: list of label strings.
+      autocreate: if not already in the DB, store it and generate a new ID.
+
+    Returns:
+      Returns a list of int label IDs for the given label strings.
+    """
+    result = []
+    for lab in labels:
+      label_id = self.LookupLabelID(
+          cnxn, project_id, lab, autocreate=autocreate)
+      if label_id is not None:
+        result.append(label_id)
+
+    return result
+
+  def LookupIDsOfLabelsMatching(self, cnxn, project_id, regex):
+    """Look up the IDs of all labels in a project that match the regex.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the project where the statuses are defined.
+      regex: regular expression object to match against the label strings.
+
+    Returns:
+      List of label IDs for labels that match the regex.
+    """
+    self._EnsureLabelCacheEntry(cnxn, project_id)
+    label_id_to_name, _label_name_to_id = self.label_cache.GetItem(
+        project_id)
+    result = [label_id for label_id, label in label_id_to_name.iteritems()
+              if regex.match(label)]
+
+    return result
+
+  def LookupLabelIDsAnyProject(self, cnxn, label):
+    """Return the IDs of labels with the given name in any project.
+
+    Args:
+      cnxn: connection to SQL database.
+      label: string label to look up.  Case sensitive.
+
+    Returns:
+      A list of int label IDs of all labels matching the given string.
+    """
+    # TODO(jrobbins): maybe add caching for these too.
+    label_id_rows = self.labeldef_tbl.Select(
+        cnxn, cols=['id'], label=label)
+    label_ids = [row[0] for row in label_id_rows]
+    return label_ids
+
+  def LookupIDsOfLabelsMatchingAnyProject(self, cnxn, regex):
+    """Return the IDs of matching labels in any project."""
+    label_rows = self.labeldef_tbl.Select(
+        cnxn, cols=['id', 'label'])
+    matching_ids = [
+        label_id for label_id, label in label_rows if regex.match(label)]
+    return matching_ids
+
+  ### Status lookups
+
+  def GetStatusDefRows(self, cnxn, project_id):
+    """Return a list of status definition rows for the specified project."""
+    pids_to_status_rows, misses = self.status_row_2lc.GetAll(
+        cnxn, [project_id])
+    assert not misses
+    return pids_to_status_rows[project_id]
+
+  def GetStatusDefRowsAnyProject(self, cnxn):
+    """Return all status definition rows on the whole site."""
+    # TODO(jrobbins): maybe add caching for these too.
+    status_def_rows = self.statusdef_tbl.Select(
+        cnxn, cols=STATUSDEF_COLS,
+        order_by=[('rank DESC', []), ('status DESC', [])])
+    return status_def_rows
+
+  def _DeserializeStatuses(self, def_rows):
+    """Convert status defs into bi-directional mappings of names and IDs."""
+    status_id_to_name = {
+        status_id: status
+        for (status_id, _pid, _rank, status, _means_open,
+             _doc, _deprecated) in def_rows}
+    status_name_to_id = {
+        status.lower(): status_id
+        for status_id, status in status_id_to_name.iteritems()}
+    closed_status_ids = [
+        status_id
+        for (status_id, _pid, _rank, _status, means_open,
+             _doc, _deprecated) in def_rows
+        if means_open == 0]  # Only 0 means closed. NULL/None means open.
+
+    return status_id_to_name, status_name_to_id, closed_status_ids
+
+  def _EnsureStatusCacheEntry(self, cnxn, project_id):
+    """Make sure that self.status_cache has an entry for project_id."""
+    if not self.status_cache.HasItem(project_id):
+      def_rows = self.GetStatusDefRows(cnxn, project_id)
+      self.status_cache.CacheItem(
+          project_id, self._DeserializeStatuses(def_rows))
+
+  def LookupStatus(self, cnxn, project_id, status_id):
+    """Look up a status string for the given status ID.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the project where the statuses are defined.
+      status_id: int ID of the status value.
+
+    Returns:
+      A status string, or None.
