diff --git a/app.py b/app.py
index f4d900b15..c3b15d7aa 100644
--- a/app.py
+++ b/app.py
@@ -2,7 +2,7 @@ import logging
 import os
 import json
 
-from flask import Flask, Config, request, Request
+from flask import Flask, Config, request, Request, _request_ctx_stack
 from flask.ext.principal import Principal
 from flask.ext.login import LoginManager, UserMixin
 from flask.ext.mail import Mail
@@ -44,7 +44,6 @@ CONFIG_PROVIDER = FileConfigProvider(OVERRIDE_CONFIG_DIRECTORY, 'config.yaml', '
 
 app = Flask(__name__)
 logger = logging.getLogger(__name__)
-profile = logging.getLogger('profile')
 
 # Instantiate the default configuration (for test or for normal operation).
 if 'TEST' in os.environ:
@@ -79,21 +78,24 @@ class RequestWithId(Request):
 
 @app.before_request
 def _request_start():
-  profile.debug('Starting request: %s', request.path)
+  logger.debug('Starting request: %s', request.path)
 
 
 @app.after_request
 def _request_end(r):
-  profile.debug('Ending request: %s', request.path)
+  logger.debug('Ending request: %s', request.path)
   return r
 
 
 class InjectingFilter(logging.Filter):
   def filter(self, record):
-    record.msg = '[%s] %s' % (request.request_id, record.msg)
+    if _request_ctx_stack.top is not None:
+      record.msg = '[%s] %s' % (request.request_id, record.msg)
     return True
 
-profile.addFilter(InjectingFilter())
+# Add the request id filter to all handlers of the root logger
+for handler in logging.getLogger().handlers:
+  handler.addFilter(InjectingFilter())
 
 app.request_class = RequestWithId
 
diff --git a/application.py b/application.py
index a9bd0df6e..235a80b16 100644
--- a/application.py
+++ b/application.py
@@ -11,5 +11,5 @@ import registry
 
 
 if __name__ == '__main__':
-  logging.config.fileConfig('conf/logging.conf', disable_existing_loggers=False)
+  logging.config.fileConfig('conf/logging_debug.conf', disable_existing_loggers=False)
   application.run(port=5000, debug=True, threaded=True, host='0.0.0.0')
diff --git a/buildman/component/buildcomponent.py b/buildman/component/buildcomponent.py
index c1fb41a02..72caec215 100644
--- a/buildman/component/buildcomponent.py
+++ b/buildman/component/buildcomponent.py
@@ -10,7 +10,6 @@ from autobahn.wamp.exception import ApplicationError
 from buildman.server import BuildJobResult
 from buildman.component.basecomponent import BaseComponent
 from buildman.jobutil.buildjob import BuildJobLoadException
-from buildman.jobutil.buildpack import BuildPackage, BuildPackageException
 from buildman.jobutil.buildstatus import StatusHandler
 from buildman.jobutil.workererror import WorkerError
 
@@ -20,7 +19,7 @@ HEARTBEAT_DELTA = datetime.timedelta(seconds=30)
 HEARTBEAT_TIMEOUT = 10
 INITIAL_TIMEOUT = 25
 
-SUPPORTED_WORKER_VERSIONS = ['0.1-beta', '0.2']
+SUPPORTED_WORKER_VERSIONS = ['0.3']
 
 logger = logging.getLogger(__name__)
 
@@ -56,7 +55,10 @@ class BuildComponent(BaseComponent):
   def onJoin(self, details):
     logger.debug('Registering methods and listeners for component %s', self.builder_realm)
     yield trollius.From(self.register(self._on_ready, u'io.quay.buildworker.ready'))
+    yield trollius.From(self.register(self._determine_cache_tag,
+                                      u'io.quay.buildworker.determinecachetag'))
     yield trollius.From(self.register(self._ping, u'io.quay.buildworker.ping'))
+
     yield trollius.From(self.subscribe(self._on_heartbeat, 'io.quay.builder.heartbeat'))
     yield trollius.From(self.subscribe(self._on_log_message, 'io.quay.builder.logmessage'))
 
@@ -91,46 +93,6 @@ class BuildComponent(BaseComponent):
     buildpack_url = self.user_files.get_file_url(build_job.repo_build.resource_key,
                                                  requires_cors=False)
 
-    # TODO(jschorr): Remove as soon as the fleet has been transitioned to 0.2.
-    if self._worker_version == '0.1-beta':
-      # Retrieve the job's buildpack.
-      logger.debug('Retrieving build package: %s', buildpack_url)
-      buildpack = None
-      try:
-        buildpack = BuildPackage.from_url(buildpack_url)
-      except BuildPackageException as bpe:
-        self._build_failure('Could not retrieve build package', bpe)
-        raise trollius.Return()
-
-      # Extract the base image information from the Dockerfile.
-      parsed_dockerfile = None
-      logger.debug('Parsing dockerfile')
-
-      try:
-        parsed_dockerfile = buildpack.parse_dockerfile(build_config.get('build_subdir'))
-      except BuildPackageException as bpe:
-        self._build_failure('Could not find Dockerfile in build package', bpe)
-        raise trollius.Return()
-
-      image_and_tag_tuple = parsed_dockerfile.get_image_and_tag()
-      if image_and_tag_tuple is None or image_and_tag_tuple[0] is None:
-        self._build_failure('Missing FROM line in Dockerfile')
-        raise trollius.Return()
-
-      base_image_information = {
-          'repository': image_and_tag_tuple[0],
-          'tag': image_and_tag_tuple[1]
-      }
-
-      # Extract the number of steps from the Dockerfile.
-      with self._build_status as status_dict:
-        status_dict['total_commands'] = len(parsed_dockerfile.commands)
-    else:
-      # TODO(jschorr): This is a HACK to make sure the progress bar (sort of) continues working
-      # until such time as we have the caching code in place.
-      with self._build_status as status_dict:
-        status_dict['total_commands'] = 25
-
     # Add the pull robot information, if any.
     if build_job.pull_credentials:
       base_image_information['username'] = build_job.pull_credentials.get('username', '')
@@ -161,8 +123,7 @@ class BuildComponent(BaseComponent):
         'pull_token': build_job.repo_build.access_token.code,
         'push_token': build_job.repo_build.access_token.code,
         'tag_names': build_config.get('docker_tags', ['latest']),
-        'base_image': base_image_information,
-        'cached_tag': build_job.determine_cached_tag() or ''
+        'base_image': base_image_information
     }
 
     # Invoke the build.
@@ -256,6 +217,16 @@ class BuildComponent(BaseComponent):
     elif phase == BUILD_PHASE.BUILDING:
       self._build_status.append_log(current_status_string)
 
