diff --git a/services/tracker_fulltext.py b/services/tracker_fulltext.py
new file mode 100644
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--- /dev/null
+++ b/services/tracker_fulltext.py
@@ -0,0 +1,320 @@
+# Copyright 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file or at
+# https://developers.google.com/open-source/licenses/bsd
+
+"""A set of functions that provide fulltext search for issues."""
+from __future__ import print_function
+from __future__ import division
+from __future__ import absolute_import
+
+import collections
+import logging
+import time
+
+from six import string_types
+
+from google.appengine.api import search
+
+import settings
+from framework import framework_constants
+from framework import framework_helpers
+from framework import framework_views
+from services import fulltext_helpers
+from tracker import tracker_bizobj
+
+
+# When updating and re-indexing all issues in a project, work in batches
+# of this size to manage memory usage and avoid rpc timeouts.
+_INDEX_BATCH_SIZE = 40
+
+
+# The user can search for text that occurs specifically in these
+# parts of an issue.
+ISSUE_FULLTEXT_FIELDS = ['summary', 'description', 'comment']
+# Note: issue documents also contain a "metadata" field, but we do not
+# expose that to users.  Issue metadata can be searched in a structured way
+# by giving a specific field name such as "owner:" or "status:". The metadata
+# search field exists only for fulltext queries that do not specify any field.
+
+
+def IndexIssues(cnxn, issues, user_service, issue_service, config_service):
+  """(Re)index all the given issues.
+
+  Args:
+    cnxn: connection to SQL database.
+    issues: list of Issue PBs to index.
+    user_service: interface to user data storage.
+    issue_service: interface to issue data storage.
+    config_service: interface to configuration data storage.
+  """
+  issues = list(issues)
+  config_dict = config_service.GetProjectConfigs(
+      cnxn, {issue.project_id for issue in issues})
+  for start in range(0, len(issues), _INDEX_BATCH_SIZE):
+    logging.info('indexing issues: %d remaining', len(issues) - start)
+    _IndexIssueBatch(
+        cnxn, issues[start:start + _INDEX_BATCH_SIZE], user_service,
+        issue_service, config_dict)
+
+
+def _IndexIssueBatch(cnxn, issues, user_service, issue_service, config_dict):
+  """Internal method to (re)index the given batch of issues.
+
+  Args:
+    cnxn: connection to SQL database.
+    issues: list of Issue PBs to index.
+    user_service: interface to user data storage.
+    issue_service: interface to issue data storage.
+    config_dict: dict {project_id: config} for all the projects that
+        the given issues are in.
+  """
+  user_ids = tracker_bizobj.UsersInvolvedInIssues(issues)
+  comments_dict = issue_service.GetCommentsForIssues(
+      cnxn, [issue.issue_id for issue in issues])
+  for comments in comments_dict.values():
+    user_ids.update([ic.user_id for ic in comments])
+
+  users_by_id = framework_views.MakeAllUserViews(
+      cnxn, user_service, user_ids)
+  _CreateIssueSearchDocuments(issues, comments_dict, users_by_id, config_dict)
+
+
+def _CreateIssueSearchDocuments(
+    issues, comments_dict, users_by_id, config_dict):
+  """Make the GAE search index documents for the given issue batch.
+
+  Args:
+    issues: list of issues to index.
+    comments_dict: prefetched dictionary of comments on those issues.
+    users_by_id: dictionary {user_id: UserView} so that the email
+        addresses of users who left comments can be found via search.
+    config_dict: dict {project_id: config} for all the projects that
+        the given issues are in.
+  """
+  documents_by_shard = collections.defaultdict(list)
+  for issue in issues:
+    summary = issue.summary
+    # TODO(jrobbins): allow search specifically on explicit vs derived
+    # fields.
+    owner_id = tracker_bizobj.GetOwnerId(issue)
+    owner_email = users_by_id[owner_id].email
+    config = config_dict[issue.project_id]
+    component_paths = []
+    for component_id in issue.component_ids:
+      cd = tracker_bizobj.FindComponentDefByID(component_id, config)
+      if cd:
+        component_paths.append(cd.path)
+
+    field_values = [tracker_bizobj.GetFieldValue(fv, users_by_id)
+                    for fv in issue.field_values]
+    # Convert to string only the values that are not strings already.
