feat: [Improvement] Adds FORUM_ENV filter to manage forum environment vars

README.rst

@@ -34,6 +34,31 @@ Configuration
 - ``FORUM_REPOSITORY`` (default: ``"https://github.com/openedx/cs_comments_service.git"``)
 - ``FORUM_REPOSITORY_VERSION`` (default: ``"{{ OPENEDX_COMMON_VERSION }}"``)
 
+Customising Environment Variables
+---------------------------------
+
+To add, or modify environment variables that are supplied to the forum service,
+you can use the ``FORUM_ENV`` hook.
+
+To add or modify a environment variable, update the corresponding entry in the
+``FORUM_ENV`` dict as follows:
+
+.. code-block:: python
+
+    from tutorforum.hooks import FORUM_ENV
+
+    @FORUM_ENV.add()
+    def _add_forum_env_vars(env_vars):
+        env_vars.update({ "NEW_ENV_VAR": "VALUE" })
+        return env_vars
+
+If the environment variable already exists, it will be overridden, otherwise it
+will be added. Note that if multiple plugins override the same value, the last
+override will apply.
+
+It is posible to use templates when setting the above values.
+
+
 Caveats for the `mongodb+srv://` syntax
 ---------------------------------------
 

changelog.d/20230731_182614_kshitij_forum_environment_plugin.md

@@ -0,0 +1,6 @@
+- [Improvement] Introduces the `FORUM_ENV` filter to which any additional forum
+  which simplifies management of environment variables for the forum service. 
+  Additional environment variables can be added to this filter, and existing
+  values can be removed as needed by plugins. These are rendered into the new 
+  `forum-k8s-env` and `forum-local-env` patches for the kubernetes and docker
+  configs respectively. (by @xitij2000)

tutorforum/hooks.py

@@ -0,0 +1,11 @@
+"""
+These hooks are stored in a separate module. If they were included in plugin.py, then
+the tutor-forum hooks would be created in the context of some other plugin that imports
+them.
+"""
+from __future__ import annotations
+
+from tutor.core.hooks import Filter
+
+
+FORUM_ENV: Filter[dict[str, str], []] = Filter()

tutorforum/patches/k8s-deployments

@@ -23,20 +23,4 @@ spec:
           ports:
             - containerPort: {{ FORUM_PORT }}
           env:
-            - name: SEARCH_SERVER
-              value: "{{ ELASTICSEARCH_SCHEME }}://{{ ELASTICSEARCH_HOST }}:{{ ELASTICSEARCH_PORT }}"
-            - name: MONGODB_AUTH
-              value: "{% if MONGODB_USERNAME and MONGODB_PASSWORD %}{{ MONGODB_USERNAME}}:{{ MONGODB_PASSWORD }}@{% endif %}"
-            - name: MONGODB_HOST
-              value: "{{ MONGODB_HOST|forum_mongodb_host }}"
-            - name: MONGODB_PORT
-              value: "{{ MONGODB_PORT }}"
-            - name: MONGODB_DATABASE
-              value: "{{ FORUM_MONGODB_DATABASE }}"
-            - name: MONGOID_USE_SSL
-              value: "{{ 'true' if MONGODB_USE_SSL else 'false' }}"
-            - name: MONGOID_AUTH_SOURCE
-              value: "{{MONGODB_AUTH_SOURCE}}"
-            - name: MONGOID_AUTH_MECH
-              value: "{{ MONGODB_AUTH_MECHANISM|auth_mech_as_ruby }}"
-
+            {{ patch("forum-k8s-env")|indent(12) }}

tutorforum/patches/k8s-jobs

@@ -13,19 +13,4 @@ spec:
       - name: forum
         image: {{ FORUM_DOCKER_IMAGE }}
         env:
-          - name: SEARCH_SERVER
-            value: "{{ ELASTICSEARCH_SCHEME }}://{{ ELASTICSEARCH_HOST }}:{{ ELASTICSEARCH_PORT }}"
-          - name: MONGODB_AUTH
-            value: "{% if MONGODB_USERNAME and MONGODB_PASSWORD %}{{ MONGODB_USERNAME}}:{{ MONGODB_PASSWORD }}@{% endif %}"
-          - name: MONGODB_HOST
-            value: "{{ MONGODB_HOST|forum_mongodb_host }}"
-          - name: MONGODB_PORT
-            value: "{{ MONGODB_PORT }}"
-          - name: MONGODB_DATABASE
-            value: "{{ FORUM_MONGODB_DATABASE }}"
-          - name: MONGOID_USE_SSL
-            value: "{{ 'true' if MONGODB_USE_SSL else 'false' }}"
-          - name: MONGOID_AUTH_SOURCE
-            value: "{{MONGODB_AUTH_SOURCE}}"
-          - name: MONGOID_AUTH_MECH
-            value: "{{ MONGODB_AUTH_MECHANISM|auth_mech_as_ruby }}"
+          {{ patch("forum-k8s-env")|indent(10) }}