+  @trollius.coroutine
+  def _determine_cache_tag(self, command_comments, base_image_name, base_image_tag, base_image_id):
+    with self._build_status as status_dict:
+      status_dict['total_commands'] = len(command_comments) + 1
+
+    logger.debug('Checking cache on realm %s. Base image: %s:%s (%s)', self.builder_realm,
+                 base_image_name, base_image_tag, base_image_id)
+
+    tag_found = self._current_job.determine_cached_tag(base_image_id, command_comments)
+    raise trollius.Return(tag_found or '')
 
   def _build_failure(self, error_message, exception=None):
     """ Handles and logs a failed build. """
diff --git a/buildman/jobutil/buildjob.py b/buildman/jobutil/buildjob.py
index bb750fc38..1710c3aab 100644
--- a/buildman/jobutil/buildjob.py
+++ b/buildman/jobutil/buildjob.py
@@ -1,8 +1,12 @@
 import json
+import logging
 
 from cachetools import lru_cache
 from endpoints.notificationhelper import spawn_notification
 from data import model
+from util.imagetree import ImageTree
+
+logger = logging.getLogger(__name__)
 
 
 class BuildJobLoadException(Exception):
@@ -65,14 +69,65 @@ class BuildJob(object):
           'Could not parse repository build job config with ID %s' % self.job_details['build_uuid']
       )
 
-  def determine_cached_tag(self):
+  def determine_cached_tag(self, base_image_id=None, cache_comments=None):
     """ Returns the tag to pull to prime the cache or None if none. """
-    # TODO(jschorr): Change this to use the more complicated caching rules, once we have caching
-    # be a pull of things besides the constructed tags.
-    tags = self.build_config.get('docker_tags', ['latest'])
-    existing_tags = model.list_repository_tags(self.repo_build.repository.namespace_user.username,
-                                               self.repo_build.repository.name)
+    cached_tag = None
+    if base_image_id and cache_comments:
+      cached_tag = self._determine_cached_tag_by_comments(base_image_id, cache_comments)
 
+    if not cached_tag:
+      cached_tag = self._determine_cached_tag_by_tag()
+
+    logger.debug('Determined cached tag %s for %s: %s', cached_tag, base_image_id, cache_comments)
+
+    return cached_tag
+
+  def _determine_cached_tag_by_comments(self, base_image_id, cache_commands):
+    """ Determines the tag to use for priming the cache for this build job, by matching commands
+        starting at the given base_image_id. This mimics the Docker cache checking, so it should,
+        in theory, provide "perfect" caching.
+    """
+    # Lookup the base image in the repository. If it doesn't exist, nothing more to do.
+    repo_build = self.repo_build
+    repo_namespace = repo_build.repository.namespace_user.username
+    repo_name = repo_build.repository.name
+
+    base_image = model.get_image(repo_build.repository, base_image_id)
+    if base_image is None:
+      return None
+
+    # Build an in-memory tree of the full heirarchy of images in the repository.
+    all_images = model.get_repository_images(repo_namespace, repo_name)
+    all_tags = model.list_repository_tags(repo_namespace, repo_name)
+    tree = ImageTree(all_images, all_tags, base_filter=base_image.id)
+
+    # Find a path in the tree, starting at the base image, that matches the cache comments
+    # or some subset thereof.
+    def checker(step, image):
+      if step >= len(cache_commands):
+        return False
+
+      full_command = '["/bin/sh", "-c", "%s"]' % cache_commands[step]
+      logger.debug('Checking step #%s: %s, %s == %s', step, image.id,
+                   image.storage.command, full_command)
+
+      return image.storage.command == full_command
+
+    path = tree.find_longest_path(base_image.id, checker)
+    if not path:
+      return None
+
+    # Find any tag associated with the last image in the path.
+    return tree.tag_containing_image(path[-1])
+
+
+  def _determine_cached_tag_by_tag(self):
+    """ Determines the cached tag by looking for one of the tags being built, and seeing if it
+        exists in the repository. This is a fallback for when no comment information is available.
+    """
+    tags = self.build_config.get('docker_tags', ['latest'])
+    repository = self.repo_build.repository
+    existing_tags = model.list_repository_tags(repository.namespace_user.username, repository.name)
     cached_tags = set(tags) & set([tag.name for tag in existing_tags])
     if cached_tags:
       return list(cached_tags)[0]
diff --git a/buildman/jobutil/buildpack.py b/buildman/jobutil/buildpack.py
deleted file mode 100644
index 9892c65d3..000000000
--- a/buildman/jobutil/buildpack.py
+++ /dev/null
@@ -1,88 +0,0 @@
-import tarfile
-import requests
-import os
-
-from tempfile import TemporaryFile, mkdtemp
-from zipfile import ZipFile
-from util.dockerfileparse import parse_dockerfile
-from util.safetar import safe_extractall
-
-class BuildPackageException(Exception):
-  """ Exception raised when retrieving or parsing a build package. """
-  pass
-
-
-class BuildPackage(object):
-  """ Helper class for easy reading and updating of a Dockerfile build pack. """
-
-  def __init__(self, requests_file):
-    self._mime_processors = {
-        'application/zip': BuildPackage._prepare_zip,
-        'application/x-zip-compressed': BuildPackage._prepare_zip,
-        'text/plain': BuildPackage._prepare_dockerfile,
-        'application/octet-stream': BuildPackage._prepare_dockerfile,
-        'application/x-tar': BuildPackage._prepare_tarball,
-        'application/gzip': BuildPackage._prepare_tarball,
-        'application/x-gzip': BuildPackage._prepare_tarball,
-    }
-
-    c_type = requests_file.headers['content-type']
-    c_type = c_type.split(';')[0] if ';' in c_type else c_type
-
-    if c_type not in self._mime_processors:
-      raise BuildPackageException('Unknown build package mime type: %s' % c_type)
-
-    self._package_directory = None
-    try:
-      self._package_directory = self._mime_processors[c_type](requests_file)
-    except Exception as ex:
-      raise BuildPackageException(ex.message)
-
-  def parse_dockerfile(self, subdirectory):
-    dockerfile_path = os.path.join(self._package_directory, subdirectory, 'Dockerfile')
-    if not os.path.exists(dockerfile_path):
-      if subdirectory:
-        message = 'Build package did not contain a Dockerfile at sub directory %s.' % subdirectory
-      else:
-        message = 'Build package did not contain a Dockerfile at the root directory.'
-
-      raise BuildPackageException(message)
-
-    with open(dockerfile_path, 'r') as dockerfileobj:
-      return parse_dockerfile(dockerfileobj.read())
-
-  @staticmethod
-  def from_url(url):
-    buildpack_resource = requests.get(url, stream=True)
-    return BuildPackage(buildpack_resource)
-
-  @staticmethod
-  def _prepare_zip(request_file):
-    build_dir = mkdtemp(prefix='docker-build-')
-
-    # Save the zip file to temp somewhere
-    with TemporaryFile() as zip_file:
-      zip_file.write(request_file.content)
-      to_extract = ZipFile(zip_file)
-      to_extract.extractall(build_dir)
-
-    return build_dir
-
-  @staticmethod
-  def _prepare_dockerfile(request_file):
-    build_dir = mkdtemp(prefix='docker-build-')
-    dockerfile_path = os.path.join(build_dir, "Dockerfile")
-    with open(dockerfile_path, 'w') as dockerfile:
-      dockerfile.write(request_file.content)
-
-    return build_dir
-
-  @staticmethod
-  def _prepare_tarball(request_file):
-    build_dir = mkdtemp(prefix='docker-build-')
-
-    # Save the zip file to temp somewhere
-    with tarfile.open(mode='r|*', fileobj=request_file.raw) as tar_stream:
-      safe_extractall(tar_stream, build_dir)
-
-    return build_dir
diff --git a/buildman/jobutil/buildstatus.py b/buildman/jobutil/buildstatus.py
index 217e3aa6c..2ae127ee0 100644
--- a/buildman/jobutil/buildstatus.py
+++ b/buildman/jobutil/buildstatus.py
@@ -7,11 +7,12 @@ class StatusHandler(object):
 
