chore(health): extract health into separate crate

libs/Cargo.toml

@@ -4,6 +4,7 @@ members = [
     "blockscout-auth",
     "blockscout-client/crate",
     "blockscout-db",
+    "endpoints/health",
     "blockscout-service-launcher",
     "display-bytes",
     "env-collector",

libs/endpoints/health/Cargo.toml

@@ -0,0 +1,14 @@
+[package]
+name = "blockscout-endpoint-health"
+version = "0.1.0"
+description = "Configuration tools for compiling health endpoint"
+license = "MIT"
+repository = "https://github.com/blockscout/blockscout-rs"
+keywords = ["blockscout", "service", "http", "microservices", "health", "endpoint"]
+categories = ["web-programming::http-server"]
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+prost-build = "0.11"

libs/endpoints/health/src/lib.rs

@@ -0,0 +1,49 @@
+//! Tools for setting up `/health` endpoint.
+//!
+//! ## Usage
+//! (example can be seen in `stats-proto` crate in this repo)
+//!
+//! 1. In `build.rs` in your crateuse [`add_to_compile_config`],
+//!     [`proto_files`], and [`includes`] for compiling `health.proto`
+//!     to rust code using [`prost_build`].
+//!
+//! 2. To include the generated code in your project, add the following to `lib.rs`
+//!     (`/grpc.health.v1.rs` is the file name chosen based on `package` in `.proto` file):
+//!     ```ignore
+//!     pub mod grpc {
+//!         pub mod health {
+//!             pub mod v1 {
+//!                 include!(concat!(env!("OUT_DIR"), "/grpc.health.v1.rs"));
+//!             }
+//!         }
+//!     }
+//!     ```
+//!
+//! 3. To enable swagger generation, add the following in `api_config_http.yaml`'s
+//!     http rules:
+//!     ```custom,{class=language-yaml}
+//!         - selector: grpc.health.v1.Health.Check
+//!           get: /health
+//!     ```
+//!
+//! Now the types should be available in `grpc::health::v1` module, and swagger
+//! entry for the endpoint should appear
+
+use std::path::{Path, PathBuf};
+
+use prost_build::Config;
+
+pub fn add_to_compile_config(config: &mut Config) {
+    config.bytes([".grpc.health"]).type_attribute(
+        ".grpc.health",
+        "#[actix_prost_macros::serde(rename_all=\"snake_case\")]",
+    );
+}
+
+pub fn proto_files(path_to_swagger_crate: &Path) -> Vec<PathBuf> {
+    vec![path_to_swagger_crate.join("proto/health.proto")]
+}
+
+pub fn includes(path_to_swagger_crate: &Path) -> Vec<PathBuf> {
+    vec![path_to_swagger_crate.join("proto")]
+}

stats/stats-proto/Cargo.toml

@@ -20,3 +20,4 @@ serde_json = "1.0"
 actix-prost-build = { git = "https://github.com/blockscout/actix-prost" }
 tonic-build = "0.8"
 prost-build = "0.11"
+blockscout-endpoint-health = { path = "../../libs/endpoints/health" }

stats/stats-proto/build.rs

@@ -1,6 +1,6 @@
 use actix_prost_build::{ActixGenerator, GeneratorList};
 use prost_build::{Config, ServiceGenerator};
-use std::path::Path;
+use std::path::{Path, PathBuf};
 
 // custom function to include custom generator
 fn compile(
@@ -16,33 +16,55 @@ fn compile(
         .protoc_arg("--openapiv2_opt")
         .protoc_arg("grpc_api_configuration=proto/api_config_http.yaml,output_format=yaml,allow_merge=true,merge_file_name=stats,json_names_for_fields=false")
         .bytes(["."])
-        .type_attribute(".", "#[actix_prost_macros::serde(rename_all=\"snake_case\")]")
+        .type_attribute(".blockscout.stats", "#[actix_prost_macros::serde(rename_all=\"snake_case\")]")
         .field_attribute(
             ".blockscout.stats.v1.HealthCheckRequest.service",
             "#[serde(default)]"
         )
         .field_attribute(".blockscout.stats.v1.Point.is_approximate", "#[serde(skip_serializing_if = \"std::ops::Not::not\")]")
         .field_attribute(".blockscout.stats.v1.Point.is_approximate", "#[serde(default)]")
         .field_attribute(".blockscout.stats.v1.GetLineChartRequest.resolution", "#[serde(default)]");
+    blockscout_endpoint_health::add_to_compile_config(&mut config);
 
