github.com/adityamillind98/nomad@v0.11.8/helper/testlog/testlog.go (about)

     1  // Package testlog creates a *log.Logger backed by *testing.T to ease logging
     2  // in tests. This allows logs from components being tested to only be printed
     3  // if the test fails (or the verbose flag is specified).
     4  package testlog
     5  
     6  import (
     7  	"bytes"
     8  	"io"
     9  	"log"
    10  	"os"
    11  
    12  	hclog "github.com/hashicorp/go-hclog"
    13  )
    14  
    15  // LogPrinter is the methods of testing.T (or testing.B) needed by the test
    16  // logger.
    17  type LogPrinter interface {
    18  	Logf(format string, args ...interface{})
    19  }
    20  
    21  // NewWriter creates a new io.Writer backed by a Logger.
    22  func NewWriter(t LogPrinter) io.Writer {
    23  	return os.Stderr
    24  }
    25  
    26  // NewPrefixWriter creates a new io.Writer backed by a Logger with a custom
    27  // prefix per Write.
    28  func NewPrefixWriter(t LogPrinter, prefix string) io.Writer {
    29  	return &prefixStderr{[]byte(prefix)}
    30  }
    31  
    32  // New returns a new test logger. See https://golang.org/pkg/log/#New
    33  func New(t LogPrinter, prefix string, flag int) *log.Logger {
    34  	return log.New(os.Stderr, prefix, flag)
    35  }
    36  
    37  // WithPrefix returns a new test logger with the Lmicroseconds flag set.
    38  func WithPrefix(t LogPrinter, prefix string) *log.Logger {
    39  	return New(t, prefix, log.Lmicroseconds)
    40  }
    41  
    42  // Logger returns a new test logger with the Lmicroseconds flag set and no
    43  // prefix.
    44  func Logger(t LogPrinter) *log.Logger {
    45  	return WithPrefix(t, "")
    46  }
    47  
    48  //HCLogger returns a new test hc-logger.
    49  func HCLogger(t LogPrinter) hclog.InterceptLogger {
    50  	level := hclog.Trace
    51  	envLogLevel := os.Getenv("NOMAD_TEST_LOG_LEVEL")
    52  	if envLogLevel != "" {
    53  		level = hclog.LevelFromString(envLogLevel)
    54  	}
    55  	opts := &hclog.LoggerOptions{
    56  		Level:           level,
    57  		Output:          os.Stderr,
    58  		IncludeLocation: true,
    59  	}
    60  	return hclog.NewInterceptLogger(opts)
    61  }
    62  
    63  type prefixStderr struct {
    64  	prefix []byte
    65  }
    66  
    67  // Write to stdout with a prefix per call containing non-whitespace characters.
    68  func (w *prefixStderr) Write(p []byte) (int, error) {
    69  	if len(p) == 0 {
    70  		return 0, nil
    71  	}
    72  
    73  	// Skip prefix if only writing whitespace
    74  	if len(bytes.TrimSpace(p)) > 0 {
    75  		_, err := os.Stderr.Write(w.prefix)
    76  		if err != nil {
    77  			return 0, err
    78  		}
    79  	}
    80  
    81  	return os.Stderr.Write(p)
    82  }