From 1f3895315f1444959648d69599db3e8c49011554 Mon Sep 17 00:00:00 2001
From: David Moreau Simard <dmsimard@redhat.com>
Date: Sun, 2 Jun 2019 20:00:47 -0400
Subject: [PATCH] Make the API page size configurable

Instead of hard coding the page size to 100, make it configurable.

Change-Id: I399ff5a8d9f8fa6c61fcaabc6fafb0c30cc1dc55
---
 ara/server/settings.py           |  4 +++-
 doc/source/api-configuration.rst | 13 +++++++++++++
 roles/ara_api/defaults/main.yaml |  3 +++
 roles/ara_api/tasks/config.yaml  |  1 +
 4 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/ara/server/settings.py b/ara/server/settings.py
index b7a137e6..678bf318 100644
--- a/ara/server/settings.py
+++ b/ara/server/settings.py
@@ -187,9 +187,10 @@ WSGI_APPLICATION = "ara.server.wsgi.application"
 ROOT_URLCONF = "ara.server.urls"
 APPEND_SLASH = False
 
+PAGE_SIZE = settings.get("PAGE_SIZE", 100)
 REST_FRAMEWORK = {
     "DEFAULT_PAGINATION_CLASS": "rest_framework.pagination.LimitOffsetPagination",
-    "PAGE_SIZE": 100,
+    "PAGE_SIZE": PAGE_SIZE,
     "DEFAULT_FILTER_BACKENDS": ("django_filters.rest_framework.DjangoFilterBackend",),
     "DEFAULT_RENDERER_CLASSES": (
         "rest_framework.renderers.JSONRenderer",
@@ -232,6 +233,7 @@ if not os.path.exists(DEFAULT_SETTINGS) and "ARA_SETTINGS" not in os.environ:
         LOGGING=LOGGING,
         READ_LOGIN_REQUIRED=READ_LOGIN_REQUIRED,
         WRITE_LOGIN_REQUIRED=WRITE_LOGIN_REQUIRED,
+        PAGE_SIZE=PAGE_SIZE,
     )
     with open(DEFAULT_SETTINGS, "w+") as settings_file:
         comment = f"""
diff --git a/doc/source/api-configuration.rst b/doc/source/api-configuration.rst
index b74e0cfc..17faf244 100644
--- a/doc/source/api-configuration.rst
+++ b/doc/source/api-configuration.rst
@@ -48,6 +48,8 @@ For more details, click on the configuration parameters.
 +--------------------------------+--------------------------------------------------------+------------------------------------------------------+
 | ARA_LOG_LEVEL_                 | ``INFO``                                               | Log level of the different components                |
 +--------------------------------+--------------------------------------------------------+------------------------------------------------------+
+| ARA_PAGE_SIZE_                 | ``100``                                                | Amount of results returned per page by the API       |
++--------------------------------+--------------------------------------------------------+------------------------------------------------------+
 | ARA_READ_LOGIN_REQUIRED_       | ``False``                                              | Whether authentication is required for reading data  |
 +--------------------------------+--------------------------------------------------------+------------------------------------------------------+
 | ARA_SECRET_KEY_                | Randomized token, see ARA_SECRET_KEY_                  | Django's SECRET_KEY_ setting                         |
@@ -346,6 +348,17 @@ python library.
 
 .. _dynaconf: https://github.com/rochacbruno/dynaconf
 
+ARA_PAGE_SIZE
+~~~~~~~~~~~~~
+
+- **Environment variable**: ``ARA_PAGE_SIZE``
+- **Configuration file variable**: ``PAGE_SIZE``
+- **Type**: ``integer``
+- **Default**: ``50``
+- **Provided by**: django-rest-framework `pagination <https://www.django-rest-framework.org/api-guide/pagination/>`_
+
+When querying the API server, the amount of items per page returned.
+
 ARA_READ_LOGIN_REQUIRED
 ~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/roles/ara_api/defaults/main.yaml b/roles/ara_api/defaults/main.yaml
index 6d6945f6..e9aca0e6 100644
--- a/roles/ara_api/defaults/main.yaml
+++ b/roles/ara_api/defaults/main.yaml
@@ -96,6 +96,9 @@ ara_api_read_login_required: false
 # ARA_WRITE_LOGIN_REQUIRED - Whether authentication is required for writing data
 ara_api_write_login_required: false
 
+# ARA_PAGE_SIZE - Amount of results returned per page by the API
+ara_api_page_size: 100
+
 # ARA_LOG_LEVEL - Log level of the different components
 ara_api_log_level: INFO
 
diff --git a/roles/ara_api/tasks/config.yaml b/roles/ara_api/tasks/config.yaml
index 459b072c..4267d4bb 100644
--- a/roles/ara_api/tasks/config.yaml
+++ b/roles/ara_api/tasks/config.yaml
@@ -79,6 +79,7 @@
       SECRET_KEY: "{{ ara_api_secret_key }}"
       READ_LOGIN_REQUIRED: "{{ ara_api_read_login_required }}"
       WRITE_LOGIN_REQUIRED: "{{ ara_api_write_login_required }}"
+      PAGE_SIZE: "{{ ara_api_page_size }}"
   set_fact:
     ara_api_configuration: "{'{{ ara_api_env }}': {{ reconciled_configuration }} }"
   no_log: yes