github.com/leeprovoost/terraform@v0.6.10-0.20160119085442-96f3f76118e7/helper/logging/logging.go (about)

     1  package logging
     2  
     3  import (
     4  	"io"
     5  	"io/ioutil"
     6  	"log"
     7  	"os"
     8  	"strings"
     9  
    10  	"github.com/hashicorp/logutils"
    11  )
    12  
    13  // These are the environmental variables that determine if we log, and if
    14  // we log whether or not the log should go to a file.
    15  const (
    16  	EnvLog     = "TF_LOG"      // Set to True
    17  	EnvLogFile = "TF_LOG_PATH" // Set to a file
    18  )
    19  
    20  var validLevels = []logutils.LogLevel{"TRACE", "DEBUG", "INFO", "WARN", "ERROR"}
    21  
    22  // LogOutput determines where we should send logs (if anywhere) and the log level.
    23  func LogOutput() (logOutput io.Writer, err error) {
    24  	logOutput = ioutil.Discard
    25  	envLevel := os.Getenv(EnvLog)
    26  	if envLevel == "" {
    27  		return
    28  	}
    29  
    30  	logOutput = os.Stderr
    31  	if logPath := os.Getenv(EnvLogFile); logPath != "" {
    32  		var err error
    33  		logOutput, err = os.Create(logPath)
    34  		if err != nil {
    35  			return nil, err
    36  		}
    37  	}
    38  
    39  	// This was the default since the beginning
    40  	logLevel := logutils.LogLevel("TRACE")
    41  
    42  	if isValidLogLevel(envLevel) {
    43  		// allow following for better ux: info, Info or INFO
    44  		logLevel = logutils.LogLevel(strings.ToUpper(envLevel))
    45  	} else {
    46  		log.Printf("[WARN] Invalid log level: %q. Defaulting to level: TRACE. Valid levels are: %+v",
    47  			envLevel, validLevels)
    48  	}
    49  
    50  	logOutput = &logutils.LevelFilter{
    51  		Levels:   validLevels,
    52  		MinLevel: logLevel,
    53  		Writer:   logOutput,
    54  	}
    55  
    56  	return
    57  }
    58  
    59  func isValidLogLevel(level string) bool {
    60  	for _, l := range validLevels {
    61  		if strings.ToUpper(level) == string(l) {
    62  			return true
    63  		}
    64  	}
    65  
    66  	return false
    67  }