logs.go

Documentation: github.com/opencontainers/runc/libcontainer/logs

     1  package logs
     2  
     3  import (
     4  	"bufio"
     5  	"encoding/json"
     6  	"io"
     7  
     8  	"github.com/sirupsen/logrus"
     9  )
    10  
    11  func ForwardLogs(logPipe io.ReadCloser) chan error {
    12  	done := make(chan error, 1)
    13  	s := bufio.NewScanner(logPipe)
    14  
    15  	logger := logrus.StandardLogger()
    16  	if logger.ReportCaller {
    17  		// Need a copy of the standard logger, but with ReportCaller
    18  		// turned off, as the logs are merely forwarded and their
    19  		// true source is not this file/line/function.
    20  		logNoCaller := *logrus.StandardLogger()
    21  		logNoCaller.ReportCaller = false
    22  		logger = &logNoCaller
    23  	}
    24  
    25  	go func() {
    26  		for s.Scan() {
    27  			processEntry(s.Bytes(), logger)
    28  		}
    29  		if err := logPipe.Close(); err != nil {
    30  			logrus.Errorf("error closing log source: %v", err)
    31  		}
    32  		// The only error we want to return is when reading from
    33  		// logPipe has failed.
    34  		done <- s.Err()
    35  		close(done)
    36  	}()
    37  
    38  	return done
    39  }
    40  
    41  func processEntry(text []byte, logger *logrus.Logger) {
    42  	if len(text) == 0 {
    43  		return
    44  	}
    45  
    46  	var jl struct {
    47  		Level logrus.Level `json:"level"`
    48  		Msg   string       `json:"msg"`
    49  	}
    50  	if err := json.Unmarshal(text, &jl); err != nil {
    51  		logrus.Errorf("failed to decode %q to json: %v", text, err)
    52  		return
    53  	}
    54  
    55  	logger.Log(jl.Level, jl.Msg)
    56  }
    57
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