src/main/java/com/google/devtools/build/lib/analysis/test/TestShardingStrategy.java

// Copyright 2020 The Bazel Authors. All rights reserved.
//
// 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.google.devtools.build.lib.analysis.test;

import com.google.common.base.Ascii;
import com.google.devtools.common.options.Converter;
import com.google.devtools.common.options.Converters.IntegerConverter;
import com.google.devtools.common.options.OptionsParsingException;

/** A strategy for running the same tests in many processes. */
interface TestShardingStrategy {
  int getNumberOfShards(int shardCountFromAttr);

  /** Converts to {@link TestShardingStrategy}. */
  final class ShardingStrategyConverter extends Converter.Contextless<TestShardingStrategy> {
    private static final String FORCED_PREFIX = "forced=";

    @Override
    public String getTypeDescription() {
      return "explicit, disabled or forced=k where k is the number of shards to enforce";
    }

    @Override
    public TestShardingStrategy convert(String input) throws OptionsParsingException {
      for (TestShardingStrategy value : TestShardingStrategyNotForced.values()) {
        if (Ascii.equalsIgnoreCase(value.toString(), input)) {
          return value;
        }
      }

      if (Ascii.toLowerCase(input).startsWith(FORCED_PREFIX)) {
        int forcedShardsCount =
            new IntegerConverter().convert(input.substring(FORCED_PREFIX.length()));
        if (forcedShardsCount < 0) {
          throw new OptionsParsingException("Forced shards count cannot be negative.");
        }

        return new TestShardingStrategyForced(forcedShardsCount);
      }

      throw new OptionsParsingException(
          "Not a valid test sharding strategy: '"
              + input
              + "' (should be "
              + getTypeDescription()
              + ")");
    }
  }
}