Update cbuildbot.py and prebuilt.py to deduplicate preflight prebuilts.

chromite/lib/binpkg.py

Index: chromite/lib/binpkg.py
diff --git a/chromite/lib/binpkg.py b/chromite/lib/binpkg.py
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--- /dev/null
+++ b/chromite/lib/binpkg.py
@@ -0,0 +1,307 @@
+# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+#
+# Adapted from portage/getbinpkg.py -- Portage binary-package helper functions
+# Copyright 2003-2004 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+import operator
+import os
+import tempfile
+import time
+import urllib2
+import urlparse
+
+class PackageIndex(object):
+  """A parser for the Portage Packages index file.
+
+  The Portage Packages index file serves to keep track of what packages are
+  included in a tree. It contains the following sections:
+    1) The header. The header tracks general key/value pairs that don't apply
+       to any specific package. E.g., it tracks the base URL of the packages
+       file, and the number of packages included in the file. The header is
+       terminated by a blank line.
+    2) The body. The body is a list of packages. Each package contains a list
+       of key/value pairs. Packages are either terminated by a blank line or
+       by the end of the file. Every package has a CPV entry, which serves as
+       a unique identifier for the package.
+   """
+
+  def __init__(self):
+    """Constructor."""
+
+    # The header tracks general key/value pairs that don't apply to any
+    # specific package. E.g., it tracks the base URL of the packages.
+    self.header = {}
+
+    # A list of packages (stored as a list of dictionaries).
+    self.packages = []
+
+    # Whether or not the PackageIndex has been modified since the last time it
+    # was written.
+    self.modified = False
+
+  def _PopulateDuplicateDB(self, db):
+    """Populate db with SHA1 -> URL mapping for packages.
+
+    Args:
+      db: Dictionary to populate with SHA1 -> URL mapping for packages.
+    """
+
+    uri = self.header['URI']
+    for pkg in self.packages:
+      cpv, sha1 = pkg['CPV'], pkg['SHA1']
+      path = pkg.get('PATH', cpv + '.tbz2')
+      db[sha1] = urlparse.urljoin(uri, path)
+
+  def _ReadPkgIndex(self, pkgfile):
+    """Read a list of key/value pairs from the Packages file into a dictionary.
+
+    Both header entries and package entries are lists of key/value pairs, so
+    they can both be read by this function. Entries can be terminated by empty
+    lines or by the end of the file.
+
+    This function will read lines from the specified file until it encounters
+    the a blank line or the end of the file.
+
+    Keys and values in the Packages file are separated by a colon and a space.
+    Keys may contain capital letters, numbers, and underscores, but may not
+    contain colons. Values may contain any character except a newline. In
+    particular, it is normal for values to contain colons.
+
+    Lines that have content, and do not contain a valid key/value pair, are
+    ignored. This is for compatibility with the Portage package parser, and
+    to allow for future extensions to the Packages file format.
+
+    All entries must contain at least one key/value pair. If the end of the
+    fils is reached, an empty dictionary is returned.
+
+    Args:
+      pkgfile: A python file object.
+
+    Returns the dictionary of key-value pairs that was read from the file.
+    """
+    d = {}
+    for line in pkgfile:
+      line = line.rstrip('\n')
+      if not line:
+        assert d, 'Packages entry must contain at least one key/value pair'
+        break
+      line = line.split(': ', 1)
+      if len(line) == 2:
+        k, v = line
+        d[k] = v
+    return d
+
+  def _WritePkgIndex(self, pkgfile, entry):
+    """Write header entry or package entry to packages file.
+
+    The keys and values will be separated by a colon and a space. The entry
+    will be terminated by a blank line.
+
+    Args:
+      pkgfile: A python file object.
+      entry: A dictionary of the key/value pairs to write.
+    """
+    lines = ['%s: %s' % (k, v) for k, v in sorted(entry.items()) if v]
+    pkgfile.write('%s\n\n' % '\n'.join(lines))
+
+  def _ReadHeader(self, pkgfile):
+    """Read header of packages file.
+
+    Args:
+      pkgfile: A python file object.
+    """
+    assert not self.header, 'Should only read header once.'
+    self.header = self._ReadPkgIndex(pkgfile)
+
+  def _ReadBody(self, pkgfile):
+    """Read body of packages file.
+
+    Before calling this function, you must first read the header (using
+    _ReadHeader).
+
+    Args:
+      pkgfile: A python file object.
+    """
+    assert self.header, 'Should read header first.'
+    assert not self.packages, 'Should only read body once.'
+
+    # Read all of the sections in the body by looping until we reach the end
+    # of the file.
+    while True:
+      d = self._ReadPkgIndex(pkgfile)
+      if not d:
+        break
+      if 'CPV' in d:
+        self.packages.append(d)
+
+  def Read(self, pkgfile):
+    """Read the entire packages file.
+
+    Args:
+      pkgfile: A python file object.
+    """
+    self._ReadHeader(pkgfile)
+    self._ReadBody(pkgfile)
+
+  def RemoveFilteredPackages(self, filter_fn):
+    """Remove packages which match filter_fn.
