feat: Added grpc based health check (#6441)

Co-authored-by: hyperswitch-bot[bot] <148525504+hyperswitch-bot[bot]@users.noreply.github.com>

config/config.example.toml

@@ -790,3 +790,4 @@ connector_list = "cybersource" # Supported connectors for network tokenization
 [grpc_client.dynamic_routing_client] # Dynamic Routing Client Configuration
 host = "localhost" # Client Host
 port = 7000        # Client Port
+service = "dynamo" # Service name

config/deployments/env_specific.toml

@@ -326,3 +326,4 @@ check_token_status_url= ""    # base url to check token status from token servic
 [grpc_client.dynamic_routing_client] # Dynamic Routing Client Configuration
 host = "localhost" # Client Host
 port = 7000        # Client Port
+service = "dynamo" # Service name

crates/api_models/Cargo.toml

@@ -20,6 +20,7 @@ v1 = ["common_utils/v1"]
 v2 = ["common_utils/v2", "customer_v2"]
 customer_v2 = ["common_utils/customer_v2"]
 payment_methods_v2 = ["common_utils/payment_methods_v2"]
+dynamic_routing = []
 
 [dependencies]
 actix-web = { version = "4.5.1", optional = true }

crates/api_models/src/health_check.rs

@@ -1,3 +1,4 @@
+use std::collections::hash_map::HashMap;
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 pub struct RouterHealthCheckResponse {
     pub database: bool,
@@ -9,10 +10,22 @@ pub struct RouterHealthCheckResponse {
     #[cfg(feature = "olap")]
     pub opensearch: bool,
     pub outgoing_request: bool,
+    #[cfg(feature = "dynamic_routing")]
+    pub grpc_health_check: HealthCheckMap,
 }
 
 impl common_utils::events::ApiEventMetric for RouterHealthCheckResponse {}
 
+/// gRPC based services eligible for Health check
+#[derive(Debug, Clone, Eq, PartialEq, Hash, serde::Serialize, serde::Deserialize)]
+#[serde(rename_all = "snake_case")]
+pub enum HealthCheckServices {
+    /// Dynamic routing service
+    DynamicRoutingService,
+}
+
+pub type HealthCheckMap = HashMap<HealthCheckServices, bool>;
+
 #[derive(Debug, Clone, serde::Serialize, serde::Deserialize)]
 pub struct SchedulerHealthCheckResponse {
     pub database: bool,

crates/external_services/build.rs

@@ -3,11 +3,21 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     #[cfg(feature = "dynamic_routing")]
     {
         // Get the directory of the current crate
-        let proto_file = router_env::workspace_path()
-            .join("proto")
-            .join("success_rate.proto");
+
+        let proto_path = router_env::workspace_path().join("proto");
+        let success_rate_proto_file = proto_path.join("success_rate.proto");
+
+        let health_check_proto_file = proto_path.join("health_check.proto");
+        let out_dir = std::path::PathBuf::from(std::env::var("OUT_DIR")?);
+
         // Compile the .proto file
-        tonic_build::compile_protos(proto_file).expect("Failed to compile success rate proto file");
+        tonic_build::configure()
+            .out_dir(out_dir)
+            .compile(
+                &[success_rate_proto_file, health_check_proto_file],
+                &[proto_path],
+            )
+            .expect("Failed to compile proto files");
     }
     Ok(())
 }

crates/external_services/src/grpc_client.rs

@@ -1,11 +1,28 @@
 /// Dyanimc Routing Client interface implementation
 #[cfg(feature = "dynamic_routing")]
 pub mod dynamic_routing;
+/// gRPC based Heath Check Client interface implementation
+#[cfg(feature = "dynamic_routing")]
+pub mod health_check_client;
 use std::{fmt::Debug, sync::Arc};
 
 #[cfg(feature = "dynamic_routing")]
 use dynamic_routing::{DynamicRoutingClientConfig, RoutingStrategy};
+#[cfg(feature = "dynamic_routing")]
+use health_check_client::HealthCheckClient;
+#[cfg(feature = "dynamic_routing")]
+use http_body_util::combinators::UnsyncBoxBody;
+#[cfg(feature = "dynamic_routing")]
+use hyper::body::Bytes;
+#[cfg(feature = "dynamic_routing")]
+use hyper_util::client::legacy::connect::HttpConnector;
 use serde;
+#[cfg(feature = "dynamic_routing")]
+use tonic::Status;
+
+#[cfg(feature = "dynamic_routing")]
+/// Hyper based Client type for maintaining connection pool for all gRPC services
+pub type Client = hyper_util::client::legacy::Client<HttpConnector, UnsyncBoxBody<Bytes, Status>>;
 