+    """
+    if status_id == 0:
+      return ''
+
+    self._EnsureStatusCacheEntry(cnxn, project_id)
+    (status_id_to_name, _status_name_to_id,
+     _closed_status_ids) = self.status_cache.GetItem(project_id)
+
+    return status_id_to_name.get(status_id)
+
+  def LookupStatusID(self, cnxn, project_id, status, autocreate=True):
+    """Look up a status ID for the given status string.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the project where the statuses are defined.
+      status: status string.
+      autocreate: if not already in the DB, store it and generate a new ID.
+
+    Returns:
+      The status ID for the given status string, or None.
+    """
+    if not status:
+      return None
+
+    self._EnsureStatusCacheEntry(cnxn, project_id)
+    (_status_id_to_name, status_name_to_id,
+     _closed_status_ids) = self.status_cache.GetItem(project_id)
+    if status.lower() in status_name_to_id:
+      return status_name_to_id[status.lower()]
+
+    if autocreate:
+      logging.info('No status %r is known in project %d, so intern it.',
+                   status, project_id)
+      status_id = self.statusdef_tbl.InsertRow(
+          cnxn, project_id=project_id, status=status)
+      self.status_row_2lc.InvalidateKeys(cnxn, [project_id])
+      self.status_cache.Invalidate(cnxn, project_id)
+      return status_id
+
+    return None  # It was not found and we don't want to create it.
+
+  def LookupStatusIDs(self, cnxn, project_id, statuses):
+    """Look up several status IDs for the given status strings.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the project where the statuses are defined.
+      statuses: list of status strings.
+
+    Returns:
+      A list of int status IDs.
+    """
+    result = []
+    for stat in statuses:
+      status_id = self.LookupStatusID(cnxn, project_id, stat, autocreate=False)
+      if status_id:
+        result.append(status_id)
+
+    return result
+
+  def LookupClosedStatusIDs(self, cnxn, project_id):
+    """Return the IDs of closed statuses defined in the given project."""
+    self._EnsureStatusCacheEntry(cnxn, project_id)
+    (_status_id_to_name, _status_name_to_id,
+     closed_status_ids) = self.status_cache.GetItem(project_id)
+
+    return closed_status_ids
+
+  def LookupClosedStatusIDsAnyProject(self, cnxn):
+    """Return the IDs of closed statuses defined in any project."""
+    status_id_rows = self.statusdef_tbl.Select(
+        cnxn, cols=['id'], means_open=False)
+    status_ids = [row[0] for row in status_id_rows]
+    return status_ids
+
+  def LookupStatusIDsAnyProject(self, cnxn, status):
+    """Return the IDs of statues with the given name in any project."""
+    status_id_rows = self.statusdef_tbl.Select(
+        cnxn, cols=['id'], status=status)
+    status_ids = [row[0] for row in status_id_rows]
+    return status_ids
+
+  # TODO(jrobbins): regex matching for status values.
+
+  ### Issue tracker configuration objects
+
+  def GetProjectConfigs(self, cnxn, project_ids, use_cache=True):
+    """Get several project issue config objects."""
+    config_dict, missed_ids = self.config_2lc.GetAll(
+        cnxn, project_ids, use_cache=use_cache)
+    assert not missed_ids
+    return config_dict
+
+  def GetProjectConfig(self, cnxn, project_id, use_cache=True):
+    """Load a ProjectIssueConfig for the specified project from the database.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the current project.
+      use_cache: if False, always hit the database.
+
+    Returns:
+      A ProjectIssueConfig describing how the issue tracker in the specified
+      project is configured.  Projects only have a stored ProjectIssueConfig if
+      a project owner has edited the configuration.  Other projects use a
+      default configuration.
+    """
+    config_dict = self.GetProjectConfigs(
+        cnxn, [project_id], use_cache=use_cache)
+    return config_dict[project_id]
+
+  def TemplatesWithComponent(self, cnxn, component_id, config):
+    """Returns all templates with the specified component.
+
+    Args:
+      cnxn: connection to SQL database.
+      component_id: int component id.
+      config: ProjectIssueConfig instance.
+    """
+    template2component_rows = self.template2component_tbl.Select(
+        cnxn, cols=['template_id'], component_id=component_id)
+    template_ids = [r[0] for r in template2component_rows]
+    return [t for t in config.templates if t.template_id in template_ids]
+
+  def StoreConfig(self, cnxn, config):
+    """Update an issue config in the database.
