go.uber.org/yarpc@v1.72.1/internal/shard/main.go (about)

     1  // Copyright (c) 2022 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package main
    22  
    23  import (
    24  	"fmt"
    25  	"io"
    26  	"log"
    27  	"os"
    28  	"strconv"
    29  )
    30  
    31  // Shards a list of files over a distribution defined by totalShards.
    32  // Useful for splitting work and running tests in parallel.
    33  var usage = fmt.Sprintf("Usage: %s shardNum totalShards args...", os.Args[0])
    34  
    35  func main() {
    36  	if err := do(os.Args[1:], os.Stdout); err != nil {
    37  		log.Fatal(err)
    38  	}
    39  }
    40  
    41  func do(args []string, writer io.Writer) error {
    42  	if len(args) < 2 {
    43  		return fmt.Errorf(usage)
    44  	}
    45  	shardNum, err := strconv.Atoi(args[0])
    46  	if err != nil {
    47  		return fmt.Errorf("%v\n%s", err, usage)
    48  	}
    49  	totalShards, err := strconv.Atoi(args[1])
    50  	if err != nil {
    51  		return fmt.Errorf("%v\n%s", err, usage)
    52  	}
    53  	for i := 2; i < len(args); i++ {
    54  		if (((i - 2) % totalShards) + 1) == shardNum {
    55  			if i != 2 {
    56  				fmt.Fprint(writer, " ")
    57  			}
    58  			fmt.Fprint(writer, args[i])
    59  		}
    60  	}
    61  	return nil
    62  }