Adding API management

Cloud Endpoints Frameworks provides API management features that are comparable to the features that the Extensible Service Proxy (ESP) provides for Cloud Endpoints. Endpoints Frameworks includes a built-in API gateway that intercepts all requests and performs any necessary checks, such as authentication, before forwarding the request to the API backend. When the backend responds, Endpoints Frameworks gathers and reports telemetry. You can view metrics for your API on the Endpoints > Services page in the Google Cloud console.

The API management features available in Endpoints Frameworks include:

For your API to be managed by Endpoints, you must deploy an OpenAPI document that describes your API using version 2.0 of the OpenAPI Specification. This page describes how to generate and deploy an OpenAPI document that enables Endpoints to manage your API.

If you don't add API management, your API still serves requests, but your API doesn't appear on the Endpoints > Services page in the Google Cloud console, and the functionality provided by Endpoints, such as logging, monitoring, and setting quotas, isn't available.

To add API management to your API:

Set up your Maven pom.xml file or your Gradle build.gradle file as described in Configuring the build files.
Make sure that you set the Google Cloud project ID in the build files.
Maven

Search for <endpoints.project.id>, and replace YOUR_PROJECT_ID with your Google Cloud project ID. For example:

<endpoints.project.id>example-project-12345</endpoints.project.id>
```
<endpoints.project.id>YOUR_PROJECT_ID</endpoints.project.id>
```
Gradle
1. Search for def projectId, and replace YOUR_PROJECT_ID with your Google Cloud project ID. For example:
  def projectId = 'example-project-12345'
2. Make sure your build.gradle file contains the replaceProjectId task, which sets the project ID in the appengine-web.xml and web.xml files.
  task replaceProjectId(type: Copy) { from 'src/main/webapp/WEB-INF/' include '*.xml' into "build/exploded-${archivesBaseName}/WEB-INF" expand(endpoints:[project:[id:projectId]]) filteringCharset = 'UTF-8' }

In your API project's web.xml file, add the API management servlet filter configuration:

<!-- Add a filter that fetches the service config from service management. -->
<filter>
    <filter-name>endpoints-api-configuration</filter-name>
    <filter-class>com.google.api.control.ServiceManagementConfigFilter</filter-class>
</filter>

<!-- Add a filter that performs Endpoints logging and monitoring. -->
<filter>
    <filter-name>endpoints-api-controller</filter-name>
    <filter-class>com.google.api.control.extensions.appengine.GoogleAppEngineControlFilter</filter-class>
    <init-param>
        <param-name>endpoints.projectId</param-name>
        <param-value>${endpoints.project.id}</param-value>
    </init-param>
    <init-param>
        <param-name>endpoints.serviceName</param-name>
        <param-value>${endpoints.project.id}.appspot.com</param-value>
    </init-param>
</filter>

<filter-mapping>
    <filter-name>endpoints-api-configuration</filter-name>
    <servlet-name>EndpointsServlet</servlet-name>
</filter-mapping>

<filter-mapping>
    <filter-name>endpoints-api-controller</filter-name>
    <servlet-name>EndpointsServlet</servlet-name>
</filter-mapping>

Modify your API project's build configuration:

Maven

Add the API management dependencies:

<dependency>
  <groupId>com.google.endpoints</groupId>
  <artifactId>endpoints-management-control-appengine-all</artifactId>
  <version>1.0.14</version>
</dependency>

Include the plugin that you can use to generate client libraries and the OpenAPI document, openapi.json:

<plugin>
  <groupId>com.google.cloud.tools</groupId>
  <artifactId>endpoints-framework-maven-plugin</artifactId>
  <version>2.1.0</version>
  <configuration>
    <!-- plugin configuration -->
    <hostname>${endpoints.project.id}.appspot.com</hostname>
  </configuration>
</plugin>

Gradle

Add the API management dependencies:

compile 'com.google.endpoints:endpoints-management-control-appengine:1.0.14'
compile 'com.google.endpoints:endpoints-framework-auth:1.0.14'

Declare the external dependency so that the plugin is retrieved from Maven Central:
```
classpath 'com.google.cloud.tools:endpoints-framework-gradle-plugin:2.1.0'
```
Use the server-side Endpoints Frameworks Gradle plugin, which generates the OpenAPI document:
```
apply plugin: 'com.google.cloud.tools.endpoints-framework-server'
```

Configure the name of your Endpoints service:

endpointsServer {
  // Endpoints Framework Plugin server-side configuration
  hostname = "${projectId}.appspot.com"
}

After modifying dependencies, clean your project and then build your API:
Maven
```
    mvn clean
    mvn package
```
Gradle
```
    gradle clean
    gradle build
```

Generate the OpenAPI document, openapi.json:

Maven

mvn endpoints-framework:openApiDocs

Gradle

gradle endpointsOpenApiDocs

Deploy the OpenAPI document:
```
 gcloud endpoints services deploy openapi.json
```
The first time you deploy openapi.json, a new Endpoints service is created with the name YOUR_PROJECT_ID.appspot.com. On successful completion, a line similar to the following displays the service configuration ID and the service name:
```
Service Configuration 2017-02-13r0 uploaded for service example-project-12345.appspot.com
```
In the preceding example, 2017-02-13r0 is the service configuration ID. The service configuration ID consists of a date stamp followed by a revision number. If you deploy openapi.json again, the revision number is incremented in the service configuration ID.

If you need to display the service configuration ID again, run the following command, but replace YOUR_PROJECT_ID with the project ID of your Google Cloud project:
```
gcloud endpoints configs list --service=YOUR_PROJECT_ID.appspot.com
```
You can create your own OpenAPI document and deploy it, rather than using a generated one. Simply replace openapi.json above with the path to your OpenAPI document. For more information on writing an OpenAPI document, see OpenAPI overview.

Edit your appengine-web.xml file to set the value for an environment variable:

<env-variables>
    <env-var name="ENDPOINTS_SERVICE_NAME" value="${endpoints.project.id}.appspot.com" />
</env-variables>

Replace ${endpoints.project.id} with your Google Cloud project ID. For example:

<env-var name="ENDPOINTS_SERVICE_NAME" value="example-project-12345.appspot.com" />

Redeploy your application.

Maven

mvn appengine:deploy

Gradle

gradle appengineDeploy

Test your API by making some requests to it.
To view your API metrics, open the Endpoints > Services page in the Google Cloud console for your project:

Go to the Endpoints Services page