src/main/java/com/googlesource/gerrit/plugins/replication/pull/api/FetchAction.java

// Copyright (C) 2020 The Android Open Source Project
//
// 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
//
// http://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.googlesource.gerrit.plugins.replication.pull.api;

import static com.google.common.base.Preconditions.checkState;

import com.google.common.base.Strings;
import com.google.gerrit.entities.Project;
import com.google.gerrit.extensions.registration.DynamicItem;
import com.google.gerrit.extensions.restapi.AuthException;
import com.google.gerrit.extensions.restapi.BadRequestException;
import com.google.gerrit.extensions.restapi.Response;
import com.google.gerrit.extensions.restapi.RestApiException;
import com.google.gerrit.extensions.restapi.RestModifyView;
import com.google.gerrit.extensions.restapi.UnprocessableEntityException;
import com.google.gerrit.server.config.UrlFormatter;
import com.google.gerrit.server.git.WorkQueue;
import com.google.gerrit.server.git.WorkQueue.Task;
import com.google.gerrit.server.ioutil.HexFormat;
import com.google.gerrit.server.project.ProjectResource;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import com.googlesource.gerrit.plugins.replication.pull.api.FetchAction.Input;
import com.googlesource.gerrit.plugins.replication.pull.api.FetchJob.Factory;
import com.googlesource.gerrit.plugins.replication.pull.api.exception.RemoteConfigurationMissingException;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.TimeoutException;
import java.util.stream.Collectors;
import java.util.stream.Stream;
import org.eclipse.jgit.errors.TransportException;

@Singleton
public class FetchAction implements RestModifyView<ProjectResource, Input> {
  private final FetchCommand command;
  private final WorkQueue workQueue;
  private final DynamicItem<UrlFormatter> urlFormatter;
  private final FetchPreconditions preConditions;
  private final Factory fetchJobFactory;

  @Inject
  public FetchAction(
      FetchCommand command,
      WorkQueue workQueue,
      DynamicItem<UrlFormatter> urlFormatter,
      FetchPreconditions preConditions,
      FetchJob.Factory fetchJobFactory) {
    this.command = command;
    this.workQueue = workQueue;
    this.urlFormatter = urlFormatter;
    this.preConditions = preConditions;
    this.fetchJobFactory = fetchJobFactory;
  }

  public static class Input {
    public String label;
    public String refName;
    public boolean async;
  }

  public static class BatchInput {
    public String label;
    public Set<String> refsNames;
    public boolean async;

    static BatchInput fromInput(Input... input) {
      BatchInput batchInput = new BatchInput();
      batchInput.async = input[0].async;
      batchInput.label = input[0].label;
      batchInput.refsNames = Stream.of(input).map(i -> i.refName).collect(Collectors.toSet());
      return batchInput;
    }
  }

  @Override
  public Response<?> apply(ProjectResource resource, Input input) throws RestApiException {
    return apply(resource, BatchInput.fromInput(input));
  }

  public Response<?> apply(ProjectResource resource, BatchInput batchInput)
      throws RestApiException {

    if (!preConditions.canCallFetchApi()) {
      throw new AuthException("not allowed to call fetch command");
    }
    try {
      if (Strings.isNullOrEmpty(batchInput.label)) {
        throw new BadRequestException("Source label cannot be null or empty");
      }

      if (batchInput.refsNames.isEmpty()) {
        throw new BadRequestException("Ref-update refname cannot be null or empty");
      }

      for (String refName : batchInput.refsNames) {
        if (Strings.isNullOrEmpty(refName)) {
          throw new BadRequestException("Ref-update refname cannot be null or empty");
        }
      }

      if (batchInput.async) {
        return applyAsync(resource.getNameKey(), batchInput);
      }
      return applySync(resource.getNameKey(), batchInput);
    } catch (InterruptedException
        | ExecutionException
        | IllegalStateException
        | TimeoutException
        | TransportException e) {
      throw RestApiException.wrap(e.getMessage(), e);
    } catch (RemoteConfigurationMissingException e) {
      throw new UnprocessableEntityException(e.getMessage());
    }
  }

  private Response<?> applySync(Project.NameKey project, BatchInput input)
      throws InterruptedException, ExecutionException, RemoteConfigurationMissingException,
          TimeoutException, TransportException {
    command.fetchSync(project, input.label, input.refsNames);
    return Response.created(input);
  }

  @SuppressWarnings("unchecked")
  private Response.Accepted applyAsync(Project.NameKey project, BatchInput batchInput) {
    WorkQueue.Task<Void> task = null;
    Optional<String> url;

    for (String refName : batchInput.refsNames) {
      Input input = new Input();
      input.label = batchInput.label;
      input.async = batchInput.async;
      input.refName = refName;
      task =
          (Task<Void>)
              workQueue
                  .getDefaultQueue()
                  .submit(
                      fetchJobFactory.create(
                          project, input, PullReplicationApiRequestMetrics.get()));
    }
    url =
        urlFormatter
            .get()
            .getRestUrl("a/config/server/tasks/" + HexFormat.fromInt(task.getTaskId()));
    // We're in a HTTP handler, so must be present.
    checkState(url.isPresent());
    return Response.accepted(url.get());
  }
}