   def __init__(self, build_logs, repository_build_uuid):
     self._current_phase = None
+    self._current_command = None
     self._uuid = repository_build_uuid
     self._build_logs = build_logs
 
     self._status = {
-        'total_commands': None,
+        'total_commands': 0,
         'current_command': None,
         'push_completion': 0.0,
         'pull_completion': 0.0,
@@ -26,9 +27,16 @@ class StatusHandler(object):
     self._build_logs.append_log_message(self._uuid, log_message, log_type, log_data)
 
   def append_log(self, log_message, extra_data=None):
+    if log_message is None:
+      return
+
     self._append_log_message(log_message, log_data=extra_data)
 
   def set_command(self, command, extra_data=None):
+    if self._current_command == command:
+      return
+
+    self._current_command = command
     self._append_log_message(command, self._build_logs.COMMAND, extra_data)
 
   def set_error(self, error_message, extra_data=None, internal_error=False):
diff --git a/buildman/jobutil/workererror.py b/buildman/jobutil/workererror.py
index c7100360b..fdf6503b0 100644
--- a/buildman/jobutil/workererror.py
+++ b/buildman/jobutil/workererror.py
@@ -63,6 +63,11 @@ class WorkerError(object):
         'io.quay.builder.missingorinvalidargument': {
             'message': 'Missing required arguments for builder',
             'is_internal': True
+        },
+
+        'io.quay.builder.cachelookupissue': {
+            'message': 'Error checking for a cached tag',
+            'is_internal': True
         }
     }
 
diff --git a/buildman/manager/executor.py b/buildman/manager/executor.py
index 92641c6ce..035d5cdf8 100644
--- a/buildman/manager/executor.py
+++ b/buildman/manager/executor.py
@@ -11,6 +11,7 @@ from trollius import coroutine, From, Return, get_event_loop
 from functools import partial
 
 from buildman.asyncutil import AsyncWrapper
+from container_cloud_config import CloudConfigContext
 
 
 logger = logging.getLogger(__name__)
@@ -20,7 +21,7 @@ ONE_HOUR = 60*60
 
 ENV = Environment(loader=FileSystemLoader('buildman/templates'))
 TEMPLATE = ENV.get_template('cloudconfig.yaml')
-
+CloudConfigContext().populate_jinja_environment(ENV)
 
 class ExecutorException(Exception):
   """ Exception raised when there is a problem starting or stopping a builder.
diff --git a/buildman/templates/cloudconfig.yaml b/buildman/templates/cloudconfig.yaml
index 13e6894bf..51bb2f090 100644
--- a/buildman/templates/cloudconfig.yaml
+++ b/buildman/templates/cloudconfig.yaml
@@ -19,18 +19,13 @@ coreos:
     group: {{ coreos_channel }}
 
   units:
-    - name: quay-builder.service
-      command: start
-      content: |
-        [Unit]
-        Description=Quay builder container
-        Author=Jake Moshenko
-        After=docker.service
-
-        [Service]
-        TimeoutStartSec=600
-        TimeoutStopSec=2000
-        ExecStartPre=/usr/bin/docker login -u {{ quay_username }} -p {{ quay_password }} -e unused quay.io
-        ExecStart=/usr/bin/docker run --rm --net=host --name quay-builder --privileged --env-file /root/overrides.list -v /var/run/docker.sock:/var/run/docker.sock -v /usr/share/ca-certificates:/etc/ssl/certs quay.io/coreos/registry-build-worker:{{ worker_tag }}
-        ExecStop=/usr/bin/docker stop quay-builder
-        ExecStopPost=/bin/sh -xc "/bin/sleep 120; /usr/bin/systemctl --no-block poweroff"
+    {{ dockersystemd('quay-builder',
+                     'quay.io/coreos/registry-build-worker',
+                     quay_username,
+                     quay_password,
+                     worker_tag,
+                     extra_args='--net=host --privileged --env-file /root/overrides.list -v /var/run/docker.sock:/var/run/docker.sock -v /usr/share/ca-certificates:/etc/ssl/certs',
+                     exec_stop_post=['/bin/sh -xc "/bin/sleep 120; /usr/bin/systemctl --no-block poweroff"'],
+                     flattened=True,
+                     restart_policy='no'
+                    ) | indent(4) }}
diff --git a/conf/gunicorn_local.py b/conf/gunicorn_local.py
index e17be0bb3..6987041be 100644
--- a/conf/gunicorn_local.py
+++ b/conf/gunicorn_local.py
@@ -3,6 +3,6 @@ workers = 2
 worker_class = 'gevent'
 timeout = 2000
 daemon = False
-logconfig = 'conf/logging.conf'
+logconfig = 'conf/logging_debug.conf'
 pythonpath = '.'
 preload_app = True
diff --git a/conf/logging.conf b/conf/logging.conf
index d009f08ee..317803a24 100644
--- a/conf/logging.conf
+++ b/conf/logging.conf
@@ -1,5 +1,5 @@
 [loggers]
-keys=root, gunicorn.error, gunicorn.access, application.profiler, boto, werkzeug
+keys=root
 
