Add documentation for `grpc-health-check`

Signed-off-by: Teju Nareddy <nareddyt@google.com>

packages/grpc-health-check/README.md

@@ -0,0 +1,91 @@
+# grpc-health-check
+
+Health check client and service for use with gRPC-node.
+
+## Background
+
+This package exports both a client and server that adhere to the [gRPC Health Checking Protocol](https://github.com/grpc/grpc/blob/master/doc/health-checking.md).
+
+By using this package, clients and servers can rely on common proto and service definitions. This means:
+- Clients can use the generated stubs to health check _any_ server that adheres to the protocol.
+- Servers do not reimplement common logic for publishing health statuses.
+
+## Installation
+
+Use the package manager [npm](https://www.npmjs.com/get-npm) to install `grpc-health-check`.
+
+```bash
+npm install grpc-health-check
+```
+
+## Usage
+
+### Server
+
+Any gRPC-node server can use `grpc-health-check` to adhere to the gRPC Health Checking Protocol. 
+The following shows how this package can be added to a pre-existing gRPC server.
+
+```javascript 1.8
+// Import package
+let health = require('grpc-health-check');
+
+// Define service status map. Key is the service name, value is the corresponding status.
+// By convention, the empty string "" key represents that status of the entire server.
+const statusMap = {
+  "ServiceFoo": proto.grpc.health.v1.HealthCheckResponse.ServingStatus.SERVING,
+  "ServiceBar": proto.grpc.health.v1.HealthCheckResponse.ServingStatus.NOT_SERVING,
+  "": proto.grpc.health.v1.HealthCheckResponse.ServingStatus.NOT_SERVING,
+};
+
+// Construct the service implementation
+let healthImpl = new health.Implementation(statusMap);
+
+// Add the service and implementation to your pre-existing gRPC-node server
+server.addService(health.service, healthImpl);
+```
+
+Congrats! Your server now allows any client to run a health check against it.
+
+### Client
+
+Any gRPC-node client can use `grpc-health-check` to run health checks against other servers that follow the protocol.
+The following shows how this package can be used by a pre-existing gRPC client.
+
+```javascript 1.8
+// Import package
+let grpc = require('grpc');
+let health = require('grpc-health-check');
+
+// Create the client
+let healthClient = new health.Client('localhost:8082', grpc.credentials.createInsecure());
+
+// Define the request, which contains the service to health check
+// By convention, the empty string "" key represents that status of the entire server.
+let request = {
+  service: "",
+};
+
+// Define the callback
+function callback (error, status) {
+  if (error) {
+    console.error(error);
+    return;
+  }
+
+  console.log(status);
+}
+
+// Make the request
+healthClient.check(request, callback);
+```
+
+This should print out "NOT_SERVING" if used with the server above.
+
+## Contributing
+
+Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.
+
+Please make sure to update tests as appropriate.
+
+## License
+[Apache License 2.0](https://choosealicense.com/licenses/apache-2.0/)

packages/grpc-health-check/package.json

@@ -1,8 +1,8 @@
 {
   "name": "grpc-health-check",
-  "version": "1.7.0",
+  "version": "1.7.1",
   "author": "Google Inc.",
-  "description": "Health check service for use with gRPC",
+  "description": "Health check client and service for use with gRPC-node",
   "repository": {
     "type": "git",
     "url": "https://github.com/grpc/grpc-node.git"
@@ -22,6 +22,7 @@
   },
   "files": [
     "LICENSE",
+    "README.md",
     "health.js",
     "v1"
   ],