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// Copyright (c) 2022, Google Inc.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
package runner
import (
"fmt"
"io/ioutil"
"os"
"strconv"
)
const (
shardStatusFileEnv = "TEST_SHARD_STATUS_FILE"
shardTotalEnv = "TEST_TOTAL_SHARDS"
shardIndexEnv = "TEST_SHARD_INDEX"
shardPrefix = "RUNNER_"
)
func init() {
// When run under `go test`, init() functions may be run twice if the
// test binary ends up forking and execing itself. Therefore we move
// the environment variables to names that don't interfere with Go's
// own support for sharding. If we recorded and erased them, then they
// wouldn't exist the second time the binary runs.
for _, key := range []string{shardStatusFileEnv, shardTotalEnv, shardIndexEnv} {
value := os.Getenv(key)
if len(value) > 0 {
os.Setenv(shardPrefix+key, value)
os.Setenv(key, "")
}
}
}
// getSharding returns the shard index and count, or zeros if sharding is not
// enabled.
func getSharding() (index, total int, err error) {
statusFile := os.Getenv(shardPrefix + shardStatusFileEnv)
totalNumStr := os.Getenv(shardPrefix + shardTotalEnv)
indexStr := os.Getenv(shardPrefix + shardIndexEnv)
if len(totalNumStr) == 0 || len(indexStr) == 0 {
return 0, 0, nil
}
totalNum, err := strconv.Atoi(totalNumStr)
if err != nil {
return 0, 0, fmt.Errorf("$%s is %q, but expected a number\n", shardTotalEnv, totalNumStr)
}
index, err = strconv.Atoi(indexStr)
if err != nil {
return 0, 0, fmt.Errorf("$%s is %q, but expected a number\n", shardIndexEnv, indexStr)
}
if index < 0 || index >= totalNum {
return 0, 0, fmt.Errorf("shard index/total of %d/%d is invalid\n", index, totalNum)
}
if len(statusFile) > 0 {
if err := ioutil.WriteFile(statusFile, nil, 0664); err != nil {
return 0, 0, err
}
}
return index, totalNum, nil
}