+
+    Args:
+      cnxn: connection to SQL database.
+      config: ProjectIssueConfig PB to update.
+    """
+    # TODO(jrobbins): Convert default template index values into foreign
+    # key references.  Updating an entire config might require (1) adding
+    # new templates, (2) updating the config with new foreign key values,
+    # and finally (3) deleting only the specific templates that should be
+    # deleted.
+    self.projectissueconfig_tbl.InsertRow(
+        cnxn, replace=True,
+        project_id=config.project_id,
+        statuses_offer_merge=' '.join(config.statuses_offer_merge),
+        exclusive_label_prefixes=' '.join(config.exclusive_label_prefixes),
+        default_template_for_developers=config.default_template_for_developers,
+        default_template_for_users=config.default_template_for_users,
+        default_col_spec=config.default_col_spec,
+        default_sort_spec=config.default_sort_spec,
+        default_x_attr=config.default_x_attr,
+        default_y_attr=config.default_y_attr,
+        custom_issue_entry_url=config.custom_issue_entry_url,
+        commit=False)
+
+    self._UpdateTemplates(cnxn, config)
+    self._UpdateWellKnownLabels(cnxn, config)
+    self._UpdateWellKnownStatuses(cnxn, config)
+    cnxn.Commit()
+
+  def _UpdateTemplates(self, cnxn, config):
+    """Update the templates part of a project's issue configuration.
+
+    Args:
+      cnxn: connection to SQL database.
+      config: ProjectIssueConfig PB to update in the DB.
+    """
+    # Delete dependent rows of existing templates.  It is all rewritten below.
+    template_id_rows = self.template_tbl.Select(
+      cnxn, cols=['id'], project_id=config.project_id)
+    template_ids = [row[0] for row in template_id_rows]
+    self.template2label_tbl.Delete(
+      cnxn, template_id=template_ids, commit=False)
+    self.template2component_tbl.Delete(
+      cnxn, template_id=template_ids, commit=False)
+    self.template2admin_tbl.Delete(
+      cnxn, template_id=template_ids, commit=False)
+    self.template2fieldvalue_tbl.Delete(
+      cnxn, template_id=template_ids, commit=False)
+    self.template_tbl.Delete(
+      cnxn, project_id=config.project_id, commit=False)
+
+    # Now, update existing ones and add new ones.
+    template_rows = []
+    for template in config.templates:
+      row = (template.template_id,
+             config.project_id,
+             template.name,
+             template.content,
+             template.summary,
+             template.summary_must_be_edited,
+             template.owner_id or None,
+             template.status,
+             template.members_only,
+             template.owner_defaults_to_member,
+             template.component_required)
+      template_rows.append(row)
+
+    # Maybe first insert ones that have a template_id and then insert new ones
+    # separately.
+    generated_ids = self.template_tbl.InsertRows(
+        cnxn, TEMPLATE_COLS, template_rows, replace=True, commit=False,
+        return_generated_ids=True)
+    logging.info('generated_ids is %r', generated_ids)
+    for template in config.templates:
+      if not template.template_id:
+        # Get IDs from the back of the list because the original template IDs
+        # have already been added to template_rows.
+        template.template_id = generated_ids.pop()
+
+    template2label_rows = []
+    template2component_rows = []
+    template2admin_rows = []
+    template2fieldvalue_rows = []
+    for template in config.templates:
+      for label in template.labels:
+        if label:
+          template2label_rows.append((template.template_id, label))
+      for component_id in template.component_ids:
+        template2component_rows.append((template.template_id, component_id))
+      for admin_id in template.admin_ids:
+        template2admin_rows.append((template.template_id, admin_id))
+      for fv in template.field_values:
+        template2fieldvalue_rows.append(
+            (template.template_id, fv.field_id, fv.int_value, fv.str_value,
+             fv.user_id or None))
+
+    self.template2label_tbl.InsertRows(
+        cnxn, TEMPLATE2LABEL_COLS, template2label_rows, ignore=True,
+        commit=False)
+    self.template2component_tbl.InsertRows(
+        cnxn, TEMPLATE2COMPONENT_COLS, template2component_rows, commit=False)
+    self.template2admin_tbl.InsertRows(
+        cnxn, TEMPLATE2ADMIN_COLS, template2admin_rows, commit=False)
+    self.template2fieldvalue_tbl.InsertRows(
+        cnxn, TEMPLATE2FIELDVALUE_COLS, template2fieldvalue_rows, commit=False)
+
+  def _UpdateWellKnownLabels(self, cnxn, config):
+    """Update the labels part of a project's issue configuration.