 [handlers]
 keys=console
@@ -7,39 +7,9 @@ keys=console
 [formatters]
 keys=generic
 
-[logger_application.profiler]
-level=DEBUG
-handlers=console
-propagate=0
-qualname=application.profiler
-
 [logger_root]
-level=DEBUG
-handlers=console
-
-[logger_boto]
 level=INFO
 handlers=console
-propagate=0
-qualname=boto
-
-[logger_werkzeug]
-level=DEBUG
-handlers=console
-propagate=0
-qualname=werkzeug
-
-[logger_gunicorn.error]
-level=INFO
-handlers=console
-propagate=1
-qualname=gunicorn.error
-
-[logger_gunicorn.access]
-level=INFO
-handlers=console
-propagate=0
-qualname=gunicorn.access
 
 [handler_console]
 class=StreamHandler
diff --git a/conf/logging_debug.conf b/conf/logging_debug.conf
new file mode 100644
index 000000000..01a3c8fbb
--- /dev/null
+++ b/conf/logging_debug.conf
@@ -0,0 +1,21 @@
+[loggers]
+keys=root
+
+[handlers]
+keys=console
+
+[formatters]
+keys=generic
+
+[logger_root]
+level=DEBUG
+handlers=console
+
+[handler_console]
+class=StreamHandler
+formatter=generic
+args=(sys.stdout, )
+
+[formatter_generic]
+format=%(asctime)s [%(process)d] [%(levelname)s] [%(name)s] %(message)s
+class=logging.Formatter
diff --git a/data/model/legacy.py b/data/model/legacy.py
index 9bae8cd32..ff1a5ba59 100644
--- a/data/model/legacy.py
+++ b/data/model/legacy.py
@@ -1096,6 +1096,26 @@ def get_repository(namespace_name, repository_name):
     return None
 
 
+def get_image(repo, dockerfile_id):
+  try:
+    return Image.get(Image.docker_image_id == dockerfile_id, Image.repository == repo)
+  except Image.DoesNotExist:
+    return None
+
+
+def find_child_image(repo, parent_image, command):
+  try:
+    return (Image.select()
+                .join(ImageStorage)
+                .switch(Image)
+                .where(Image.ancestors % '%/' + parent_image.id + '/%',
+                       ImageStorage.command == command)
+                .order_by(ImageStorage.created.desc())
+                .get())
+  except Image.DoesNotExist:
+    return None
+
+
 def get_repo_image(namespace_name, repository_name, docker_image_id):
   def limit_to_image_id(query):
     return query.where(Image.docker_image_id == docker_image_id).limit(1)
@@ -1681,7 +1701,6 @@ def get_tag_image(namespace_name, repository_name, tag_name):
   else:
     return images[0]
 
-
 def get_image_by_id(namespace_name, repository_name, docker_image_id):
   image = get_repo_image_extended(namespace_name, repository_name, docker_image_id)
   if not image:
diff --git a/endpoints/common.py b/endpoints/common.py
index 3534ee072..9301329e0 100644
--- a/endpoints/common.py
+++ b/endpoints/common.py
@@ -29,7 +29,6 @@ from endpoints.notificationhelper import spawn_notification
 import features
 
 logger = logging.getLogger(__name__)
-profile = logging.getLogger('application.profiler')
 
 route_data = None
 
@@ -253,7 +252,7 @@ def start_build(repository, dockerfile_id, tags, build_name, subdir, manual,
                    metadata=metadata, repository=repository)
 
   # Add notifications for the build queue.
-  profile.debug('Adding notifications for repository')
+  logger.debug('Adding notifications for repository')
   event_data = {
     'build_id': build_request.uuid,
     'build_name': build_name,
diff --git a/endpoints/index.py b/endpoints/index.py
index de45f2fde..660ab94aa 100644
--- a/endpoints/index.py
+++ b/endpoints/index.py
@@ -23,7 +23,6 @@ from endpoints.notificationhelper import spawn_notification
 import features
 
 logger = logging.getLogger(__name__)
-profile = logging.getLogger('application.profiler')
 
 index = Blueprint('index', __name__)
 
@@ -120,7 +119,7 @@ def create_user():
 
   else:
     # New user case
-    profile.debug('Creating user')
+    logger.debug('Creating user')
     new_user = None
 
     try:
@@ -128,10 +127,10 @@ def create_user():
     except model.TooManyUsersException as ex:
       abort(402, 'Seat limit has been reached for this license', issue='seat-limit')
 
-    profile.debug('Creating email code for user')
+    logger.debug('Creating email code for user')
     code = model.create_confirm_email_code(new_user)
 
-    profile.debug('Sending email code to user')
+    logger.debug('Sending email code to user')
     send_confirmation_email(new_user.username, new_user.email, code.code)
 
     return make_response('Created', 201)
@@ -168,12 +167,12 @@ def update_user(username):
     update_request = request.get_json()
 
     if 'password' in update_request:
-      profile.debug('Updating user password')
+      logger.debug('Updating user password')
       model.change_password(get_authenticated_user(),
                             update_request['password'])
 
     if 'email' in update_request:
-      profile.debug('Updating user email')
+      logger.debug('Updating user email')
       model.update_email(get_authenticated_user(), update_request['email'])
 
     return jsonify({
@@ -189,13 +188,13 @@ def update_user(username):
 @parse_repository_name
 @generate_headers(role='write')
 def create_repository(namespace, repository):
-  profile.debug('Parsing image descriptions')
+  logger.debug('Parsing image descriptions')
   image_descriptions = json.loads(request.data.decode('utf8'))
 
-  profile.debug('Looking up repository')
+  logger.debug('Looking up repository')
   repo = model.get_repository(namespace, repository)
 
-  profile.debug('Repository looked up')
+  logger.debug('Repository looked up')
   if not repo and get_authenticated_user() is None:
     logger.debug('Attempt to create new repository without user auth.')
     abort(401,
@@ -219,11 +218,11 @@ def create_repository(namespace, repository):
             issue='no-create-permission',
             namespace=namespace)
 
-    profile.debug('Creaing repository with owner: %s', get_authenticated_user().username)
+    logger.debug('Creaing repository with owner: %s', get_authenticated_user().username)
     repo = model.create_repository(namespace, repository,
                                    get_authenticated_user())
 
-  profile.debug('Determining already added images')
+  logger.debug('Determining already added images')
   added_images = OrderedDict([(desc['id'], desc) for desc in image_descriptions])
   new_repo_images = dict(added_images)
 
