📝(backend) add fulltext search documentation

Add documentation for env & Find+Docs configuration in dev mode

Signed-off-by: Fabre Florian <ffabre@hybird.org>

Author: joehybird

docs/architecture.md

@@ -12,6 +12,7 @@ flowchart TD
     Back --> DB("Database (PostgreSQL)")
     Back <--> Celery --> DB
     Back ----> S3("Minio (S3)")
+    Back -- REST API --> Find
 ```
 
 ### Architecture decision records

docs/env.md

@@ -93,6 +93,12 @@ These are the environment variables you can set for the `impress-backend` contai
 | OIDC_USERINFO_SHORTNAME_FIELD                   | OIDC token claims to create shortname                                                                                       | first_name                                                              |
 | POSTHOG_KEY                                     | Posthog key for analytics                                                                                                   |                                                                         |
 | REDIS_URL                                       | Cache url                                                                                                                   | redis://redis:6379/1                                                    |
+| SEARCH_INDEXER_CLASS                            | Class of the backend for document indexation & search                                                                       |                                                                         |
+| SEARCH_INDEXER_BATCH_SIZE                       | Size of each batch for indexation of all documents                                                                          | 100000                                                                  |
+| SEARCH_INDEXER_COUNTDOWN                        | Minimum debounce delay of indexation jobs (in seconds)                                                                      | 1                                                                       |
+| SEARCH_INDEXER_URL                              | Find application endpoint for indexation                                                                                    |                                                                         |
+| SEARCH_INDEXER_SECRET                           | Token for indexation queries                                                                                                |                                                                         |
+| SEARCH_INDEXER_QUERY_URL                        | Find application endpoint for search                                                                                        |                                                                         |
 | SENTRY_DSN                                      | Sentry host                                                                                                                 |                                                                         |
 | SESSION_COOKIE_AGE                              | duration of the cookie session                                                                                              | 60*60*12                                                                |
 | SPECTACULAR_SETTINGS_ENABLE_DJANGO_DEPLOY_CHECK |                                                                                                                             | false                                                                   |

docs/search.md

@@ -0,0 +1,39 @@
+# Setup the Find search for Impress
+
+This configuration will enable the fulltext search feature for Docs :
+- Each save on **core.Document** or **core.DocumentAccess** will trigger the indexer
+- The `api/v1.0/documents/search/` will work as a proxy with the Find API for fulltext search.
+
+## Create an index service for Docs
+
+Configure a **Service** for Docs application with these settings
+
+- **Name**: `docs`<br>_request.auth.name of the Docs application._
+- **Client id**: `impress`<br>_Name of the token audience or client_id of the Docs application._
+
+See [how-to-use-indexer.md](how-to-use-indexer.md) for details.
+
+## Configure settings of Docs
+
+Add those Django settings the Docs application to enable the feature.
+
+```shell
+SEARCH_INDEXER_CLASS="core.services.search_indexers.FindDocumentIndexer"
+SEARCH_INDEXER_COUNTDOWN=10  # Debounce delay in seconds for the indexer calls.
+
+# The token from service "docs" of Find application (development).
+SEARCH_INDEXER_SECRET="find-api-key-for-docs-with-exactly-50-chars-length"
+SEARCH_INDEXER_URL="http://find:8000/api/v1.0/documents/index/"
+
+# Search endpoint. Uses the OIDC token for authentication
+SEARCH_INDEXER_QUERY_URL="http://find:8000/api/v1.0/documents/search/"
+```
+
+We also need to enable the **OIDC Token** refresh or the authentication will fail quickly.
+
+```shell
+# Store OIDC tokens in the session
+OIDC_STORE_ACCESS_TOKEN = True  # Store the access token in the session
+OIDC_STORE_REFRESH_TOKEN = True  # Store the encrypted refresh token in the session
+OIDC_STORE_REFRESH_TOKEN_KEY = "your-32-byte-encryption-key=="  # Must be a valid Fernet key (32 url-safe base64-encoded bytes)
+```

docs/system-requirements.md

@@ -97,6 +97,17 @@ Production deployments differ significantly from development environments. The t
 | 5433      | PostgreSQL (Keycloak) |
 | 1081      | MailCatcher           |
 
+**With fulltext search service**
+
+| Port      | Service               |
+| --------- | --------------------- |
+| 8081      | Find (Django)         |
+| 9200      | Opensearch            |
+| 9600      | Opensearch admin      |
+| 5601      | Opensearch dashboard  |
+| 25432     | PostgreSQL (Find)     |
+
+
 ## 6. Sizing Guidelines
 
 **RAM** – start at 8 GB dev / 16 GB staging / 32 GB prod. Postgres and Keycloak are the first to OOM; scale them first.

env.d/development/common

@@ -36,6 +36,7 @@ OIDC_OP_JWKS_ENDPOINT=http://nginx:8083/realms/impress/protocol/openid-connect/c
 OIDC_OP_AUTHORIZATION_ENDPOINT=http://localhost:8083/realms/impress/protocol/openid-connect/auth
 OIDC_OP_TOKEN_ENDPOINT=http://nginx:8083/realms/impress/protocol/openid-connect/token
 OIDC_OP_USER_ENDPOINT=http://nginx:8083/realms/impress/protocol/openid-connect/userinfo
+OIDC_OP_INTROSPECTION_ENDPOINT=http://nginx:8083/realms/impress/protocol/openid-connect/token/introspect
 
 OIDC_RP_CLIENT_ID=impress
 OIDC_RP_CLIENT_SECRET=ThisIsAnExampleKeyForDevPurposeOnly