1// Copyright (c) 2022, Google Inc. 2// 3// Permission to use, copy, modify, and/or distribute this software for any 4// purpose with or without fee is hereby granted, provided that the above 5// copyright notice and this permission notice appear in all copies. 6// 7// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 8// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 9// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 10// SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 11// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION 12// OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN 13// CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 14 15package runner 16 17import ( 18 "fmt" 19 "io/ioutil" 20 "os" 21 "strconv" 22) 23 24const ( 25 shardStatusFileEnv = "TEST_SHARD_STATUS_FILE" 26 shardTotalEnv = "TEST_TOTAL_SHARDS" 27 shardIndexEnv = "TEST_SHARD_INDEX" 28 shardPrefix = "RUNNER_" 29) 30 31func init() { 32 // When run under `go test`, init() functions may be run twice if the 33 // test binary ends up forking and execing itself. Therefore we move 34 // the environment variables to names that don't interfere with Go's 35 // own support for sharding. If we recorded and erased them, then they 36 // wouldn't exist the second time the binary runs. 37 for _, key := range []string{shardStatusFileEnv, shardTotalEnv, shardIndexEnv} { 38 value := os.Getenv(key) 39 if len(value) > 0 { 40 os.Setenv(shardPrefix+key, value) 41 os.Setenv(key, "") 42 } 43 } 44} 45 46// getSharding returns the shard index and count, or zeros if sharding is not 47// enabled. 48func getSharding() (index, total int, err error) { 49 statusFile := os.Getenv(shardPrefix + shardStatusFileEnv) 50 totalNumStr := os.Getenv(shardPrefix + shardTotalEnv) 51 indexStr := os.Getenv(shardPrefix + shardIndexEnv) 52 if len(totalNumStr) == 0 || len(indexStr) == 0 { 53 return 0, 0, nil 54 } 55 56 totalNum, err := strconv.Atoi(totalNumStr) 57 if err != nil { 58 return 0, 0, fmt.Errorf("$%s is %q, but expected a number\n", shardTotalEnv, totalNumStr) 59 } 60 61 index, err = strconv.Atoi(indexStr) 62 if err != nil { 63 return 0, 0, fmt.Errorf("$%s is %q, but expected a number\n", shardIndexEnv, indexStr) 64 } 65 66 if index < 0 || index >= totalNum { 67 return 0, 0, fmt.Errorf("shard index/total of %d/%d is invalid\n", index, totalNum) 68 } 69 70 if len(statusFile) > 0 { 71 if err := ioutil.WriteFile(statusFile, nil, 0664); err != nil { 72 return 0, 0, err 73 } 74 } 75 76 return index, totalNum, nil 77} 78