From f7f10f4a6df758e2887d0906c91fce405a33f97d Mon Sep 17 00:00:00 2001
From: Joseph Schorr <joseph.schorr@coreos.com>
Date: Tue, 30 Jun 2015 11:38:58 +0300
Subject: [PATCH] Add pagination support to tag history API

Fixes #198
---
 data/model/legacy.py |  4 ++--
 endpoints/api/tag.py | 21 +++++++++++++++++----
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/data/model/legacy.py b/data/model/legacy.py
index 721bb38bc..a41f4c36e 100644
--- a/data/model/legacy.py
+++ b/data/model/legacy.py
@@ -1861,14 +1861,14 @@ def _tag_alive(query, now_ts=None):
                      (RepositoryTag.lifetime_end_ts > now_ts))
 
 
-def list_repository_tag_history(repository, limit=100, specific_tag=None):
+def list_repository_tag_history(repository, page=1, size=100, specific_tag=None):
   query = (RepositoryTag
            .select(RepositoryTag, Image)
            .join(Image)
            .where(RepositoryTag.repository == repository)
            .where(RepositoryTag.hidden == False)
            .order_by(RepositoryTag.lifetime_start_ts.desc())
-           .limit(limit))
+           .paginate(page, size))
 
   if specific_tag:
     query = query.where(RepositoryTag.name == specific_tag)
diff --git a/endpoints/api/tag.py b/endpoints/api/tag.py
index 6e7c33a0a..4cdee1feb 100644
--- a/endpoints/api/tag.py
+++ b/endpoints/api/tag.py
@@ -16,12 +16,13 @@ from datetime import datetime
 @resource('/v1/repository/<repopath:repository>/tag/')
 @path_param('repository', 'The full path of the repository. e.g. namespace/name')
 class ListRepositoryTags(RepositoryParamResource):
-  """ Resource for listing repository tags. """
+  """ Resource for listing full repository tag history, alive *and dead*. """
 
   @require_repo_write
   @parse_args
   @query_param('specificTag', 'Filters the tags to the specific tag.', type=str, default='')
-  @query_param('limit', 'Limit to the number of results to return. Max 100.', type=int, default=50)
+  @query_param('limit', 'Limit to the number of results to return per page. Max 100.', type=int, default=50)
+  @query_param('page', 'Page index for the results. Default 1.', type=int, default=1)
   @nickname('listRepoTags')
   def get(self, args, namespace, repository):
     repo = model.get_repository(namespace, repository)
@@ -44,9 +45,21 @@ class ListRepositoryTags(RepositoryParamResource):
       return tag_info
 
     specific_tag = args.get('specificTag') or None
+
+    page = min(1, args.get('start', 1))
     limit = min(100, max(1, args.get('limit', 50)))
-    tags = model.list_repository_tag_history(repo, limit=limit, specific_tag=specific_tag)
-    return {'tags': [tag_view(tag) for tag in tags]}
+
+    # Note: We ask for limit+1 here, so we can check to see if there are
+    # additional pages of results.
+    tags = model.list_repository_tag_history(repo, page=page, size=limit+1,
+                                             specific_tag=specific_tag)
+
+    tags = list(tags)
+    return {
+      'tags': [tag_view(tag) for tag in tags[0:limit]],
+      'page': page,
+      'has_additional': len(tags) >= limit
+    }
 
 
 @resource('/v1/repository/<repopath:repository>/tag/<tag>')