     config.compile_protos(protos, includes)?;
     Ok(())
 }
 
+fn vec_path_buf_to_string(v: Vec<PathBuf>) -> Vec<String> {
+    v.into_iter()
+        .map(|path| {
+            path.to_str()
+                .expect("Non UTF-8 paths are not supported")
+                .to_string()
+        })
+        .collect()
+}
+
 fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let swagger_crate_folder = Path::new("../../libs/endpoints/health");
+
     // We need to rebuild proto lib only if any of proto definitions
     // (or corresponding http mapping) has been changed.
-    println!("cargo:rerun-if-changed=proto/");
+    let mut proto_files_folders = ["proto/"].map(PathBuf::from).to_vec();
+    proto_files_folders.extend(blockscout_endpoint_health::includes(swagger_crate_folder));
+    let proto_files_folders = vec_path_buf_to_string(proto_files_folders);
+
+    for folder in &proto_files_folders {
+        println!("cargo:rerun-if-changed={folder}/");
+    }
+
+    let mut protos = ["proto/stats.proto"].map(PathBuf::from).to_vec();
+    protos.extend(blockscout_endpoint_health::proto_files(
+        swagger_crate_folder,
+    ));
+    let protos = vec_path_buf_to_string(protos);
 
     std::fs::create_dir_all("./swagger").unwrap();
     let gens = Box::new(GeneratorList::new(vec![
         tonic_build::configure().service_generator(),
         Box::new(ActixGenerator::new("proto/api_config_http.yaml").unwrap()),
     ]));
-    compile(
-        &["proto/stats.proto", "proto/health.proto"],
-        &["proto"],
-        gens,
-    )?;
+
+    compile(&protos, &proto_files_folders, gens)?;
     Ok(())
 }

stats/stats-proto/proto/api_config_http.yaml

@@ -10,5 +10,5 @@ http:
     - selector: blockscout.stats.v1.StatsService.GetLineChart
       get: /api/v1/lines/{name}
 
-    - selector: blockscout.stats.v1.Health.Check
+    - selector: grpc.health.v1.Health.Check
       get: /health

stats/stats-proto/src/lib.rs

@@ -7,5 +7,13 @@ pub mod blockscout {
     }
 }
 
+pub mod grpc {
+    pub mod health {
+        pub mod v1 {
+            include!(concat!(env!("OUT_DIR"), "/grpc.health.v1.rs"));
+        }
+    }
+}
+
 #[cfg(test)]
 mod tests;

stats/stats-proto/swagger/stats.swagger.yaml

@@ -81,8 +81,15 @@ paths:
   /health:
     get:
       summary: |-
-        If the requested service is unknown, the call will fail with status
-        NOT_FOUND.
+        Check gets the health of the specified service. If the requested service
+        is unknown, the call will fail with status NOT_FOUND. If the caller does
+        not specify a service name, the server should respond with its overall
+        health status.
+      description: |-
+        Clients should set a deadline when calling Check, and can declare the
+        server unhealthy if they do not receive a timely response.
+
+        Check implementations should be idempotent and side effect free.
       operationId: Health_Check
       responses:
         "200":

stats/stats-server/src/health.rs

@@ -1,4 +1,4 @@
-use stats_proto::blockscout::stats::v1::{
+use stats_proto::grpc::health::v1::{
     health_check_response, health_server::Health, HealthCheckRequest, HealthCheckResponse,
 };
 

stats/stats-server/src/server.rs

@@ -11,11 +11,12 @@ use crate::{
 
 use blockscout_service_launcher::launcher::{self, LaunchSettings};
 use sea_orm::{ConnectOptions, Database};
-use stats_proto::blockscout::stats::v1::{
-    health_actix::route_health,
-    health_server::HealthServer,
-    stats_service_actix::route_stats_service,
-    stats_service_server::{StatsService, StatsServiceServer},
+use stats_proto::{
+    blockscout::stats::v1::{
+        stats_service_actix::route_stats_service,
+        stats_service_server::{StatsService, StatsServiceServer},
+    },
+    grpc::health::v1::{health_actix::route_health, health_server::HealthServer},
 };
 
 const SERVICE_NAME: &str = "stats";