grpc: Docs for client.healthCheck method

Author: codebien

docs/sources/k6/next/javascript-api/k6-net-grpc/client/_index.md

@@ -16,6 +16,7 @@ aliases:
 | [Client.loadProtoset(protosetPath)](https://grafana.com/docs/k6/<K6_VERSION>/javascript-api/k6-net-grpc/client/client-loadprotoset) | Loads and parses the given protoset file to be made available for RPC requests.                                                                         |
 | [Client.connect(address [,params])](https://grafana.com/docs/k6/<K6_VERSION>/javascript-api/k6-net-grpc/client/client-connect)      | Opens a connection to the given gRPC server.                                                                                                            |
 | [Client.invoke(url, request [,params])](https://grafana.com/docs/k6/<K6_VERSION>/javascript-api/k6-net-grpc/client/client-invoke)   | Makes an unary RPC for the given service/method and returns a [Response](https://grafana.com/docs/k6/<K6_VERSION>/javascript-api/k6-net-grpc/response). |
+| [Client.healthCheck([service])](https://grafana.com/docs/k6/<K6_VERSION>/javascript-api/k6-net-grpc/client/client-health-check) | Check the status of the service using the [Health Checking](https://grpc.io/docs/guides/health-checking) protocol. |
 | [Client.close()](https://grafana.com/docs/k6/<K6_VERSION>/javascript-api/k6-net-grpc/client/client-close)                           | Close the connection to the gRPC service.                                                                                                               |
 
 ### Examples
@@ -36,7 +37,7 @@ export default () => {
 
   const response = client.invoke('quickpizza.GRPC/RatePizza', {
     ingredients: ['Tomatoes', 'Cheese'],
-    dough: 'Thin'
+    dough: 'Thin',
   });
   console.log(response.message.starsRating); // should print a number between 1-5
 

docs/sources/k6/next/javascript-api/k6-net-grpc/client/client-health-check.md

@@ -0,0 +1,48 @@
+---
+title: 'Client.healthCheck()'
+description: 'Check the health of a gRPC endpoint.'
+---
+
+# Client.healthCheck([service])
+
+Check the health status of the gRPC service using the gRPC [Health Checking](https://grpc.io/docs/guides/health-checking/) protocol.
+
+The method returns the health status of the provided service. If no service name is provided, it checks the overall server health.
+
+The health check response includes a `status` field that can be one of the following constants:
+
+- `HealthCheckServing`: The service is healthy and serving requests
+- `HealthCheckNotServing`: The service is not serving requests
+- `HealthCheckUnknown`: The health status is unknown
+
+### Example
+
+{{< code >}}
+
+```javascript
+import grpc from 'k6/net/grpc';
+import { check } from 'k6';
+
+const client = new grpc.Client();
+client.load([], 'routeguide.proto');
+
+export default () => {
+  client.connect('localhost:10000', { plaintext: true });
+
+  // Check overall server health
+  const res = client.healthCheck();
+
+  check(res, {
+    'server is healthy': (r) => r && r.status === grpc.StatusOK,
+    'health status is serving': (r) => r && r.message.status === grpc.HealthCheckServing,
+  });
+
+  // Check specific service health
+  const svcRes = client.healthCheck('my.service.Name');
+  console.log('Health status:', svcRes.message.status);
+
+  client.close();
+};
+```
+
+{{< /code >}}

docs/sources/k6/next/using-k6/protocols/grpc.md

@@ -263,7 +263,7 @@ It's important to note how k6 handles requests and messages. First, it tries to
 A limitation during this process is that the object you pass as a request/message must be serializable. That means structs like `Map` don't work.
 
 The benefit of using `protojson` is the canonical JSON encoding support. The [Protocol Buffers documentation](https://protobuf.dev/programming-guides/proto3/#json) describes this mapping.
-Also note that according to [ProtoJSON docs](https://protobuf.dev/programming-guides/json/), the JSON value of a non-numeric float (e.g. `NaN` or `Infinity`) will be their equivalent string representation. 
+Also note that according to [ProtoJSON docs](https://protobuf.dev/programming-guides/json/), the JSON value of a non-numeric float (e.g. `NaN` or `Infinity`) will be their equivalent string representation.
 
 #### Examples
 
@@ -341,3 +341,9 @@ const respWithID = client.invoke('testing.Service/Test', { id: 123 });
 ```
 
 {{< /code >}}
+
+## Health Checking protocol
+
+There is a dedicated support for the [Health Checking](https://grpc.io/docs/guides/health-checking) protocol, which provides a standard way to check if a gRPC service is healthy and ready to serve requests. It eliminates the need to use the generic `invoke` method for health checks.
+
+The [Client.healthCheck()](https://grafana.com/docs/k6/<K6_VERSION>/javascript-api/k6-net-grpc/client/client-health-check) method implements this protocol and returns the health status of the specified service. If no service name is provided, it checks the overall server health.