@@ -239,7 +238,7 @@ def create_repository(namespace, repository):
     for existing in existing_images:
       added_images.pop(existing.docker_image_id)
 
-  profile.debug('Creating/Linking necessary images')
+  logger.debug('Creating/Linking necessary images')
   username = get_authenticated_user() and get_authenticated_user().username
   translations = {}
   for image_description in added_images.values():
@@ -247,7 +246,7 @@ def create_repository(namespace, repository):
                                     translations, storage.preferred_locations[0])
 
 
-  profile.debug('Created images')
+  logger.debug('Created images')
   track_and_log('push_repo', repo)
   return make_response('Created', 201)
 
@@ -260,14 +259,14 @@ def update_images(namespace, repository):
   permission = ModifyRepositoryPermission(namespace, repository)
 
   if permission.can():
-    profile.debug('Looking up repository')
+    logger.debug('Looking up repository')
     repo = model.get_repository(namespace, repository)
     if not repo:
       # Make sure the repo actually exists.
       abort(404, message='Unknown repository', issue='unknown-repo')
 
     if get_authenticated_user():
-      profile.debug('Publishing push event')
+      logger.debug('Publishing push event')
       username = get_authenticated_user().username
 
       # Mark that the user has pushed the repo.
@@ -280,11 +279,11 @@ def update_images(namespace, repository):
       event = userevents.get_event(username)
       event.publish_event_data('docker-cli', user_data)
 
-    profile.debug('GCing repository')
+    logger.debug('GCing repository')
     num_removed = model.garbage_collect_repository(namespace, repository)
 
     # Generate a job for each notification that has been added to this repo
-    profile.debug('Adding notifications for repository')
+    logger.debug('Adding notifications for repository')
 
     updated_tags = session.get('pushed_tags', {})
     event_data = {
@@ -307,13 +306,13 @@ def get_repository_images(namespace, repository):
   # TODO invalidate token?
   if permission.can() or model.repository_is_public(namespace, repository):
     # We can't rely on permissions to tell us if a repo exists anymore
-    profile.debug('Looking up repository')
+    logger.debug('Looking up repository')
     repo = model.get_repository(namespace, repository)
     if not repo:
       abort(404, message='Unknown repository', issue='unknown-repo')
 
     all_images = []
-    profile.debug('Retrieving repository images')
+    logger.debug('Retrieving repository images')
     for image in model.get_repository_images(namespace, repository):
       new_image_view = {
         'id': image.docker_image_id,
@@ -321,7 +320,7 @@ def get_repository_images(namespace, repository):
       }
       all_images.append(new_image_view)
 
-    profile.debug('Building repository image response')
+    logger.debug('Building repository image response')
     resp = make_response(json.dumps(all_images), 200)
     resp.mimetype = 'application/json'
 
diff --git a/endpoints/registry.py b/endpoints/registry.py
index b4b03334f..5178f3a83 100644
--- a/endpoints/registry.py
+++ b/endpoints/registry.py
@@ -20,7 +20,6 @@ from util import gzipstream
 registry = Blueprint('registry', __name__)
 
 logger = logging.getLogger(__name__)
-profile = logging.getLogger('application.profiler')
 
 class SocketReader(object):
   def __init__(self, fp):
@@ -100,12 +99,12 @@ def set_cache_headers(f):
 def head_image_layer(namespace, repository, image_id, headers):
   permission = ReadRepositoryPermission(namespace, repository)
 
-  profile.debug('Checking repo permissions')
+  logger.debug('Checking repo permissions')
   if permission.can() or model.repository_is_public(namespace, repository):
-    profile.debug('Looking up repo image')
+    logger.debug('Looking up repo image')
     repo_image = model.get_repo_image_extended(namespace, repository, image_id)
     if not repo_image:
-      profile.debug('Image not found')
+      logger.debug('Image not found')
       abort(404, 'Image %(image_id)s not found', issue='unknown-image',
             image_id=image_id)
 
@@ -114,7 +113,7 @@ def head_image_layer(namespace, repository, image_id, headers):
     # Add the Accept-Ranges header if the storage engine supports resumable
     # downloads.
     if store.get_supports_resumable_downloads(repo_image.storage.locations):
-      profile.debug('Storage supports resumable downloads')
+      logger.debug('Storage supports resumable downloads')
       extra_headers['Accept-Ranges'] = 'bytes'
 
     resp = make_response('')
@@ -133,35 +132,35 @@ def head_image_layer(namespace, repository, image_id, headers):
 def get_image_layer(namespace, repository, image_id, headers):
   permission = ReadRepositoryPermission(namespace, repository)
 
-  profile.debug('Checking repo permissions')
+  logger.debug('Checking repo permissions')
   if permission.can() or model.repository_is_public(namespace, repository):
-    profile.debug('Looking up repo image')
+    logger.debug('Looking up repo image')
     repo_image = model.get_repo_image_extended(namespace, repository, image_id)
     if not repo_image:
-      profile.debug('Image not found')
+      logger.debug('Image not found')
       abort(404, 'Image %(image_id)s not found', issue='unknown-image',
             image_id=image_id)
 
-    profile.debug('Looking up the layer path')
+    logger.debug('Looking up the layer path')
     try:
       path = store.image_layer_path(repo_image.storage.uuid)
 
-      profile.debug('Looking up the direct download URL')
+      logger.debug('Looking up the direct download URL')
       direct_download_url = store.get_direct_download_url(repo_image.storage.locations, path)
 
       if direct_download_url:
-        profile.debug('Returning direct download URL')
+        logger.debug('Returning direct download URL')
         resp = redirect(direct_download_url)
         return resp
 
-      profile.debug('Streaming layer data')
+      logger.debug('Streaming layer data')
 
       # Close the database handle here for this process before we send the long download.
       database.close_db_filter(None)
 
       return Response(store.stream_read(repo_image.storage.locations, path), headers=headers)
     except (IOError, AttributeError):
-      profile.exception('Image layer data not found')
+      logger.exception('Image layer data not found')
       abort(404, 'Image %(image_id)s not found', issue='unknown-image',
             image_id=image_id)
 
@@ -172,30 +171,30 @@ def get_image_layer(namespace, repository, image_id, headers):
 @process_auth
 @extract_namespace_repo_from_session
 def put_image_layer(namespace, repository, image_id):
-  profile.debug('Checking repo permissions')
+  logger.debug('Checking repo permissions')
   permission = ModifyRepositoryPermission(namespace, repository)
   if not permission.can():
     abort(403)
 