+
+    Args:
+      cnxn: connection to SQL database.
+      config: ProjectIssueConfig PB to update in the DB.
+    """
+    update_labeldef_rows = []
+    new_labeldef_rows = []
+    for rank, wkl in enumerate(config.well_known_labels):
+      # We must specify label ID when replacing, otherwise a new ID is made.
+      label_id = self.LookupLabelID(
+          cnxn, config.project_id, wkl.label, autocreate=False)
+      if label_id:
+        row = (label_id, config.project_id, rank, wkl.label,
+               wkl.label_docstring, wkl.deprecated)
+        update_labeldef_rows.append(row)
+      else:
+        row = (
+            config.project_id, rank, wkl.label, wkl.label_docstring,
+            wkl.deprecated)
+        new_labeldef_rows.append(row)
+
+    self.labeldef_tbl.Update(
+        cnxn, {'rank': None}, project_id=config.project_id, commit=False)
+    self.labeldef_tbl.InsertRows(
+        cnxn, LABELDEF_COLS, update_labeldef_rows, replace=True, commit=False)
+    self.labeldef_tbl.InsertRows(
+        cnxn, LABELDEF_COLS[1:], new_labeldef_rows, commit=False)
+    self.label_row_2lc.InvalidateKeys(cnxn, [config.project_id])
+    self.label_cache.Invalidate(cnxn, config.project_id)
+
+  def _UpdateWellKnownStatuses(self, cnxn, config):
+    """Update the status part of a project's issue configuration.
+
+    Args:
+      cnxn: connection to SQL database.
+      config: ProjectIssueConfig PB to update in the DB.
+    """
+    update_statusdef_rows = []
+    new_statusdef_rows = []
+    for rank, wks in enumerate(config.well_known_statuses):
+      # We must specify label ID when replacing, otherwise a new ID is made.
+      status_id = self.LookupStatusID(cnxn, config.project_id, wks.status,
+                                      autocreate=False)
+      if status_id is not None:
+        row = (status_id, config.project_id, rank, wks.status,
+               bool(wks.means_open), wks.status_docstring, wks.deprecated)
+        update_statusdef_rows.append(row)
+      else:
+        row = (config.project_id, rank, wks.status,
+               bool(wks.means_open), wks.status_docstring, wks.deprecated)
+        new_statusdef_rows.append(row)
+
+    self.statusdef_tbl.Update(
+        cnxn, {'rank': None}, project_id=config.project_id, commit=False)
+    self.statusdef_tbl.InsertRows(
+        cnxn, STATUSDEF_COLS, update_statusdef_rows, replace=True,
+        commit=False)
+    self.statusdef_tbl.InsertRows(
+        cnxn, STATUSDEF_COLS[1:], new_statusdef_rows, commit=False)
+    self.status_row_2lc.InvalidateKeys(cnxn, [config.project_id])
+    self.status_cache.Invalidate(cnxn, config.project_id)
+
+  def UpdateConfig(
+      self, cnxn, project, well_known_statuses=None,
+      statuses_offer_merge=None, well_known_labels=None,
+      excl_label_prefixes=None, templates=None,
+      default_template_for_developers=None, default_template_for_users=None,
+      list_prefs=None, restrict_to_known=None):
+    """Update project's issue tracker configuration with the given info.
+
+    Args:
+      cnxn: connection to SQL database.
+      project: the project in which to update the issue tracker config.
+      well_known_statuses: [(status_name, docstring, means_open, deprecated),..]
+      statuses_offer_merge: list of status values that trigger UI to merge.
+      well_known_labels: [(label_name, docstring, deprecated),...]
+      excl_label_prefixes: list of prefix strings.  Each issue should
+          have only one label with each of these prefixed.
