Merge #4238

4238: Task queue webhook r=dureuill a=irevoire

# Prototype `prototype-task-queue-webhook-1`

The prototype is available through Docker by using the following command:

```bash
docker run -p 7700:7700 -v $(pwd)/meili_data:/meili_data getmeili/meilisearch:prototype-task-queue-webhook-1
```

# Pull Request

Implements the task queue webhook.

## Related issue
Fixes https://github.com/meilisearch/meilisearch/issues/4236

## What does this PR do?
- Provide a new cli and env var for the webhook, respectively called `--task-webhook-url` and `MEILI_TASK_WEBHOOK_URL`
- Also supports sending the requests with a custom `Authorization` header by specifying the optional `--task-webhook-authorization-header` CLI parameter or `MEILI_TASK_WEBHOOK_AUTHORIZATION_HEADER` env variable.
- Throw an error if the specified URL is invalid
- Every time a batch is processed, send all the finished tasks into the webhook with our public `TaskView` type as a JSON Line GZIPed body.
- Add one test.

## PR checklist

### Before becoming ready to review
- [x] Add a test
- [x] Compress the data we send
- [x] Chunk and stream the data we send
- [x] Remove the unwrap in the index-scheduler when sending the data fails
- [x] The analytics are missing

### Before merging
- [x] Release a prototype



Co-authored-by: Tamo <tamo@meilisearch.com>
Co-authored-by: Clément Renault <clement@meilisearch.com>

meilisearch/tests/tasks/mod.rs

@@ -1,4 +1,5 @@
 mod errors;
+mod webhook;
 
 use meili_snap::insta::assert_json_snapshot;
 use time::format_description::well_known::Rfc3339;

meilisearch/tests/tasks/webhook.rs

@@ -0,0 +1,123 @@
+//! To test the webhook, we need to spawn a new server with a URL listening for
+//! post requests. The webhook handle starts a server and forwards all the
+//! received requests into a channel for you to handle.
+
+use std::sync::Arc;
+
+use actix_http::body::MessageBody;
+use actix_web::dev::{ServiceFactory, ServiceResponse};
+use actix_web::web::{Bytes, Data};
+use actix_web::{post, App, HttpResponse, HttpServer};
+use meili_snap::{json_string, snapshot};
+use meilisearch::Opt;
+use tokio::sync::mpsc;
+use url::Url;
+
+use crate::common::{default_settings, Server};
+use crate::json;
+
+#[post("/")]
+async fn forward_body(sender: Data<mpsc::UnboundedSender<Vec<u8>>>, body: Bytes) -> HttpResponse {
+    let body = body.to_vec();
+    sender.send(body).unwrap();
+    HttpResponse::Ok().into()
+}
+
+fn create_app(
+    sender: Arc<mpsc::UnboundedSender<Vec<u8>>>,
+) -> actix_web::App<
+    impl ServiceFactory<
+        actix_web::dev::ServiceRequest,
+        Config = (),
+        Response = ServiceResponse<impl MessageBody>,
+        Error = actix_web::Error,
+        InitError = (),
+    >,
+> {
+    App::new().service(forward_body).app_data(Data::from(sender))
+}
+
+struct WebhookHandle {
+    pub server_handle: tokio::task::JoinHandle<Result<(), std::io::Error>>,
+    pub url: String,
+    pub receiver: mpsc::UnboundedReceiver<Vec<u8>>,
+}
+
+async fn create_webhook_server() -> WebhookHandle {
+    let mut log_builder = env_logger::Builder::new();
+    log_builder.parse_filters("info");
+    log_builder.init();
+
+    let (sender, receiver) = mpsc::unbounded_channel();
+    let sender = Arc::new(sender);
+
+    // By listening on the port 0, the system will give us any available port.
+    let server =
+        HttpServer::new(move || create_app(sender.clone())).bind(("127.0.0.1", 0)).unwrap();
+    let (ip, scheme) = server.addrs_with_scheme()[0];
+    let url = format!("{scheme}://{ip}/");
+
+    let server_handle = tokio::spawn(server.run());
+    WebhookHandle { server_handle, url, receiver }
+}
+
+#[actix_web::test]
+async fn test_basic_webhook() {
+    let WebhookHandle { server_handle, url, mut receiver } = create_webhook_server().await;
+
+    let db_path = tempfile::tempdir().unwrap();
+    let server = Server::new_with_options(Opt {
+        task_webhook_url: Some(Url::parse(&url).unwrap()),
+        ..default_settings(db_path.path())
+    })
+    .await
+    .unwrap();
+
+    let index = server.index("tamo");
+    // May be flaky: we're relying on the fact that while the first document addition is processed, the other
+    // operations will be received and will be batched together. If it doesn't happen it's not a problem
+    // the rest of the test won't assume anything about the number of tasks per batch.
+    for i in 0..5 {
+        let (_, _status) = index.add_documents(json!({ "id": i, "doggo": "bone" }), None).await;
+    }
+
+    let mut nb_tasks = 0;
+    while let Some(payload) = receiver.recv().await {
+        let payload = String::from_utf8(payload).unwrap();
+        let jsonl = payload.split('\n');
+        for json in jsonl {
+            if json.is_empty() {
+                break; // we reached EOF
+            }
+            nb_tasks += 1;
+            let json: serde_json::Value = serde_json::from_str(json).unwrap();
+            snapshot!(
+                json_string!(json, { ".uid" => "[uid]", ".duration" => "[duration]", ".enqueuedAt" => "[date]", ".startedAt" => "[date]", ".finishedAt" => "[date]" }),
+            @r###"
+            {
+              "uid": "[uid]",
+              "indexUid": "tamo",
+              "status": "succeeded",
+              "type": "documentAdditionOrUpdate",
+              "canceledBy": null,
+              "details": {
+                "receivedDocuments": 1,
+                "indexedDocuments": 1
+              },
+              "error": null,
+              "duration": "[duration]",
+              "enqueuedAt": "[date]",
+              "startedAt": "[date]",
+              "finishedAt": "[date]"
+            }
+            "###);
+        }
+        if nb_tasks == 5 {
+            break;
+        }
+    }
+
+    assert!(nb_tasks == 5, "We should have received the 5 tasks but only received {nb_tasks}");
+
+    server_handle.abort();
+}