-  profile.debug('Retrieving image')
+  logger.debug('Retrieving image')
   repo_image = model.get_repo_image_extended(namespace, repository, image_id)
   try:
-    profile.debug('Retrieving image data')
+    logger.debug('Retrieving image data')
     uuid = repo_image.storage.uuid
     json_data = store.get_content(repo_image.storage.locations, store.image_json_path(uuid))
   except (IOError, AttributeError):
-    profile.exception('Exception when retrieving image data')
+    logger.exception('Exception when retrieving image data')
     abort(404, 'Image %(image_id)s not found', issue='unknown-image',
           image_id=image_id)
 
-  profile.debug('Retrieving image path info')
+  logger.debug('Retrieving image path info')
   layer_path = store.image_layer_path(uuid)
 
   if (store.exists(repo_image.storage.locations, layer_path) and not
       image_is_uploading(repo_image)):
     exact_abort(409, 'Image already exists')
 
-  profile.debug('Storing layer data')
+  logger.debug('Storing layer data')
 
   input_stream = request.stream
   if request.headers.get('transfer-encoding') == 'chunked':
@@ -262,7 +261,7 @@ def put_image_layer(namespace, repository, image_id):
 
   # The layer is ready for download, send a job to the work queue to
   # process it.
-  profile.debug('Adding layer to diff queue')
+  logger.debug('Adding layer to diff queue')
   repo = model.get_repository(namespace, repository)
   image_diff_queue.put([repo.namespace_user.username, repository, image_id], json.dumps({
     'namespace_user_id': repo.namespace_user.id,
@@ -277,7 +276,7 @@ def put_image_layer(namespace, repository, image_id):
 @process_auth
 @extract_namespace_repo_from_session
 def put_image_checksum(namespace, repository, image_id):
-  profile.debug('Checking repo permissions')
+  logger.debug('Checking repo permissions')
   permission = ModifyRepositoryPermission(namespace, repository)
   if not permission.can():
     abort(403)
@@ -303,23 +302,23 @@ def put_image_checksum(namespace, repository, image_id):
     abort(400, 'Checksum not found in Cookie for image %(image_id)s',
           issue='missing-checksum-cookie', image_id=image_id)
 
-  profile.debug('Looking up repo image')
+  logger.debug('Looking up repo image')
   repo_image = model.get_repo_image_extended(namespace, repository, image_id)
   if not repo_image or not repo_image.storage:
     abort(404, 'Image not found: %(image_id)s', issue='unknown-image', image_id=image_id)
 
   uuid = repo_image.storage.uuid
 
-  profile.debug('Looking up repo layer data')
+  logger.debug('Looking up repo layer data')
   if not store.exists(repo_image.storage.locations, store.image_json_path(uuid)):
     abort(404, 'Image not found: %(image_id)s', issue='unknown-image', image_id=image_id)
 
-  profile.debug('Marking image path')
+  logger.debug('Marking image path')
   if not image_is_uploading(repo_image):
     abort(409, 'Cannot set checksum for image %(image_id)s',
           issue='image-write-error', image_id=image_id)
 
-  profile.debug('Storing image checksum')
+  logger.debug('Storing image checksum')
   err = store_checksum(repo_image.storage, checksum)
   if err:
     abort(400, err)
@@ -336,7 +335,7 @@ def put_image_checksum(namespace, repository, image_id):
 
   # The layer is ready for download, send a job to the work queue to
   # process it.
-  profile.debug('Adding layer to diff queue')
+  logger.debug('Adding layer to diff queue')
   repo = model.get_repository(namespace, repository)
   image_diff_queue.put([repo.namespace_user.username, repository, image_id], json.dumps({
     'namespace_user_id': repo.namespace_user.id,
@@ -353,23 +352,23 @@ def put_image_checksum(namespace, repository, image_id):
 @require_completion
 @set_cache_headers
 def get_image_json(namespace, repository, image_id, headers):
-  profile.debug('Checking repo permissions')
+  logger.debug('Checking repo permissions')
   permission = ReadRepositoryPermission(namespace, repository)
   if not permission.can() and not model.repository_is_public(namespace,
                                                              repository):
     abort(403)
 
-  profile.debug('Looking up repo image')
+  logger.debug('Looking up repo image')
   repo_image = model.get_repo_image_extended(namespace, repository, image_id)
 
-  profile.debug('Looking up repo layer data')
+  logger.debug('Looking up repo layer data')
   try:
     uuid = repo_image.storage.uuid
     data = store.get_content(repo_image.storage.locations, store.image_json_path(uuid))
   except (IOError, AttributeError):
     flask_abort(404)
 
-  profile.debug('Looking up repo layer size')
+  logger.debug('Looking up repo layer size')
   size = repo_image.storage.image_size
   headers['X-Docker-Size'] = str(size)
 
@@ -384,16 +383,16 @@ def get_image_json(namespace, repository, image_id, headers):
 @require_completion
 @set_cache_headers
 def get_image_ancestry(namespace, repository, image_id, headers):
-  profile.debug('Checking repo permissions')
+  logger.debug('Checking repo permissions')
   permission = ReadRepositoryPermission(namespace, repository)
   if not permission.can() and not model.repository_is_public(namespace,
                                                              repository):
     abort(403)
 
-  profile.debug('Looking up repo image')
+  logger.debug('Looking up repo image')
   repo_image = model.get_repo_image_extended(namespace, repository, image_id)
 
-  profile.debug('Looking up image data')
+  logger.debug('Looking up image data')
   try:
     uuid = repo_image.storage.uuid
     data = store.get_content(repo_image.storage.locations, store.image_ancestry_path(uuid))
@@ -401,11 +400,11 @@ def get_image_ancestry(namespace, repository, image_id, headers):
     abort(404, 'Image %(image_id)s not found', issue='unknown-image',
           image_id=image_id)
 
-  profile.debug('Converting to <-> from JSON')
+  logger.debug('Converting to <-> from JSON')
   response = make_response(json.dumps(json.loads(data)), 200)
   response.headers.extend(headers)
 
-  profile.debug('Done')
+  logger.debug('Done')
   return response
 
 
@@ -435,12 +434,12 @@ def store_checksum(image_storage, checksum):
 @process_auth
 @extract_namespace_repo_from_session
 def put_image_json(namespace, repository, image_id):
-  profile.debug('Checking repo permissions')
+  logger.debug('Checking repo permissions')
   permission = ModifyRepositoryPermission(namespace, repository)
   if not permission.can():
     abort(403)
 