+      templates: List of PBs for issue templates.
+      default_template_for_developers: int ID of template to use for devs.
+      default_template_for_users: int ID of template to use for non-members.
+      list_prefs: defaults for columns and sorting.
+      restrict_to_known: optional bool to allow project owners
+          to limit issue status and label values to only the well-known ones.
+
+    Returns:
+      The updated ProjectIssueConfig PB.
+    """
+    project_id = project.project_id
+    project_config = self.GetProjectConfig(cnxn, project_id, use_cache=False)
+
+    if well_known_statuses is not None:
+      tracker_bizobj.SetConfigStatuses(project_config, well_known_statuses)
+
+    if statuses_offer_merge is not None:
+      project_config.statuses_offer_merge = statuses_offer_merge
+
+    if well_known_labels is not None:
+      tracker_bizobj.SetConfigLabels(project_config, well_known_labels)
+
+    if excl_label_prefixes is not None:
+      project_config.exclusive_label_prefixes = excl_label_prefixes
+
+    if templates is not None:
+      project_config.templates = templates
+
+    if default_template_for_developers is not None:
+      project_config.default_template_for_developers = (
+          default_template_for_developers)
+    if default_template_for_users is not None:
+      project_config.default_template_for_users = default_template_for_users
+
+    if list_prefs:
+      default_col_spec, default_sort_spec, x_attr, y_attr = list_prefs
+      project_config.default_col_spec = default_col_spec
+      project_config.default_sort_spec = default_sort_spec
+      project_config.default_x_attr = x_attr
+      project_config.default_y_attr = y_attr
+
+    if restrict_to_known is not None:
+      project_config.restrict_to_known = restrict_to_known
+
+    self.StoreConfig(cnxn, project_config)
+    self.config_2lc.InvalidateKeys(cnxn, [project_id])
+    self.InvalidateMemcacheForEntireProject(project_id)
+    # Invalidate all issue caches in all frontends to clear out
+    # sorting.art_values_cache which now has wrong sort orders.
+    cache_manager = self.config_2lc.cache.cache_manager
+    cache_manager.StoreInvalidateAll(cnxn, 'issue')
+
+    return project_config
+
+  def ExpungeConfig(self, cnxn, project_id):
+    """Completely delete the specified project config from the database."""
+    logging.info('expunging the config for %r', project_id)
+    template_id_rows = self.template_tbl.Select(
+        cnxn, cols=['id'], project_id=project_id)
+    template_ids = [row[0] for row in template_id_rows]
+    self.template2label_tbl.Delete(cnxn, template_id=template_ids)
+    self.template2component_tbl.Delete(cnxn, template_id=template_ids)
+    self.template_tbl.Delete(cnxn, project_id=project_id)
+    self.statusdef_tbl.Delete(cnxn, project_id=project_id)
+    self.labeldef_tbl.Delete(cnxn, project_id=project_id)
+    self.projectissueconfig_tbl.Delete(cnxn, project_id=project_id)
+
+    self.config_2lc.InvalidateKeys(cnxn, [project_id])
+
+  ### Custom field definitions
+
+  def CreateFieldDef(
+      self, cnxn, project_id, field_name, field_type_str, applic_type,
+      applic_pred, is_required, is_multivalued,
+      min_value, max_value, regex, needs_member, needs_perm,
+      grants_perm, notify_on, docstring, admin_ids):
+    """Create a new field definition with the given info.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the current project.
+      field_name: name of the new custom field.
+      field_type_str: string identifying the type of the custom field.
+      applic_type: string specifying issue type the field is applicable to.
+      applic_pred: string condition to test if the field is applicable.
+      is_required: True if the field should be required on issues.
+      is_multivalued: True if the field can occur multiple times on one issue.
+      min_value: optional validation for int_type fields.
+      max_value: optional validation for int_type fields.
+      regex: optional validation for str_type fields.
+      needs_member: optional validation for user_type fields.
+      needs_perm: optional validation for user_type fields.
+      grants_perm: optional string for perm to grant any user named in field.
+      notify_on: int enum of when to notify users named in field.
+      docstring: string describing this field.
