Create indexer service framework

[Jannis]

This introduces a framework for writing any type of HTTP-based indexer service using a skeleton like the one below. A working implementation for one of the upcoming data services already exists, my next goal is to port the existing subgraph indexer-service in this repository to this framework as well. But that will happen in a separate PR.

#[async_trait]
impl IndexerServiceImpl for MyService {
    type Error = MyServiceError;
    type Request = MyServiceRequest;
    type Response = MyServiceResponse;
    type State = MyServiceState;

    async fn process_request(
        &self,
        manifest_id: DeploymentId,
        request: Self::Request,
    ) -> Result<(Self::Request, Self::Response), Self::Error> {
        Ok((request, MyServiceResponse::new("some response", true)))
    }
}

#[tokio::main]
async fn main() -> Result<(), Error> {
    // Like any indexer service, we need to expose a cost and a status API; in
    // line with what the subgraph indexer service does, we're using two GraphQL
    // schemas for these
    let cost_schema = routes::cost::build_schema().await;
    let status_schema = routes::status::build_schema().await;

    // Some of the service configuration goes into the so-called
    // "state", which will be passed to any request handler, middleware etc.
    // that is involved in serving requests
    let state = Arc::new(MyServiceState {
        cost_schema,
        status_schema,
        config: config.clone(),
    });

    // Run the service
    IndexerService::run(IndexerServiceOptions {
        release,
        config: config.common.clone(),
        url_namespace: "myservice",
        metrics_prefix: "myservice",
        service_impl: MyService::new(config),
        extra_routes: Router::new()
            .route("/cost", post(routes::cost::cost))
            .route("/status", post(routes::status::status))
            .route("/myservice/health/:id", get(routes::health::health))
            .with_state(state),
    })
    .await
}

[github-actions]

Pull Request Test Coverage Report for Build 6660418515

• 0 of 302 (0.0%) changed or added relevant lines in 6 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-4.4%) to 45.885%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
service/src/server/mod.rs	0	1	0.0%
service/src/main.rs	0	2	0.0%
common/src/indexer_service/http/config.rs	0	8	0.0%
common/src/indexer_service/http/scalar_receipt_header.rs	0	30	0.0%
common/src/indexer_service/http/request_handler.rs	0	65	0.0%
common/src/indexer_service/http/indexer_service.rs	0	196	0.0%

Totals
Change from base Build 6644835579:	-4.4%
Covered Lines:	1394
Relevant Lines:	3038

---

💛 - Coveralls

[github-actions]

Pull Request Test Coverage Report for Build 7066306592

• 64 of 332 (19.28%) changed or added relevant lines in 8 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-2.8%) to 56.332%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
common/src/test_vectors.rs	19	20	95.0%
service/src/server/mod.rs	0	1	0.0%
service/src/main.rs	0	2	0.0%
common/src/indexer_service/http/config.rs	0	8	0.0%
common/src/indexer_service/http/request_handler.rs	0	12	0.0%
common/src/indexer_service/http/scalar_receipt_header.rs	45	60	75.0%
common/src/indexer_service/http/metrics.rs	0	24	0.0%
common/src/indexer_service/http/indexer_service.rs	0	205	0.0%

Totals
Change from base Build 7066070746:	-2.8%
Covered Lines:	2442
Relevant Lines:	4335

---

💛 - Coveralls

[hopeyen]

very 🧠 !

[Jannis]

@hopeyen Addressed your comments so far!

[hopeyen]

@hopeyen Addressed your comments so far!

Thanks! Is it cool if I wait for #104 to be ready to review together?

[Jannis]

@hopeyen Addressed your comments so far!

Thanks! Is it cool if I wait for #104 to be ready to review together?

@hopeyen I'd prefer to merge this one before just to not leave so many changes hanging in the air. But I could go either way.

[aasseman]

Very clean! LGTM!

[aasseman]

Very clean! LGTM!