feat: integrate flagsmith client into API layer (#2447)

Co-authored-by: Kim Gustyr <kim.gustyr@flagsmith.com>

.github/workflows/update-flagsmith-environment.yml

@@ -0,0 +1,41 @@
+name: Update Flagsmith Defaults
+
+on:
+  schedule:
+    - cron: 0 8 * * *
+
+defaults:
+  run:
+    working-directory: api
+
+jobs:
+  update_server_defaults:
+    runs-on: ubuntu-latest
+    name: Update API Flagsmith Defaults
+    env:
+      FLAGSMITH_ON_FLAGSMITH_SERVER_API_URL: https://edge.api.flagsmith.com/api/v1
+      FLAGSMITH_ON_FLAGSMITH_SERVER_KEY: ${{ secrets.FLAGSMITH_ON_FLAGSMITH_SERVER_KEY }}
+
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Set up Python 3.11
+        uses: actions/setup-python@v4
+        with:
+          python-version: 3.11
+          cache: pip
+
+      - name: Install Dependencies
+        run: make install
+
+      - name: Update defaults
+        run: python manage.py updateflagsmithenvironment
+
+      - name: Create Pull Request
+        uses: peter-evans/create-pull-request@v5
+        with:
+          commit-message: Update API Flagsmith Defaults
+          branch: chore/update-api-flagsmith-environment
+          delete-branch: true
+          title: 'chore: update Flagsmith environment document'
+          labels: api

api/app/settings/common.py

@@ -148,6 +148,7 @@
     "integrations.slack",
     "integrations.webhook",
     "integrations.dynatrace",
+    "integrations.flagsmith",
     # Rate limiting admin endpoints
     "axes",
     "telemetry",
@@ -919,3 +920,13 @@
 
 # Limit the count of password reset emails that can be dispatched within the `PASSWORD_RESET_EMAIL_COOLDOWN` timeframe.
 MAX_PASSWORD_RESET_EMAILS = env.int("MAX_PASSWORD_RESET_EMAILS", 5)
+
+FLAGSMITH_ON_FLAGSMITH_SERVER_OFFLINE_MODE = env.bool(
+    "FLAGSMITH_ON_FLAGSMITH_SERVER_OFFLINE_MODE", default=True
+)
+FLAGSMITH_ON_FLAGSMITH_SERVER_KEY = env(
+    "FLAGSMITH_ON_FLAGSMITH_SERVER_KEY", default=None
+)
+FLAGSMITH_ON_FLAGSMITH_SERVER_API_URL = env(
+    "FLAGSMITH_ON_FLAGSMITH_SERVER_API_URL", default=FLAGSMITH_ON_FLAGSMITH_API_URL
+)

api/integrations/flagsmith/client.py

@@ -0,0 +1,54 @@
+"""
+Wrapper module for the flagsmith client to implement singleton behaviour and provide some
+additional logic by wrapping the client.
+
+Usage:
+
+```
+environment_flags = get_client().get_environment_flags()
+identity_flags = get_client().get_identity_flags()
+```
+
+Possible extensions:
+ - Allow for multiple clients?
+"""
+import typing
+
+from django.conf import settings
+from flagsmith import Flagsmith
+from flagsmith.offline_handlers import LocalFileHandler
+
+from integrations.flagsmith.exceptions import FlagsmithIntegrationError
+from integrations.flagsmith.flagsmith_service import ENVIRONMENT_JSON_PATH
+
+_flagsmith_client: typing.Optional[Flagsmith] = None
+
+
+def get_client() -> Flagsmith:
+    global _flagsmith_client
+
+    if not _flagsmith_client:
+        _flagsmith_client = Flagsmith(**_get_client_kwargs())
+
+    return _flagsmith_client
+
+
+def _get_client_kwargs() -> dict[str, typing.Any]:
+    _default_kwargs = {"offline_handler": LocalFileHandler(ENVIRONMENT_JSON_PATH)}
+
+    if settings.FLAGSMITH_ON_FLAGSMITH_SERVER_OFFLINE_MODE:
+        return {"offline_mode": True, **_default_kwargs}
+    elif (
+        settings.FLAGSMITH_ON_FLAGSMITH_SERVER_KEY
+        and settings.FLAGSMITH_ON_FLAGSMITH_SERVER_API_URL
+    ):
+        return {
+            "environment_key": settings.FLAGSMITH_ON_FLAGSMITH_SERVER_KEY,
+            "api_url": settings.FLAGSMITH_ON_FLAGSMITH_SERVER_API_URL,
+            **_default_kwargs,
+        }
+
+    raise FlagsmithIntegrationError(
+        "Must either use offline mode, or provide "
+        "FLAGSMITH_ON_FLAGSMITH_SERVER_KEY and FLAGSMITH_ON_FLAGSMITH_SERVER_API_URL."
+    )