 /// Struct contains all the gRPC Clients
 #[derive(Debug, Clone)]
@@ -13,6 +30,9 @@ pub struct GrpcClients {
     /// The routing client
     #[cfg(feature = "dynamic_routing")]
     pub dynamic_routing: RoutingStrategy,
+    /// Health Check client for all gRPC services
+    #[cfg(feature = "dynamic_routing")]
+    pub health_client: HealthCheckClient,
 }
 /// Type that contains the configs required to construct a  gRPC client with its respective services.
 #[derive(Debug, Clone, serde::Deserialize, serde::Serialize, Default)]
@@ -29,17 +49,30 @@ impl GrpcClientSettings {
     /// This function will be called at service startup.
     #[allow(clippy::expect_used)]
     pub async fn get_grpc_client_interface(&self) -> Arc<GrpcClients> {
+        #[cfg(feature = "dynamic_routing")]
+        let client =
+            hyper_util::client::legacy::Client::builder(hyper_util::rt::TokioExecutor::new())
+                .http2_only(true)
+                .build_http();
+
         #[cfg(feature = "dynamic_routing")]
         let dynamic_routing_connection = self
             .dynamic_routing_client
             .clone()
-            .get_dynamic_routing_connection()
+            .get_dynamic_routing_connection(client.clone())
             .await
             .expect("Failed to establish a connection with the Dynamic Routing Server");
 
+        #[cfg(feature = "dynamic_routing")]
+        let health_client = HealthCheckClient::build_connections(self, client)
+            .await
+            .expect("Failed to build gRPC connections");
+
         Arc::new(GrpcClients {
             #[cfg(feature = "dynamic_routing")]
             dynamic_routing: dynamic_routing_connection,
+            #[cfg(feature = "dynamic_routing")]
+            health_client,
         })
     }
 }

crates/external_services/src/grpc_client/dynamic_routing.rs

@@ -6,9 +6,6 @@ use api_models::routing::{
 };
 use common_utils::{errors::CustomResult, ext_traits::OptionExt, transformers::ForeignTryFrom};
 use error_stack::ResultExt;
-use http_body_util::combinators::UnsyncBoxBody;
-use hyper::body::Bytes;
-use hyper_util::client::legacy::connect::HttpConnector;
 use router_env::logger;
 use serde;
 use success_rate::{
@@ -18,7 +15,8 @@ use success_rate::{
     InvalidateWindowsResponse, LabelWithStatus, UpdateSuccessRateWindowConfig,
     UpdateSuccessRateWindowRequest, UpdateSuccessRateWindowResponse,
 };
-use tonic::Status;
+
+use super::Client;
 #[allow(
     missing_docs,
     unused_qualifications,
@@ -45,8 +43,6 @@ pub enum DynamicRoutingError {
     SuccessRateBasedRoutingFailure(String),
 }
 
-type Client = hyper_util::client::legacy::Client<HttpConnector, UnsyncBoxBody<Bytes, Status>>;
-
 /// Type that consists of all the services provided by the client
 #[derive(Debug, Clone)]
 pub struct RoutingStrategy {
@@ -64,6 +60,8 @@ pub enum DynamicRoutingClientConfig {
         host: String,
         /// The port of the client
         port: u16,
+        /// Service name
+        service: String,
     },
     #[default]
     /// If the dynamic routing client config has been disabled
@@ -74,13 +72,10 @@ impl DynamicRoutingClientConfig {
     /// establish connection with the server
     pub async fn get_dynamic_routing_connection(
         self,
+        client: Client,
     ) -> Result<RoutingStrategy, Box<dyn std::error::Error>> {
-        let client =
-            hyper_util::client::legacy::Client::builder(hyper_util::rt::TokioExecutor::new())
-                .http2_only(true)
-                .build_http();
         let success_rate_client = match self {
-            Self::Enabled { host, port } => {
+            Self::Enabled { host, port, .. } => {
                 let uri = format!("http://{}:{}", host, port).parse::<tonic::transport::Uri>()?;
                 logger::info!("Connection established with dynamic routing gRPC Server");
                 Some(SuccessRateCalculatorClient::with_origin(client, uri))