+    # This is done because the default encoding in appengine seems to be 'ascii'
+    # and string values might contain unicode characters, so str will fail to
+    # encode them.
+    field_values = [value if isinstance(value, string_types) else str(value)
+                    for value in field_values]
+
+    metadata = '%s %s %s %s %s %s' % (
+        tracker_bizobj.GetStatus(issue),
+        owner_email,
+        [users_by_id[cc_id].email for cc_id in
+         tracker_bizobj.GetCcIds(issue)],
+        ' '.join(component_paths),
+        ' '.join(field_values),
+        ' '.join(tracker_bizobj.GetLabels(issue)))
+    custom_fields = _BuildCustomFTSFields(issue)
+
+    comments = comments_dict.get(issue.issue_id, [])
+    room_for_comments = (framework_constants.MAX_FTS_FIELD_SIZE -
+                         len(summary) -
+                         len(metadata) -
+                         sum(len(cf.value) for cf in custom_fields))
+    comments = _IndexableComments(
+        comments, users_by_id, remaining_chars=room_for_comments)
+    logging.info('len(comments) is %r', len(comments))
+    if comments:
+      description = _ExtractCommentText(comments[0], users_by_id)
+      description = description[:framework_constants.MAX_FTS_FIELD_SIZE]
+      all_comments = ' '. join(
+          _ExtractCommentText(c, users_by_id) for c in comments[1:])
+      all_comments = all_comments[:framework_constants.MAX_FTS_FIELD_SIZE]
+    else:
+      description = ''
+      all_comments = ''
+      logging.info(
+          'Issue %s:%r has zero indexable comments',
+          issue.project_name, issue.local_id)
+
+    logging.info('Building document for %s:%d',
+                 issue.project_name, issue.local_id)
+    logging.info('len(summary) = %d', len(summary))
+    logging.info('len(metadata) = %d', len(metadata))
+    logging.info('len(description) = %d', len(description))
+    logging.info('len(comment) = %d', len(all_comments))
+    for cf in custom_fields:
+      logging.info('len(%s) = %d', cf.name, len(cf.value))
+
+    doc = search.Document(
+        doc_id=str(issue.issue_id),
+        fields=[
+            search.NumberField(name='project_id', value=issue.project_id),
+            search.TextField(name='summary', value=summary),
+            search.TextField(name='metadata', value=metadata),
+            search.TextField(name='description', value=description),
+            search.TextField(name='comment', value=all_comments),
+            ] + custom_fields)
+
+    shard_id = issue.issue_id % settings.num_logical_shards
+    documents_by_shard[shard_id].append(doc)
+
+  start_time = time.time()
+  promises = []
+  for shard_id, documents in documents_by_shard.items():
+    if documents:
+      promises.append(framework_helpers.Promise(
+          _IndexDocsInShard, shard_id, documents))
+
+  for promise in promises:
+    promise.WaitAndGetValue()
+
+  logging.info('Finished %d indexing in shards in %d ms',
+               len(documents_by_shard), int((time.time() - start_time) * 1000))
+
+
+def _IndexableComments(comments, users_by_id, remaining_chars=None):
+  """We only index the comments that are not deleted or banned.
+
+  Args:
+    comments: list of Comment PBs for one issue.
+    users_by_id: Dict of (user_id -> UserView) for all users.
+    remaining_chars: number of characters available for comment text
+       without hitting the GAE search index max document size.
+
+  Returns:
+    A list of comments filtered to not have any deleted comments or
+    comments from banned users.  If the issue has a huge number of
+    comments, only a certain number of the first and last comments
+    are actually indexed.
+  """
+  if remaining_chars is None:
+    remaining_chars = framework_constants.MAX_FTS_FIELD_SIZE
+  allowed_comments = []
+  for comment in comments:
+    user_view = users_by_id.get(comment.user_id)
+    if not (comment.deleted_by or (user_view and user_view.banned)):
+      if comment.is_description and allowed_comments:
+        # index the latest description, but not older descriptions
+        allowed_comments[0] = comment
+      else:
+        allowed_comments.append(comment)
+
+  reasonable_size = (framework_constants.INITIAL_COMMENTS_TO_INDEX +
+                     framework_constants.FINAL_COMMENTS_TO_INDEX)
+  if len(allowed_comments) <= reasonable_size:
+    candidates = allowed_comments
+  else:
+    candidates = (  # Prioritize the description and recent comments.