+      admin_ids: list of additional user IDs who can edit this field def.
+
+    Returns:
+      Integer field_id of the new field definition.
+    """
+    field_id = self.fielddef_tbl.InsertRow(
+        cnxn, project_id=project_id,
+        field_name=field_name, field_type=field_type_str,
+        applicable_type=applic_type, applicable_predicate=applic_pred,
+        is_required=is_required, is_multivalued=is_multivalued,
+        min_value=min_value, max_value=max_value, regex=regex,
+        needs_member=needs_member, needs_perm=needs_perm,
+        grants_perm=grants_perm, notify_on=NOTIFY_ON_ENUM[notify_on],
+        docstring=docstring, commit=False)
+    self.fielddef2admin_tbl.InsertRows(
+        cnxn, FIELDDEF2ADMIN_COLS,
+        [(field_id, admin_id) for admin_id in admin_ids],
+        commit=False)
+    cnxn.Commit()
+    self.config_2lc.InvalidateKeys(cnxn, [project_id])
+    self.InvalidateMemcacheForEntireProject(project_id)
+    return field_id
+
+  def _DeserializeFields(self, def_rows):
+    """Convert field defs into bi-directional mappings of names and IDs."""
+    field_id_to_name = {
+        field_id: field
+        for field_id, _pid, _rank, field, _doc in def_rows}
+    field_name_to_id = {
+        field.lower(): field_id
+        for field_id, field in field_id_to_name.iteritems()}
+
+    return field_id_to_name, field_name_to_id
+
+  def GetFieldDefRows(self, cnxn, project_id):
+    """Get SQL result rows for all fields used in the specified project."""
+    pids_to_field_rows, misses = self.field_row_2lc.GetAll(cnxn, [project_id])
+    assert not misses
+    return pids_to_field_rows[project_id]
+
+  def _EnsureFieldCacheEntry(self, cnxn, project_id):
+    """Make sure that self.field_cache has an entry for project_id."""
+    if not self.field_cache.HasItem(project_id):
+      def_rows = self.GetFieldDefRows(cnxn, project_id)
+      self.field_cache.CacheItem(
+          project_id, self._DeserializeFields(def_rows))
+
+  def LookupField(self, cnxn, project_id, field_id):
+    """Lookup a field string given the field_id.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the project where the label is defined or used.
+      field_id: int field ID.
+
+    Returns:
+      Field name string for the given field_id, or None.
+    """
+    self._EnsureFieldCacheEntry(cnxn, project_id)
+    field_id_to_name, _field_name_to_id = self.field_cache.GetItem(
+        project_id)
+    return field_id_to_name.get(field_id)
+
+  def LookupFieldID(self, cnxn, project_id, field):
+    """Look up a field ID.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the project where the fields are defined.
+      field: field string.
+
+    Returns:
+      The field ID for the given field string.
+    """
+    self._EnsureFieldCacheEntry(cnxn, project_id)
+    _field_id_to_name, field_name_to_id = self.field_cache.GetItem(
+        project_id)
+    return field_name_to_id.get(field.lower())
+
+  def SoftDeleteFieldDef(self, cnxn, project_id, field_id):
+    """Mark the specified field as deleted, it will be reaped later."""
+    self.fielddef_tbl.Update(cnxn, {'is_deleted': True}, id=field_id)
+    self.config_2lc.InvalidateKeys(cnxn, [project_id])
+    self.InvalidateMemcacheForEntireProject(project_id)
+
+  # TODO(jrobbins): GC deleted field defs after field values are gone.
+
+  def UpdateFieldDef(
+      self, cnxn, project_id, field_id, field_name=None,
+      applicable_type=None, applicable_predicate=None, is_required=None,
+      is_multivalued=None, min_value=None, max_value=None, regex=None,
+      needs_member=None, needs_perm=None, grants_perm=None, notify_on=None,
+      docstring=None, admin_ids=None):
+    """Update the specified field definition."""