crates/external_services/src/grpc_client/health_check_client.rs

@@ -0,0 +1,149 @@
+use std::{collections::HashMap, fmt::Debug};
+
+use api_models::health_check::{HealthCheckMap, HealthCheckServices};
+use common_utils::{errors::CustomResult, ext_traits::AsyncExt};
+use error_stack::ResultExt;
+pub use health_check::{
+    health_check_response::ServingStatus, health_client::HealthClient, HealthCheckRequest,
+    HealthCheckResponse,
+};
+use router_env::logger;
+
+#[allow(
+    missing_docs,
+    unused_qualifications,
+    clippy::unwrap_used,
+    clippy::as_conversions,
+    clippy::use_self
+)]
+pub mod health_check {
+    tonic::include_proto!("grpc.health.v1");
+}
+
+use super::{Client, DynamicRoutingClientConfig, GrpcClientSettings};
+
+/// Result type for Dynamic Routing
+pub type HealthCheckResult<T> = CustomResult<T, HealthCheckError>;
+/// Dynamic Routing Errors
+#[derive(Debug, Clone, thiserror::Error)]
+pub enum HealthCheckError {
+    /// The required input is missing
+    #[error("Missing fields: {0} for building the Health check connection")]
+    MissingFields(String),
+    /// Error from gRPC Server
+    #[error("Error from gRPC Server : {0}")]
+    ConnectionError(String),
+    /// status is invalid
+    #[error("Invalid Status from server")]
+    InvalidStatus,
+}
+
+/// Health Check Client type
+#[derive(Debug, Clone)]
+pub struct HealthCheckClient {
+    /// Health clients for all gRPC based services
+    pub clients: HashMap<HealthCheckServices, HealthClient<Client>>,
+}
+
+impl HealthCheckClient {
+    /// Build connections to all gRPC services
+    pub async fn build_connections(
+        config: &GrpcClientSettings,
+        client: Client,
+    ) -> Result<Self, Box<dyn std::error::Error>> {
+        let dynamic_routing_config = &config.dynamic_routing_client;
+        let connection = match dynamic_routing_config {
+            DynamicRoutingClientConfig::Enabled {
+                host,
+                port,
+                service,
+            } => Some((host.clone(), *port, service.clone())),
+            _ => None,
+        };
+
+        let mut client_map = HashMap::new();
+
+        if let Some(conn) = connection {
+            let uri = format!("http://{}:{}", conn.0, conn.1).parse::<tonic::transport::Uri>()?;
+            let health_client = HealthClient::with_origin(client, uri);
+
+            client_map.insert(HealthCheckServices::DynamicRoutingService, health_client);
+        }
+
+        Ok(Self {
+            clients: client_map,
+        })
+    }
+    /// Perform health check for all services involved
+    pub async fn perform_health_check(
+        &self,
+        config: &GrpcClientSettings,
+    ) -> HealthCheckResult<HealthCheckMap> {
+        let dynamic_routing_config = &config.dynamic_routing_client;
+        let connection = match dynamic_routing_config {
+            DynamicRoutingClientConfig::Enabled {
+                host,
+                port,
+                service,
+            } => Some((host.clone(), *port, service.clone())),
+            _ => None,
+        };
+
+        let health_client = self
+            .clients
+            .get(&HealthCheckServices::DynamicRoutingService);
+
+        // SAFETY : This is a safe cast as there exists a valid
+        // integer value for this variant
+        #[allow(clippy::as_conversions)]
+        let expected_status = ServingStatus::Serving as i32;
+
+        let mut service_map = HealthCheckMap::new();
+
+        let health_check_succeed = connection
+            .as_ref()
+            .async_map(|conn| self.get_response_from_grpc_service(conn.2.clone(), health_client))
+            .await
+            .transpose()
+            .change_context(HealthCheckError::ConnectionError(
+                "error calling dynamic routing service".to_string(),
+            ))
+            .map_err(|err| logger::error!(error=?err))
+            .ok()
+            .flatten()
+            .is_some_and(|resp| resp.status == expected_status);
+
+        connection.and_then(|_conn| {
+            service_map.insert(
+                HealthCheckServices::DynamicRoutingService,
+                health_check_succeed,
+            )
+        });
+
+        Ok(service_map)
+    }
+
+    async fn get_response_from_grpc_service(
+        &self,
+        service: String,
+        client: Option<&HealthClient<Client>>,
+    ) -> HealthCheckResult<HealthCheckResponse> {
+        let request = tonic::Request::new(HealthCheckRequest { service });
+
+        let mut client = client
+            .ok_or(HealthCheckError::MissingFields(
+                "[health_client]".to_string(),
+            ))?
+            .clone();
+
+        let response = client
+            .check(request)
+            .await
+            .change_context(HealthCheckError::ConnectionError(
+                "Failed to call dynamic routing service".to_string(),
+            ))?
+            .into_inner();
+
+        Ok(response)
+    }
+}

