qrtt1/BYOGC4J

Build Your Own Google Client For Java

gcloud-java is not supported compute-engine api, and jcloud is too large for simple usage.

We just build a workable simple client from google-api-java-client.

How to use

Create And Register HttpClient

GoogleCredential googleCredential =
    GoogleCredential.fromStream(new FileInputStream(new File("json-key-file from service account")));

// grants scopes for http-client
googleCredential = googleCredential.createScoped(ComputeEnginsScopes.scopes());

// register the http-client to our GoogleComputeService object
GoogleComputeService api = new GoogleComputeService();
api.registerClient(ComputeEngine.class, googleCredential);

// create the Instances object
Instances instances = api.create(ComputeEngine.class, Instances.class);

String project = "your-project-id";
String zone = "asia-east1-b";

Param param = Param
        .create("name", "abce1")
        .add("machineType", "zones/asia-east1-b/machineTypes/n1-standard-1")
        .add("sourceImage",
                "https://www.googleapis.com/compute/v1/projects/ubuntu-os-cloud/global/images/ubuntu-1404-trusty-v20160314");

JsonObject result = instances.insert(project, zone, param);

Add new features

An example for ComputeEngine. We group the resources of a service in following structure.

Service ComputeEngine annotated with @RootUri
Resource Instances is just an java inteface with operations
any primitive parameter in an operation should be annoted with @Name, becasue we cannot know the name of the parameter after complied
any extra parameter in an operation can set by Param
an operation without the request body should be annotated with @Verb @PathParamsTemplate
an operation with the request body should be annotated with @Verb @PathParamsTemplate @RequestBodyTemplate

@RootUri(rootUrl = "https://www.googleapis.com", servicePath = "/compute/v1/projects")
public interface ComputeEngine {

    public interface Instances {

        @Verb(HttpMethod.POST)
        @PathParamsTemplate("/:project/zones/:zone/instances")
        @RequestBodyTemplate("/instances.insert.json")
        public JsonObject insert(@Name("project") String project, @Name("zone") String zone, Param param);

        @Verb(HttpMethod.GET)
        @PathParamsTemplate("/:project/zones/:zone/instances")
        public JsonObject list(@Name("project") String project, @Name("zone") String zone);

    }

}

Another example for CloudStorage:

@OptionalQueryParameters used by the optional URL parameters
We provide the Param... param for the optional parameters case

@RootUri(rootUrl = "https://www.googleapis.com", servicePath = "/storage/v1/b")
public interface CloudStorage {

    public interface Buckets {

        @Verb(HttpMethod.GET)
        @PathParamsTemplate("?project=:project")
        @OptionalQueryParameters({ "maxResults", "pageToken", "prefix", "projection" })
        public JsonObject list(@Name("project") String project, Param... param);

    }

    public interface Objects {

        @Verb(HttpMethod.GET)
        @PathParamsTemplate("/:bucket/o")
        @OptionalQueryParameters({ "delimiter", "maxResults", "pageToken", "prefix", "projection" })
        public JsonObject list(@Name("bucket") String bucket, Param... param);

    }

}

@PathParamsTemplate

@PathParamsTemplate("/:project/zones/:zone/instances")

In @PathParamsTemplate any string starts with : and following characters excludes :, / and & is a variable

@RequestBodyTemplate

@RequestBodyTemplate will set a classpath to the json template, the following example is the template of the Instances.insert operation. We use the ${...} format for variable notation.

{
  "name": "${name}",
  "machineType": "${machineType}",
  "networkInterfaces": [
    {
      "accessConfigs": [
        {
          "type": "ONE_TO_ONE_NAT",
          "name": "External NAT"
        }
      ]
    }
  ],
  "tags": {
    "items": [
    ]
  },
  "disks": [
    {
      "initializeParams": {
        "sourceImage": "${sourceImage}"
      },
      "boot": true,
      "autoDelete": true
    }
  ],
  "metadata": {
    "items": []
  },
  "serviceAccounts": [
    {
      "email": "default",
      "scopes": [
        "https://www.googleapis.com/auth/devstorage.read_only"
      ]
    }
  ]
}

qrtt1 / BYOGC4J