+    new_values = {}
+    if field_name is not None:
+      new_values['field_name'] = field_name
+    if applicable_type is not None:
+      new_values['applicable_type'] = applicable_type
+    if applicable_predicate is not None:
+      new_values['applicable_predicate'] = applicable_predicate
+    if is_required is not None:
+      new_values['is_required'] = bool(is_required)
+    if is_multivalued is not None:
+      new_values['is_multivalued'] = bool(is_multivalued)
+    if min_value is not None:
+      new_values['min_value'] = min_value
+    if max_value is not None:
+      new_values['max_value'] = max_value
+    if regex is not None:
+      new_values['regex'] = regex
+    if needs_member is not None:
+      new_values['needs_member'] = needs_member
+    if needs_perm is not None:
+      new_values['needs_perm'] = needs_perm
+    if grants_perm is not None:
+      new_values['grants_perm'] = grants_perm
+    if notify_on is not None:
+      new_values['notify_on'] = NOTIFY_ON_ENUM[notify_on]
+    if docstring is not None:
+      new_values['docstring'] = docstring
+
+    self.fielddef_tbl.Update(cnxn, new_values, id=field_id, commit=False)
+    self.fielddef2admin_tbl.Delete(cnxn, field_id=field_id, commit=False)
+    self.fielddef2admin_tbl.InsertRows(
+        cnxn, FIELDDEF2ADMIN_COLS,
+        [(field_id, admin_id) for admin_id in admin_ids],
+        commit=False)
+    cnxn.Commit()
+    self.config_2lc.InvalidateKeys(cnxn, [project_id])
+    self.InvalidateMemcacheForEntireProject(project_id)
+
+  ### Component definitions
+
+  def FindMatchingComponentIDsAnyProject(self, cnxn, path_list, exact=True):
+    """Look up component IDs across projects.
+
+    Args:
+      cnxn: connection to SQL database.
+      path_list: list of component path prefixes.
+      exact: set to False to include all components which have one of the
+          given paths as their ancestor, instead of exact matches.
+
+    Returns:
+      A list of component IDs of component's whose paths match path_list.
+    """
+    or_terms = []
+    args = []
+    for path in path_list:
+      or_terms.append('path = %s')
+      args.append(path)
+
+    if not exact:
+      for path in path_list:
+        or_terms.append('path LIKE %s')
+        args.append(path + '>%')
+
+    cond_str = '(' + ' OR '.join(or_terms) + ')'
+    rows = self.componentdef_tbl.Select(
+        cnxn, cols=['id'], where=[(cond_str, args)])
+    return [row[0] for row in rows]
+
+  def CreateComponentDef(
+      self, cnxn, project_id, path, docstring, deprecated, admin_ids, cc_ids,
+      created, creator_id):
+    """Create a new component definition with the given info.
+
+    Args:
+      cnxn: connection to SQL database.
+      project_id: int ID of the current project.
+      path: string pathname of the new component.
+      docstring: string describing this field.
+      deprecated: whether or not this should be autocompleted
+      admin_ids: list of int IDs of users who can administer.
+      cc_ids: list of int IDs of users to notify when an issue in
+          this component is updated.
+      created: timestamp this component was created at.
+      creator_id: int ID of user who created this component.
+
+    Returns:
+      Integer component_id of the new component definition.
+    """
+    component_id = self.componentdef_tbl.InsertRow(
+        cnxn, project_id=project_id, path=path, docstring=docstring,
+        deprecated=deprecated, created=created, creator_id=creator_id,
+        commit=False)
+    self.component2admin_tbl.InsertRows(
+        cnxn, COMPONENT2ADMIN_COLS,
+        [(component_id, admin_id) for admin_id in admin_ids],
+        commit=False)
+    self.component2cc_tbl.InsertRows(
+        cnxn, COMPONENT2CC_COLS,
+        [(component_id, cc_id) for cc_id in cc_ids],
+        commit=False)
+    cnxn.Commit()
+    self.config_2lc.InvalidateKeys(cnxn, [project_id])
+    self.InvalidateMemcacheForEntireProject(project_id)
+    return component_id
+
+  def UpdateComponentDef(
+      self, cnxn, project_id, component_id, path=None, docstring=None,
+      deprecated=None, admin_ids=None, cc_ids=None, created=None,
+      creator_id=None, modified=None, modifier_id=None):
+    """Update the specified component definition."""