crates/router/Cargo.toml

@@ -37,7 +37,7 @@ v2 = ["customer_v2", "payment_methods_v2", "common_default", "api_models/v2", "d
 v1 = ["common_default", "api_models/v1", "diesel_models/v1", "hyperswitch_domain_models/v1", "storage_impl/v1", "hyperswitch_interfaces/v1", "kgraph_utils/v1", "common_utils/v1"]
 customer_v2 = ["api_models/customer_v2", "diesel_models/customer_v2", "hyperswitch_domain_models/customer_v2", "storage_impl/customer_v2"]
 payment_methods_v2 = ["api_models/payment_methods_v2", "diesel_models/payment_methods_v2", "hyperswitch_domain_models/payment_methods_v2", "storage_impl/payment_methods_v2", "common_utils/payment_methods_v2"]
-dynamic_routing = ["external_services/dynamic_routing", "storage_impl/dynamic_routing"]
+dynamic_routing = ["external_services/dynamic_routing", "storage_impl/dynamic_routing", "api_models/dynamic_routing"]
 
 # Partial Auth
 # The feature reduces the overhead of the router authenticating the merchant for every request, and trusts on `x-merchant-id` header to be present in the request.

crates/router/src/core/health_check.rs

@@ -1,5 +1,7 @@
 #[cfg(feature = "olap")]
 use analytics::health_check::HealthCheck;
+#[cfg(feature = "dynamic_routing")]
+use api_models::health_check::HealthCheckMap;
 use api_models::health_check::HealthState;
 use error_stack::ResultExt;
 use router_env::logger;
@@ -28,6 +30,11 @@ pub trait HealthCheckInterface {
     async fn health_check_opensearch(
         &self,
     ) -> CustomResult<HealthState, errors::HealthCheckDBError>;
+
+    #[cfg(feature = "dynamic_routing")]
+    async fn health_check_grpc(
+        &self,
+    ) -> CustomResult<HealthCheckMap, errors::HealthCheckGRPCServiceError>;
 }
 
 #[async_trait::async_trait]
@@ -158,4 +165,20 @@ impl HealthCheckInterface for app::SessionState {
         logger::debug!("Outgoing request successful");
         Ok(HealthState::Running)
     }
+
+    #[cfg(feature = "dynamic_routing")]
+    async fn health_check_grpc(
+        &self,
+    ) -> CustomResult<HealthCheckMap, errors::HealthCheckGRPCServiceError> {
+        let health_client = &self.grpc_client.health_client;
+        let grpc_config = &self.conf.grpc_client;
+
+        let health_check_map = health_client
+            .perform_health_check(grpc_config)
+            .await
+            .change_context(errors::HealthCheckGRPCServiceError::FailedToCallService)?;
+
+        logger::debug!("Health check successful");
+        Ok(health_check_map)
+    }
 }

crates/router/src/routes/health.rs

@@ -95,6 +95,19 @@ async fn deep_health_check_func(
 
     logger::debug!("Analytics health check end");
 
+    logger::debug!("gRPC health check begin");
+
+    #[cfg(feature = "dynamic_routing")]
+    let grpc_health_check = state.health_check_grpc().await.map_err(|error| {
+        let message = error.to_string();
+        error.change_context(errors::ApiErrorResponse::HealthCheckError {
+            component: "gRPC services",
+            message,
+        })
+    })?;
+
+    logger::debug!("gRPC health check end");
+
     logger::debug!("Opensearch health check begin");
 
     #[cfg(feature = "olap")]
@@ -129,6 +142,8 @@ async fn deep_health_check_func(
         #[cfg(feature = "olap")]
         opensearch: opensearch_status.into(),
         outgoing_request: outgoing_check.into(),
+        #[cfg(feature = "dynamic_routing")]
+        grpc_health_check,
     };
 
     Ok(api::ApplicationResponse::Json(response))

crates/storage_impl/src/errors.rs

@@ -292,3 +292,9 @@ pub enum HealthCheckLockerError {
     #[error("Failed to establish Locker connection")]
     FailedToCallLocker,
 }
+
+#[derive(Debug, Clone, thiserror::Error)]
+pub enum HealthCheckGRPCServiceError {
+    #[error("Failed to establish connection with gRPC service")]
+    FailedToCallService,
+}

proto/health_check.proto

@@ -0,0 +1,21 @@
+syntax = "proto3";
+
+package grpc.health.v1;
+
+message HealthCheckRequest {
+  string service = 1;
+}
+
+message HealthCheckResponse {
+  enum ServingStatus {
+    UNKNOWN = 0;
+    SERVING = 1;
+    NOT_SERVING = 2;
+    SERVICE_UNKNOWN = 3;  // Used only by the Watch method.
+  }
+  ServingStatus status = 1;
+}
+
+service Health {
+  rpc Check(HealthCheckRequest) returns (HealthCheckResponse);
+}