com.google.cloud.spring.autoconfigure.config.GoogleConfigPropertySourceLocator Maven / Gradle / Ivy

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/*
 * Copyright 2017-2019 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.google.cloud.spring.autoconfigure.config;

import com.google.api.gax.core.CredentialsProvider;
import com.google.auth.Credentials;
import com.google.cloud.spring.core.DefaultCredentialsProvider;
import com.google.cloud.spring.core.GcpProjectIdProvider;
import com.google.cloud.spring.core.UserAgentHeaderProvider;
import java.io.IOException;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import org.springframework.cloud.bootstrap.config.PropertySourceLocator;
import org.springframework.core.env.Environment;
import org.springframework.core.env.MapPropertySource;
import org.springframework.core.env.PropertySource;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.ResponseEntity;
import org.springframework.http.client.SimpleClientHttpRequestFactory;
import org.springframework.util.Assert;
import org.springframework.web.client.HttpClientErrorException;
import org.springframework.web.client.RestTemplate;

/**
 * Custom {@link PropertySourceLocator} for Google Cloud Runtime Configurator API.
 *
 * @since 1.1
 */
public class GoogleConfigPropertySourceLocator implements PropertySourceLocator {

  private static final String RUNTIMECONFIG_API_ROOT =
      "https://runtimeconfig.googleapis.com/v1beta1/";

  private static final String ALL_VARIABLES_PATH =
      "projects/{project}/configs/{name}_{profile}/variables?returnValues=true";

  private static final String PROPERTY_SOURCE_NAME = "spring-cloud-gcp";

  private static final String AUTHORIZATION_HEADER = "Authorization";

  private String projectId;

  private Credentials credentials;

  private String name;

  private String profile;

  private int timeout;

  private boolean enabled;

  public GoogleConfigPropertySourceLocator(
      GcpProjectIdProvider projectIdProvider,
      CredentialsProvider credentialsProvider,
      GcpConfigProperties gcpConfigProperties)
      throws IOException {
    Assert.notNull(gcpConfigProperties, "Google Config properties must not be null");

    if (gcpConfigProperties.isEnabled()) {
      Assert.notNull(credentialsProvider, "Credentials provider cannot be null");
      Assert.notNull(projectIdProvider, "Project ID provider cannot be null");
      this.credentials =
          gcpConfigProperties.getCredentials().hasKey()
              ? new DefaultCredentialsProvider(gcpConfigProperties).getCredentials()
              : credentialsProvider.getCredentials();
      this.projectId =
          (gcpConfigProperties.getProjectId() != null)
              ? gcpConfigProperties.getProjectId()
              : projectIdProvider.getProjectId();
      Assert.notNull(this.credentials, "Credentials must not be null");

      Assert.notNull(this.projectId, "Project ID must not be null");

      this.timeout = gcpConfigProperties.getTimeoutMillis();
      this.name = gcpConfigProperties.getName();
      this.profile = gcpConfigProperties.getProfile();
      this.enabled = gcpConfigProperties.isEnabled();
      Assert.notNull(this.name, "Config name must not be null");
      Assert.notNull(this.profile, "Config profile must not be null");
    }
  }

  private HttpEntity getAuthorizedRequest() throws IOException {
    HttpHeaders headers = new HttpHeaders();
    Map> credentialHeaders = this.credentials.getRequestMetadata();
    Assert.notNull(credentialHeaders, "No valid credential header(s) found");

    credentialHeaders.forEach((key, values) -> values.forEach(value -> headers.add(key, value)));

    Assert.isTrue(headers.containsKey(AUTHORIZATION_HEADER), "Authorization header required");

    // Adds product version header for usage metrics
    new UserAgentHeaderProvider(this.getClass()).getHeaders().forEach(headers::add);

    return new HttpEntity<>(headers);
  }

  GoogleConfigEnvironment getRemoteEnvironment() throws IOException, HttpClientErrorException {
    SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
    requestFactory.setReadTimeout(this.timeout);
    RestTemplate template = new RestTemplate(requestFactory);
    HttpEntity requestEntity = getAuthorizedRequest();
    ResponseEntity response =
        template.exchange(
            RUNTIMECONFIG_API_ROOT + ALL_VARIABLES_PATH,
            HttpMethod.GET,
            requestEntity,
            GoogleConfigEnvironment.class,
            this.projectId,
            this.name,
            this.profile);

    if (!response.getStatusCode().is2xxSuccessful()) {
      throw new HttpClientErrorException(
          response.getStatusCode(), "Invalid response from Runtime Configurator API");
    }
    return response.getBody();
  }

  @Override
  public PropertySource locate(Environment environment) {
    if (!this.enabled) {
      return new MapPropertySource(PROPERTY_SOURCE_NAME, Collections.emptyMap());
    }
    Map config;
    try {
      GoogleConfigEnvironment googleConfigEnvironment = getRemoteEnvironment();
      Assert.notNull(googleConfigEnvironment, "Configuration not in expected format.");
      config = googleConfigEnvironment.getConfig();
    } catch (Exception ex) {
      String message =
          String.format(
              "Error loading configuration for %s/%s_%s", this.projectId, this.name, this.profile);
      throw new RuntimeException(message, ex);
    }
    return new MapPropertySource(PROPERTY_SOURCE_NAME, config);
  }

  public String getProjectId() {
    return this.projectId;
  }
}