api/integrations/flagsmith/data/environment.json

@@ -0,0 +1,34 @@
+{
+  "api_key": "masked",
+  "feature_states": [
+    {
+      "feature": {
+        "id": 51089,
+        "name": "test",
+        "type": "STANDARD"
+      },
+      "enabled": false,
+      "django_id": 286268,
+      "feature_segment": null,
+      "featurestate_uuid": "ec33a926-0b7e-4eb7-b02b-bf9df2ffa53e",
+      "feature_state_value": null,
+      "multivariate_feature_state_values": []
+    }
+  ],
+  "id": 0,
+  "name": "Development",
+  "project": {
+    "id": 0,
+    "name": "Flagsmith API",
+    "hide_disabled_flags": false,
+    "organisation": {
+      "id": 0,
+      "name": "Flagsmith",
+      "feature_analytics": false,
+      "stop_serving_flags": false,
+      "persist_trait_data": true
+    },
+    "segments": []
+  },
+  "use_identity_composite_key_for_hashing": true
+}

api/integrations/flagsmith/exceptions.py

@@ -0,0 +1,2 @@
+class FlagsmithIntegrationError(Exception):
+    pass

api/integrations/flagsmith/flagsmith_service.py

@@ -0,0 +1,75 @@
+import json
+import os
+
+import requests
+from django.conf import settings
+
+from integrations.flagsmith.exceptions import FlagsmithIntegrationError
+
+ENVIRONMENT_JSON_PATH = os.path.join(
+    os.path.dirname(os.path.realpath(__file__)), "data/environment.json"
+)
+
+KEEP_ENVIRONMENT_FIELDS = (
+    "name",
+    "feature_states",
+    "use_identity_composite_key_for_hashing",
+)
+KEEP_PROJECT_FIELDS = ("name", "organisation", "hide_disabled_flags")
+KEEP_ORGANISATION_FIELDS = (
+    "name",
+    "feature_analytics",
+    "stop_serving_flags",
+    "persist_trait_data",
+)
+
+
+def update_environment_json(environment_key: str = None, api_url: str = None) -> None:
+    environment_key = environment_key or settings.FLAGSMITH_ON_FLAGSMITH_SERVER_KEY
+    api_url = api_url or settings.FLAGSMITH_ON_FLAGSMITH_SERVER_API_URL
+
+    response = requests.get(
+        f"{api_url}/environment-document",
+        headers={"X-Environment-Key": environment_key},
+    )
+    if response.status_code != 200:
+        raise FlagsmithIntegrationError(
+            f"Couldn't get defaults from Flagsmith. Got {response.status_code} response."
+        )
+
+    environment_json = _get_masked_environment_data(response.json())
+    with open(ENVIRONMENT_JSON_PATH, "w+") as defaults:
+        defaults.write(json.dumps(environment_json, indent=2, sort_keys=True))
+
+
+def _get_masked_environment_data(environment_document: dict) -> dict:
+    """
+    Return a cut down / masked version of the environment
+    document which can be committed to VCS.
+    """
+
+    project_json = environment_document.pop("project")
+    organisation_json = project_json.pop("organisation")
+
+    return {
+        "id": 0,
+        "api_key": "masked",
+        **{
+            k: v
+            for k, v in environment_document.items()
+            if k in KEEP_ENVIRONMENT_FIELDS
+        },
+        "project": {
+            "id": 0,
+            **{k: v for k, v in project_json.items() if k in KEEP_PROJECT_FIELDS},
+            "organisation": {
+                "id": 0,
+                **{
+                    k: v
+                    for k, v in organisation_json.items()
+                    if k in KEEP_ORGANISATION_FIELDS
+                },
+            },
+            "segments": [],
+        },
+    }

api/integrations/flagsmith/management/commands/updateflagsmithenvironment.py

@@ -0,0 +1,8 @@
+from django.core.management import BaseCommand
+
+from integrations.flagsmith.flagsmith_service import update_environment_json
+
+
+class Command(BaseCommand):
+    def handle(self, *args, **options):
+        update_environment_json()

api/pyproject.toml

@@ -101,6 +101,7 @@ django-ses = "~3.5.0"
 django-axes = "~5.32.0"
 pydantic = "~1.10.9"
 pyngo = "~1.6.0"
+flagsmith = "^3.4.0"
 
 [tool.poetry.group.auth-controller.dependencies]
 django-multiselectfield = "~0.1.12"