-  profile.debug('Parsing image JSON')
+  logger.debug('Parsing image JSON')
   try:
     data = json.loads(request.data.decode('utf8'))
   except ValueError:
@@ -454,10 +453,10 @@ def put_image_json(namespace, repository, image_id):
     abort(400, 'Missing key `id` in JSON for image: %(image_id)s',
           issue='invalid-request', image_id=image_id)
 
-  profile.debug('Looking up repo image')
+  logger.debug('Looking up repo image')
   repo_image = model.get_repo_image_extended(namespace, repository, image_id)
   if not repo_image:
-    profile.debug('Image not found')
+    logger.debug('Image not found')
     abort(404, 'Image %(image_id)s not found', issue='unknown-image',
           image_id=image_id)
 
@@ -471,24 +470,24 @@ def put_image_json(namespace, repository, image_id):
 
   parent_image = None
   if parent_id:
-    profile.debug('Looking up parent image')
+    logger.debug('Looking up parent image')
     parent_image = model.get_repo_image_extended(namespace, repository, parent_id)
 
   parent_uuid = parent_image and parent_image.storage.uuid
   parent_locations = parent_image and parent_image.storage.locations
 
   if parent_id:
-    profile.debug('Looking up parent image data')
+    logger.debug('Looking up parent image data')
 
   if (parent_id and not
       store.exists(parent_locations, store.image_json_path(parent_uuid))):
     abort(400, 'Image %(image_id)s depends on non existing parent image %(parent_id)s',
           issue='invalid-request', image_id=image_id, parent_id=parent_id)
 
-  profile.debug('Looking up image storage paths')
+  logger.debug('Looking up image storage paths')
   json_path = store.image_json_path(uuid)
 
-  profile.debug('Checking if image already exists')
+  logger.debug('Checking if image already exists')
   if (store.exists(repo_image.storage.locations, json_path) and not
       image_is_uploading(repo_image)):
     exact_abort(409, 'Image already exists')
@@ -501,24 +500,24 @@ def put_image_json(namespace, repository, image_id):
   command_list = data.get('container_config', {}).get('Cmd', None)
   command = json.dumps(command_list) if command_list else None
 
-  profile.debug('Setting image metadata')
+  logger.debug('Setting image metadata')
   model.set_image_metadata(image_id, namespace, repository,
                            data.get('created'), data.get('comment'), command,
                            parent_image)
 
-  profile.debug('Putting json path')
+  logger.debug('Putting json path')
   store.put_content(repo_image.storage.locations, json_path, request.data)
 
-  profile.debug('Generating image ancestry')
+  logger.debug('Generating image ancestry')
 
   try:
     generate_ancestry(image_id, uuid, repo_image.storage.locations, parent_id, parent_uuid,
                       parent_locations)
   except IOError as ioe:
-    profile.debug('Error when generating ancestry: %s' % ioe.message)
+    logger.debug('Error when generating ancestry: %s' % ioe.message)
     abort(404)
 
-  profile.debug('Done')
+  logger.debug('Done')
   return make_response('true', 200)
 
 
diff --git a/endpoints/trackhelper.py b/endpoints/trackhelper.py
index 83b9d4270..fb99a2c2d 100644
--- a/endpoints/trackhelper.py
+++ b/endpoints/trackhelper.py
@@ -6,7 +6,6 @@ from flask import request
 from auth.auth_context import get_authenticated_user, get_validated_token, get_validated_oauth_token
 
 logger = logging.getLogger(__name__)
-profile = logging.getLogger('application.profiler')
 
 def track_and_log(event_name, repo, **kwargs):
   repository = repo.name
@@ -23,7 +22,7 @@ def track_and_log(event_name, repo, **kwargs):
   authenticated_user = get_authenticated_user()
   authenticated_token = get_validated_token() if not authenticated_user else None
 
-  profile.debug('Logging the %s to Mixpanel and the log system', event_name)
+  logger.debug('Logging the %s to Mixpanel and the log system', event_name)
   if authenticated_oauth_token:
     metadata['oauth_token_id'] = authenticated_oauth_token.id
     metadata['oauth_token_application_id'] = authenticated_oauth_token.application.client_id
@@ -45,9 +44,9 @@ def track_and_log(event_name, repo, **kwargs):
   }
 
   # Publish the user event (if applicable)
-  profile.debug('Checking publishing %s to the user events system', event_name)
+  logger.debug('Checking publishing %s to the user events system', event_name)
   if authenticated_user:
-    profile.debug('Publishing %s to the user events system', event_name)
+    logger.debug('Publishing %s to the user events system', event_name)
     user_event_data = {
       'action': event_name,
       'repository': repository,
@@ -58,14 +57,14 @@ def track_and_log(event_name, repo, **kwargs):
     event.publish_event_data('docker-cli', user_event_data)
 
   # Save the action to mixpanel.
-  profile.debug('Logging the %s to Mixpanel', event_name)
+  logger.debug('Logging the %s to Mixpanel', event_name)
   analytics.track(analytics_id, event_name, extra_params)
 
   # Log the action to the database.
-  profile.debug('Logging the %s to logs system', event_name)
+  logger.debug('Logging the %s to logs system', event_name)
   model.log_action(event_name, namespace,
                    performer=authenticated_user,
                    ip=request.remote_addr, metadata=metadata,
                    repository=repo)
 