tutorforum/patches/local-docker-compose-jobs-services

@@ -1,12 +1,5 @@
 forum-job:
   image: {{ FORUM_DOCKER_IMAGE }}
   environment:
-    SEARCH_SERVER: "{{ ELASTICSEARCH_SCHEME }}://{{ ELASTICSEARCH_HOST }}:{{ ELASTICSEARCH_PORT }}"
-    MONGODB_AUTH: "{% if MONGODB_USERNAME and MONGODB_PASSWORD %}{{ MONGODB_USERNAME}}:{{ MONGODB_PASSWORD }}@{% endif %}"
-    MONGODB_HOST: "{{ MONGODB_HOST|forum_mongodb_host }}"
-    MONGODB_PORT: "{{ MONGODB_PORT }}"
-    MONGODB_DATABASE: "{{ FORUM_MONGODB_DATABASE }}"
-    MONGOID_AUTH_SOURCE: "{{ MONGODB_AUTH_SOURCE }}"
-    MONGOID_AUTH_MECH: "{{ MONGODB_AUTH_MECHANISM|auth_mech_as_ruby }}"
-    MONGOID_USE_SSL: "{{ 'true' if MONGODB_USE_SSL else 'false' }}"
+    {{ patch("forum-local-env")|indent(4) }}
   depends_on: {{ [("elasticsearch", RUN_ELASTICSEARCH), ("mongodb", RUN_MONGODB)]|list_if }}

tutorforum/patches/local-docker-compose-services

@@ -1,13 +1,6 @@
 forum:
   image: {{ FORUM_DOCKER_IMAGE }}
   environment:
-    SEARCH_SERVER: "{{ ELASTICSEARCH_SCHEME }}://{{ ELASTICSEARCH_HOST }}:{{ ELASTICSEARCH_PORT }}"
-    MONGODB_AUTH: "{% if MONGODB_USERNAME and MONGODB_PASSWORD %}{{ MONGODB_USERNAME}}:{{ MONGODB_PASSWORD }}@{% endif %}"
-    MONGODB_HOST: "{{ MONGODB_HOST|forum_mongodb_host }}"
-    MONGODB_PORT: "{{ MONGODB_PORT }}"
-    MONGODB_DATABASE: "{{ FORUM_MONGODB_DATABASE }}"
-    MONGOID_AUTH_SOURCE: "{{ MONGODB_AUTH_SOURCE }}"
-    MONGOID_AUTH_MECH: "{{ MONGODB_AUTH_MECHANISM|auth_mech_as_ruby }}"
-    MONGOID_USE_SSL: "{{ 'true' if MONGODB_USE_SSL else 'false' }}"
+    {{ patch("forum-local-env")|indent(4) }}
   restart: unless-stopped
   depends_on: {{ [("elasticsearch", RUN_ELASTICSEARCH), ("mongodb", RUN_MONGODB)]|list_if }}

tutorforum/plugin.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 from glob import glob
 import os
 import urllib.parse
@@ -7,7 +9,7 @@
 from tutor import hooks as tutor_hooks
 
 from .__about__ import __version__
-
+from .hooks import FORUM_ENV
 
 config = {
     "defaults": {
@@ -21,6 +23,18 @@
     },
 }
 
+FORUM_ENV_BASE: dict[str,str] = {
+    "SEARCH_SERVER": "{{ ELASTICSEARCH_SCHEME }}://{{ ELASTICSEARCH_HOST }}:{{ ELASTICSEARCH_PORT }}",
+    "MONGODB_AUTH":
+     "{% if MONGODB_USERNAME and MONGODB_PASSWORD %}{{ MONGODB_USERNAME}}:{{ MONGODB_PASSWORD }}@{% endif %}",
+    "MONGODB_HOST": "{{ MONGODB_HOST|forum_mongodb_host }}",
+    "MONGODB_PORT": "{{ MONGODB_PORT }}",
+    "MONGODB_DATABASE": "{{ FORUM_MONGODB_DATABASE }}",
+    "MONGOID_AUTH_SOURCE": "{{ MONGODB_AUTH_SOURCE }}",
+    "MONGOID_AUTH_MECH": "{{ MONGODB_AUTH_MECHANISM|auth_mech_as_ruby }}",
+    "MONGOID_USE_SSL": "{{ 'true' if MONGODB_USE_SSL else 'false' }}",
+}
+
 with open(
     pkg_resources.resource_filename(
         "tutorforum", os.path.join("templates", "forum", "tasks", "forum", "init")
@@ -112,6 +126,35 @@ def forum_mongodb_host(host: str) -> str:
     return urllib.parse.urlunparse(parsed)
 
 
+@FORUM_ENV.add(priority=tutor_hooks.priorities.HIGH)
+def _add_base_forum_env(forum_env: dict) -> dict[str, str]:
+    """
+    Add environment variables needed for standard build of forum service.
+    """
+    forum_env.update(FORUM_ENV_BASE)
+    return forum_env
+
+
+@tutor_hooks.Filters.ENV_PATCHES.add(priority=tutor_hooks.priorities.HIGH)
+def _forum_env_patches(patches):
+    """
+    Adds environment variables from FORUM_ENV filter to patches.
+    """
+    # The forum service is configured entirely via environment variables. Docker
+    # Compose and Kubernetes use different syntax to specify environement
+    # variables. The following code reads environemnt variables from the
+    # `FORUM_ENV` filter and rendered in the appropriate format for both so they
+    # can be included as patches.
+    k8s_env_patch = ""
+    local_env_patch = ""
+    for key, value in FORUM_ENV.apply({}).items():
+        # Kubernetes
+        k8s_env_patch += f'- name: {key}\n  value: "{value}"\n'
+        local_env_patch += f'{key}: "{value}"\n'
+    patches += [("forum-k8s-env", k8s_env_patch), ("forum-local-env", local_env_patch)]
+    return patches
+
+
 tutor_hooks.Filters.ENV_TEMPLATE_FILTERS.add_items(
     [
         ("auth_mech_as_ruby", auth_mech_as_ruby),