+      allowed_comments[0:1] +
+      allowed_comments[-framework_constants.FINAL_COMMENTS_TO_INDEX:] +
+      allowed_comments[1:framework_constants.INITIAL_COMMENTS_TO_INDEX])
+
+  total_length = 0
+  result = []
+  for comment in candidates:
+    total_length += len(comment.content)
+    if total_length > remaining_chars:
+      break
+    result.append(comment)
+
+  return result
+
+
+def _IndexDocsInShard(shard_id, documents):
+  search_index = search.Index(
+      name=settings.search_index_name_format % shard_id)
+  search_index.put(documents)
+  logging.info('FTS indexed %d docs in shard %d', len(documents), shard_id)
+  # TODO(jrobbins): catch OverQuotaError and add the issues to the
+  # ReindexQueue table instead.
+
+
+def _ExtractCommentText(comment, users_by_id):
+  """Return a string with all the searchable text of the given Comment PB."""
+  commenter_email = users_by_id[comment.user_id].email
+  return '%s %s %s' % (
+      commenter_email,
+      comment.content,
+      ' '.join(attach.filename
+               for attach in comment.attachments
+               if not attach.deleted))
+
+
+def _BuildCustomFTSFields(issue):
+  """Return a list of FTS Fields to index string-valued custom fields."""
+  fts_fields = []
+  for fv in issue.field_values:
+    if fv.str_value:
+      # TODO(jrobbins): also indicate which were derived vs. explicit.
+      # TODO(jrobbins): also toss in the email addresses of any users in
+      # user-valued custom fields, ints for int-valued fields, etc.
+      fts_field = search.TextField(
+          name='custom_%d' % fv.field_id, value=fv.str_value)
+      fts_fields.append(fts_field)
+
+  return fts_fields
+
+
+def UnindexIssues(issue_ids):
+  """Remove many issues from the sharded search indexes."""
+  iids_by_shard = {}
+  for issue_id in issue_ids:
+    shard_id = issue_id % settings.num_logical_shards
+    iids_by_shard.setdefault(shard_id, [])
+    iids_by_shard[shard_id].append(issue_id)
+
+  for shard_id, iids_in_shard in iids_by_shard.items():
+    try:
+      logging.info(
+          'unindexing %r issue_ids in %r', len(iids_in_shard), shard_id)
+      search_index = search.Index(
+          name=settings.search_index_name_format % shard_id)
+      search_index.delete([str(iid) for iid in iids_in_shard])
+    except search.Error:
+      logging.exception('FTS deletion failed')
+
+
+def SearchIssueFullText(project_ids, query_ast_conj, shard_id):
+  """Do full-text search in GAE FTS.
+
+  Args:
+    project_ids: list of project ID numbers to consider.
+    query_ast_conj: One conjuctive clause from the AST parsed
+        from the user's query.
+    shard_id: int shard ID for the shard to consider.
+
+  Returns:
+    (issue_ids, capped) where issue_ids is a list of issue issue_ids that match
+    the full-text query.  And, capped is True if the results were capped due to
+    an implementation limitation.  Or, return (None, False) if the given AST
+    conjunction contains no full-text conditions.
+  """
+  fulltext_query = fulltext_helpers.BuildFTSQuery(
+      query_ast_conj, ISSUE_FULLTEXT_FIELDS)
+  if fulltext_query is None:
+    return None, False
+
+  if project_ids:
+    project_clause = ' OR '.join(
+        'project_id:%d' % pid for pid in project_ids)
+    fulltext_query = '(%s) %s' % (project_clause, fulltext_query)
+
+  # TODO(jrobbins): it would be good to also include some other
+  # structured search terms to narrow down the set of index
+  # documents considered.  E.g., most queries are only over the
+  # open issues.
+  logging.info('FTS query is %r', fulltext_query)
+  issue_ids = fulltext_helpers.ComprehensiveSearch(
+      fulltext_query, settings.search_index_name_format % shard_id)
+  capped = len(issue_ids) >= settings.fulltext_limit_per_shard
+  return issue_ids, capped