-  profile.debug('Track and log of %s complete', event_name)
+  logger.debug('Track and log of %s complete', event_name)
diff --git a/requirements-nover.txt b/requirements-nover.txt
index f010531a2..9b8707870 100644
--- a/requirements-nover.txt
+++ b/requirements-nover.txt
@@ -40,6 +40,7 @@ git+https://github.com/DevTable/aniso8601-fake.git
 git+https://github.com/DevTable/anunidecode.git
 git+https://github.com/DevTable/avatar-generator.git
 git+https://github.com/DevTable/pygithub.git
+git+https://github.com/DevTable/container-cloud-config.git
 git+https://github.com/jplana/python-etcd.git
 gipc
 pyOpenSSL
diff --git a/requirements.txt b/requirements.txt
index f43c700c8..4e51c6245 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -64,5 +64,6 @@ git+https://github.com/DevTable/aniso8601-fake.git
 git+https://github.com/DevTable/anunidecode.git
 git+https://github.com/DevTable/avatar-generator.git
 git+https://github.com/DevTable/pygithub.git
+git+https://github.com/DevTable/container-cloud-config.git
 git+https://github.com/NateFerrero/oauth2lib.git
 git+https://github.com/jplana/python-etcd.git
diff --git a/test/test_imagetree.py b/test/test_imagetree.py
new file mode 100644
index 000000000..d72eb6505
--- /dev/null
+++ b/test/test_imagetree.py
@@ -0,0 +1,96 @@
+import unittest
+
+from app import app
+from util.imagetree import ImageTree
+from initdb import setup_database_for_testing, finished_database_for_testing
+from data import model
+
+NAMESPACE = 'devtable'
+SIMPLE_REPO = 'simple'
+COMPLEX_REPO = 'complex'
+
+class TestImageTree(unittest.TestCase):
+  def setUp(self):
+    setup_database_for_testing(self)
+    self.app = app.test_client()
+    self.ctx = app.test_request_context()
+    self.ctx.__enter__()
+
+  def tearDown(self):
+    finished_database_for_testing(self)
+    self.ctx.__exit__(True, None, None)
+
+  def _get_base_image(self, all_images):
+    for image in all_images:
+      if image.ancestors == '/':
+        return image
+
+    return None
+
+  def test_longest_path_simple_repo(self):
+    all_images = list(model.get_repository_images(NAMESPACE, SIMPLE_REPO))
+    all_tags = list(model.list_repository_tags(NAMESPACE, SIMPLE_REPO))
+    tree = ImageTree(all_images, all_tags)
+
+    base_image = self._get_base_image(all_images)
+    tag_image = all_tags[0].image
+
+    def checker(index, image):
+      return True
+
+    ancestors = tag_image.ancestors.split('/')[2:-1] # Skip the first image.
+    result = tree.find_longest_path(base_image.id, checker)
+    self.assertEquals(3, len(result))
+    for index in range(0, 2):
+      self.assertEquals(int(ancestors[index]), result[index].id)
+
+    self.assertEquals('latest', tree.tag_containing_image(result[-1]))
+
+  def test_longest_path_complex_repo(self):
+    all_images = list(model.get_repository_images(NAMESPACE, COMPLEX_REPO))
+    all_tags = list(model.list_repository_tags(NAMESPACE, COMPLEX_REPO))
+    tree = ImageTree(all_images, all_tags)
+
+    base_image = self._get_base_image(all_images)
+
+    def checker(index, image):
+      return True
+
+    result = tree.find_longest_path(base_image.id, checker)
+    self.assertEquals(4, len(result))
+    self.assertEquals('v2.0', tree.tag_containing_image(result[-1]))
+
+  def test_filtering(self):
+    all_images = list(model.get_repository_images(NAMESPACE, COMPLEX_REPO))
+    all_tags = list(model.list_repository_tags(NAMESPACE, COMPLEX_REPO))
+    tree = ImageTree(all_images, all_tags, base_filter=1245)
+
+    base_image = self._get_base_image(all_images)
+
+    def checker(index, image):
+      return True
+
+    result = tree.find_longest_path(base_image.id, checker)
+    self.assertEquals(0, len(result))
+
+  def test_find_tag_parent_image(self):
+    all_images = list(model.get_repository_images(NAMESPACE, COMPLEX_REPO))
+    all_tags = list(model.list_repository_tags(NAMESPACE, COMPLEX_REPO))
+    tree = ImageTree(all_images, all_tags)
+
+    base_image = self._get_base_image(all_images)
+
+    def checker(index, image):
+      return True
+
+    result = tree.find_longest_path(base_image.id, checker)
+    self.assertEquals(4, len(result))
+
+    # Only use the first two images. They don't have tags, but the method should
+    # still return the tag that contains them.
+    self.assertEquals('v2.0', tree.tag_containing_image(result[0]))
+
+
+if __name__ == '__main__':
+  unittest.main()
+
diff --git a/util/imagetree.py b/util/imagetree.py
new file mode 100644
index 000000000..39cd5c3c9
--- /dev/null
+++ b/util/imagetree.py
@@ -0,0 +1,103 @@
+class ImageTreeNode(object):
+  """ A node in the image tree. """
+  def __init__(self, image):
+    self.image = image
+    self.parent = None
+    self.children = []
+    self.tags = []
+
+  def add_child(self, child):
+    self.children.append(child)
+    child.parent = self
+
+  def add_tag(self, tag):
+    self.tags.append(tag)
+
+
+class ImageTree(object):
+  """ In-memory tree for easy traversal and lookup of images in a repository. """
+
+  def __init__(self, all_images, all_tags, base_filter=None):
+    self._tag_map = {}
+    self._image_map = {}
+
+    self._build(all_images, all_tags, base_filter)
+
+  def _build(self,  all_images, all_tags, base_filter=None):
+    # Build nodes for each of the images.
+    for image in all_images:
+      ancestors = image.ancestors.split('/')[1:-1]
+
+      # Filter any unneeded images.
+      if base_filter is not None:
+        if image.id != base_filter and not str(base_filter) in ancestors:
+          continue
+
+      self._image_map[image.id] = ImageTreeNode(image)
+
+    # Connect the nodes to their parents.
+    for image_node in self._image_map.values():
+      image = image_node.image
+      parent_image_id = image.ancestors.split('/')[-2] if image.ancestors else None
+      if not parent_image_id:
+        continue
+
+      parent_node = self._image_map.get(int(parent_image_id))
+      if parent_node is not None:
+        parent_node.add_child(image_node)
+
+    # Build the tag map.
+    for tag in all_tags:
+      image_node = self._image_map.get(tag.image.id)
+      if not image_node:
+        continue
+
+      self._tag_map = image_node
+      image_node.add_tag(tag.name)
+
+
+  def find_longest_path(self, image_id, checker):
+    """ Returns a list of images representing the longest path that matches the given
+        checker function, starting from the given image_id *exclusive*.
+    """
+    start_node = self._image_map.get(image_id)
+    if not start_node:
+      return []
+
+    return self._find_longest_path(start_node, checker, -1)[1:]
+
+
+  def _find_longest_path(self, image_node, checker, index):
+    found_path = []
+
+    for child_node in image_node.children:
+      if not checker(index + 1, child_node.image):
+        continue
+
+      found = self._find_longest_path(child_node, checker, index + 1)
+      if found and len(found) > len(found_path):
+        found_path = found
+
+    return [image_node.image] + found_path
+
+
+  def tag_containing_image(self, image):
+    """ Returns the name of the closest tag containing the given image. """
+    if not image:
+      return None
+
+    # Check the current image for a tag.
+    image_node = self._image_map.get(image.id)
+    if image_node is None:
+      return None
+
+    if image_node.tags:
+      return image_node.tags[0]
+
+    # Check any deriving images for a tag.
+    for child_node in image_node.children:
+      found = self.tag_containing_image(child_node.image)
+      if found is not None:
+        return found
+
+    return None
\ No newline at end of file