Update LogDog client library to generate URLs.

client/libs/logdog/streamname.py

 # Copyright 2016 The LUCI Authors. All rights reserved.
 # Use of this source code is governed under the Apache License, Version 2.0
 # that can be found in the LICENSE file.
 
+import collections
 import re
 import string
 import types
+import urllib
+import urlparse
 
 _ALNUM_CHARS = string.ascii_letters + string.digits
 _SEGMENT_RE_BASE = r'[a-zA-Z0-9][a-zA-Z0-9:_\-.]*'
 _STREAM_NAME_RE = re.compile('^(' + _SEGMENT_RE_BASE + ')(/' +
                              _SEGMENT_RE_BASE + ')*$')
 _MAX_STREAM_NAME_LENGTH = 4096
 
 _MAX_TAG_KEY_LENGTH = 64
 _MAX_TAG_VALUE_LENGTH = 4096
 
@@ skipping 80 matching lines @@
   """
   # Alphanumeric check.
   if ch in _ALNUM_CHARS:
     return True
   if first:
     # The first character must be alphanumeric.
     return False
 
   # Check additional middle-name characters:
   return ch in ':_-./'
+
+
+class StreamPath(collections.namedtuple('_StreamPath', ('prefix', 'name'))):
+  """StreamPath is a full stream path.
+
+  This consists of both a stream prefix and a stream name.
+
+  When constructed with parse or make, the stream path must be completely valid.
+  However, invalid stream paths may be constructed by manually instantiation.
+  This can be useful for wildcard query values (e.g., "prefix='foo/*/bar/**'").
+  """
+
+  @classmethod
+  def make(cls, prefix, name):
+    """Returns (StreamPath): The validated StreamPath instance.
+
+    Args:
+      prefix (str): the prefix component
+      name (str): the name component
+
+    Raises:
+      ValueError: If path is not a full, valid stream path string.
+    """
+    inst = cls(prefix=prefix, name=name)
+    inst.validate()
+    return inst
+
+  @classmethod
+  def parse(cls, path):
+    """Returns (StreamPath): The parsed StreamPath instance.
+
+    Args:
+      path (str): the full stream path to parse.
+
+    Raises:
+      ValueError: If path is not a full, valid stream path string.
+    """
+    parts = path.split('/+/', 1)
+    if len(parts) != 2:
+      raise ValueError('Not a full stream path: [%s]' % (path,))
+    return cls.make(*parts)
+
+  def validate(self):
+    """Raises: ValueError if this is not a valid stream name."""
+    try:
+      validate_stream_name(self.prefix)
+    except ValueError as e:
+      raise ValueError('Invalid prefix component [%s]: %s' % (
+          self.prefix, e.message,))
+
+    try:
+      validate_stream_name(self.name)
+    except ValueError as e:
+      raise ValueError('Invalid name component [%s]: %s' % (
+          self.name, e.message,))
+
+  def __str__(self):
+    return '%s/+/%s' % (self.prefix, self.name)
+
+
+def get_logdog_viewer_url(host, project, *stream_paths):
+  """Returns (str): The LogDog viewer URL for the named stream(s).
+
+  Args:
+    host (str): The name of the Coordiantor host.
+    project (str): The project name.
+    stream_paths: A set of StreamPath instances for the stream paths to
+        generate the URL for.
+  """
+  return urlparse.urlunparse((
+    'https', # Scheme
+    host, # netloc
+    'v/', # path
+    '', # params
+    '&'.join(('s=%s' % (urllib.quote('%s/%s' % (project, path), safe=''))
+              for path in stream_paths)), # query
+    '', # fragment
+  ))