+
+    Args:
+      filter_fn: A function which operates on packages. If it returns True,
+                 the package should be removed.
+    """
+
+    filtered = [p for p in self.packages if not filter_fn(p)]
+    if filtered != self.packages:
+      self.modified = True
+      self.packages = filtered
+
+  def ResolveDuplicateUploads(self, pkgindexes):
+    """Point packages at files that have already been uploaded.
+
+    For each package in our index, check if there is an existing package that
+    has already been uploaded to the same base URI. If so, point that package
+    at the existing file, so that we don't have to upload the file.
+
+    Args:
+      pkgindexes: A list of PackageIndex objects containing info about packages
+        that have already been uploaded.
+
+    Returns:
+      A list of the packages that still need to be uploaded.
+    """
+    db = {}
+    for pkgindex in pkgindexes:
+      pkgindex._PopulateDuplicateDB(db)
+
+    uploads = []
+    base_uri = self.header['URI']
+    for pkg in self.packages:
+      sha1 = pkg['SHA1']
+      uri = db.get(sha1)
+      if uri and uri.startswith(base_uri):
+        pkg['PATH'] = uri[len(base_uri):].lstrip('/')
+      else:
+        uploads.append(pkg)
+    return uploads
+
+  def SetUploadLocation(self, base_uri, path_prefix):
+    """Set upload location to base_uri + path_prefix.
+
+    Args:
+      base_uri: Base URI for all packages in the file. We set
+        self.header['URI'] to this value, so all packages must live under
+        this directory.
+      path_prefix: Path prefix to use for all current packages in the file.
+        This will be added to the beginning of the path for every package.
+    """
+    self.header['URI'] = base_uri
+    for pkg in self.packages:
+      pkg['PATH'] = urlparse.urljoin(path_prefix, pkg['CPV'] + '.tbz2')
+
+  def Write(self, pkgfile):
+    """Write a packages file to disk.
+
+    If 'modified' flag is set, the TIMESTAMP and PACKAGES fields in the header
+    will be updated before writing to disk.
+
+    Args:
+      pkgfile: A python file object.
+    """
+    if self.modified:
+      self.header['TIMESTAMP'] = str(long(time.time()))
+      self.header['PACKAGES'] = str(len(self.packages))
+      self.modified = False
+    self._WritePkgIndex(pkgfile, self.header)
+    for metadata in sorted(self.packages, key=operator.itemgetter('CPV')):
+      self._WritePkgIndex(pkgfile, metadata)
+
+  def WriteToNamedTemporaryFile(self):
+    """Write pkgindex to a temporary file.
+
+    Args:
+     pkgindex: The PackageIndex object.
+
+    Returns:
+      A temporary file containing the packages from pkgindex.
+    """
+    f = tempfile.NamedTemporaryFile()
+    self.Write(f)
+    f.flush()
+    f.seek(0)
+    return f
+
+
+def _RetryUrlOpen(url, tries=3):
+  """Open the specified url, retrying if we run into temporary errors.
+
+  We retry for both network errors and 5xx Server Errors. We do not retry
+  for HTTP errors with a non-5xx code.
+
+  Args:
+    url: The specified url.
+    tries: The number of times to try.
+
+  Returns:
+    The result of urllib2.urlopen(url).
+  """
+  for i in range(tries):
+    try:
+      return urllib2.urlopen(url)
+    except urllib2.HTTPError as e:
+      if i + 1 >= tries or e.code < 500:
+        raise
+      else:
+        print 'Cannot GET %s: %s' % (url, str(e))
+    except urllib2.URLError as e:
+      if i + 1 >= tries:
+        raise
+      else:
+        print 'Cannot GET %s: %s' % (url, str(e))
+    print 'Sleeping for 10 seconds before retrying...'
+    time.sleep(10)
+
+
+def GrabRemotePackageIndex(binhost_url):
+  """Grab the latest binary package database from the specified URL.
+
+  Args:
+    binhost_url: Base URL of remote packages (PORTAGE_BINHOST).
+
+  Returns:
+    A PackageIndex object, if the Packages file can be retrieved. If the
+    server returns status code 404, None is returned.
+  """
+
+  url = urlparse.urljoin(binhost_url, 'Packages')
+  try:
+    f = _RetryUrlOpen(url)
+  except urllib2.HTTPError as e:
+    if e.code == 404:
+      return None
+    raise
+
+  pkgindex = PackageIndex()
+  pkgindex.Read(f)
+  pkgindex.header.setdefault('URI', binhost_url)
+  f.close()
+  return pkgindex
+
+
+def GrabLocalPackageIndex(package_path):
+  """Read a local packages file from disk into a PackageIndex() object.
+
+  Args:
+    package_path: Directory containing Packages file.
+
+  Returns:
+    A PackageIndex object.
+  """
+  packages_file = file(os.path.join(package_path, 'Packages'))
+  pkgindex = PackageIndex()
+  pkgindex.Read(packages_file)
+  packages_file.close()
+  return pkgindex