github.com/kchristidis/fabric@v1.0.4-0.20171028114726-837acd08cde1/core/chaincode/platforms/golang/list.go (about)

     1  /*
     2  Copyright 2017 - Greg Haskins <gregory.haskins@gmail.com>
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8  		 http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package golang
    18  
    19  import (
    20  	"bytes"
    21  	"errors"
    22  	"fmt"
    23  	"os/exec"
    24  	"strings"
    25  	"time"
    26  )
    27  
    28  //runProgram non-nil Env, timeout (typically secs or millisecs), program name and args
    29  func runProgram(env Env, timeout time.Duration, pgm string, args ...string) ([]byte, error) {
    30  	if env == nil {
    31  		return nil, fmt.Errorf("<%s, %v>: nil env provided", pgm, args)
    32  	}
    33  	var stdOut bytes.Buffer
    34  	var stdErr bytes.Buffer
    35  
    36  	cmd := exec.Command(pgm, args...)
    37  	cmd.Env = flattenEnv(env)
    38  	cmd.Stdout = &stdOut
    39  	cmd.Stderr = &stdErr
    40  	err := cmd.Start()
    41  
    42  	// Create a go routine that will wait for the command to finish
    43  	done := make(chan error, 1)
    44  	go func() {
    45  		done <- cmd.Wait()
    46  	}()
    47  
    48  	select {
    49  	case <-time.After(timeout):
    50  		if err = cmd.Process.Kill(); err != nil {
    51  			return nil, fmt.Errorf("<%s, %v>: failed to kill: %s", pgm, args, err)
    52  		} else {
    53  			return nil, errors.New(fmt.Sprintf("<%s, %v>: timeout(%d msecs)", pgm, args, timeout/time.Millisecond))
    54  		}
    55  	case err = <-done:
    56  		if err != nil {
    57  			return nil, fmt.Errorf("<%s, %v>: failed with error: \"%s\"\n%s", pgm, args, err, string(stdErr.Bytes()))
    58  		}
    59  
    60  		return stdOut.Bytes(), nil
    61  	}
    62  }
    63  
    64  // Logic inspired by: https://dave.cheney.net/2014/09/14/go-list-your-swiss-army-knife
    65  func list(env Env, template, pkg string) ([]string, error) {
    66  	if env == nil {
    67  		env = getEnv()
    68  	}
    69  
    70  	lst, err := runProgram(env, 60*time.Second, "go", "list", "-f", template, pkg)
    71  	if err != nil {
    72  		return nil, err
    73  	}
    74  
    75  	return strings.Split(strings.Trim(string(lst), "\n"), "\n"), nil
    76  }
    77  
    78  func listDeps(env Env, pkg string) ([]string, error) {
    79  	return list(env, "{{ join .Deps \"\\n\"}}", pkg)
    80  }
    81  
    82  func listImports(env Env, pkg string) ([]string, error) {
    83  	return list(env, "{{ join .Imports \"\\n\"}}", pkg)
    84  }