+    new_values = {}
+    if path is not None:
+      assert path
+      new_values['path'] = path
+    if docstring is not None:
+      new_values['docstring'] = docstring
+    if deprecated is not None:
+      new_values['deprecated'] = deprecated
+    if created is not None:
+      new_values['created'] = created
+    if creator_id is not None:
+      new_values['creator_id'] = creator_id
+    if modified is not None:
+      new_values['modified'] = modified
+    if modifier_id is not None:
+      new_values['modifier_id'] = modifier_id
+
+    if admin_ids is not None:
+      self.component2admin_tbl.Delete(
+          cnxn, component_id=component_id, commit=False)
+      self.component2admin_tbl.InsertRows(
+          cnxn, COMPONENT2ADMIN_COLS,
+          [(component_id, admin_id) for admin_id in admin_ids],
+          commit=False)
+
+    if cc_ids is not None:
+      self.component2cc_tbl.Delete(
+          cnxn, component_id=component_id, commit=False)
+      self.component2cc_tbl.InsertRows(
+          cnxn, COMPONENT2CC_COLS,
+          [(component_id, cc_id) for cc_id in cc_ids],
+          commit=False)
+
+    self.componentdef_tbl.Update(
+        cnxn, new_values, id=component_id, commit=False)
+    cnxn.Commit()
+    self.config_2lc.InvalidateKeys(cnxn, [project_id])
+    self.InvalidateMemcacheForEntireProject(project_id)
+
+  def DeleteComponentDef(self, cnxn, project_id, component_id):
+    """Delete the specified component definition."""
+    self.component2cc_tbl.Delete(
+        cnxn, component_id=component_id, commit=False)
+    self.component2admin_tbl.Delete(
+        cnxn, component_id=component_id, commit=False)
+    self.componentdef_tbl.Delete(cnxn, id=component_id, commit=False)
+    cnxn.Commit()
+    self.config_2lc.InvalidateKeys(cnxn, [project_id])
+    self.InvalidateMemcacheForEntireProject(project_id)
+
+  ### Memcache management
+
+  def InvalidateMemcache(self, issues, key_prefix=''):
+    """Delete the memcache entries for issues and their project-shard pairs."""
+    memcache.delete_multi(
+        [str(issue.issue_id) for issue in issues], key_prefix='issue:')
+    project_shards = set(
+        (issue.project_id, issue.issue_id % settings.num_logical_shards)
+        for issue in issues)
+    self._InvalidateMemcacheShards(project_shards, key_prefix=key_prefix)
+
+  def _InvalidateMemcacheShards(self, project_shards, key_prefix=''):
+    """Delete the memcache entries for the given project-shard pairs.
+
+    Deleting these rows does not delete the actual cached search results
+    but it does mean that they will be considered stale and thus not used.
+
+    Args:
+      project_shards: list of (pid, sid) pairs.
+      key_prefix: string to pass as memcache key prefix.
+    """
+    cache_entries = ['%d;%d' % ps for ps in project_shards]
+    # Whenever any project is invalidated, also invalidate the 'all'
+    # entry that is used in site-wide searches.
+    shard_id_set = {sid for _pid, sid in project_shards}
+    cache_entries.extend(('all;%d' % sid) for sid in shard_id_set)
+
+    memcache.delete_multi(cache_entries, key_prefix=key_prefix)
+
+  def InvalidateMemcacheForEntireProject(self, project_id):
+    """Delete the memcache entries for all searches in a project."""
+    project_shards = set((project_id, shard_id)
+                         for shard_id in range(settings.num_logical_shards))
+    self._InvalidateMemcacheShards(project_shards)
+    memcache.delete_multi([str(project_id)], key_prefix='config:')
+    memcache.delete_multi([str(project_id)], key_prefix='label_rows:')
+    memcache.delete_multi([str(project_id)], key_prefix='status_rows:')
+    memcache.delete_multi([str(project_id)], key_prefix='field_rows:')
+
+
+class Error(Exception):
+  """Base class for errors from this module."""
+  pass
+
+
+class NoSuchComponentException(Error):
+  """No component with the specified name exists."""
+  pass
+
+
+class InvalidComponentNameException(Error):
+  """The component name is invalid."""
+  pass