vendor/github.com/hashicorp/terraform/helper/logging/logging.go

   1 package logging
   2
   3 import (
   4         "io"
   5         "io/ioutil"
   6         "log"
   7         "os"
   8         "strings"
   9         "syscall"
  10
  11         "github.com/hashicorp/logutils"
  12 )
  13
  14 // These are the environmental variables that determine if we log, and if
  15 // we log whether or not the log should go to a file.
  16 const (
  17         EnvLog     = "TF_LOG"      // Set to True
  18         EnvLogFile = "TF_LOG_PATH" // Set to a file
  19 )
  20
  21 var validLevels = []logutils.LogLevel{"TRACE", "DEBUG", "INFO", "WARN", "ERROR"}
  22
  23 // LogOutput determines where we should send logs (if anywhere) and the log level.
  24 func LogOutput() (logOutput io.Writer, err error) {
  25         logOutput = ioutil.Discard
  26
  27         logLevel := LogLevel()
  28         if logLevel == "" {
  29                 return
  30         }
  31
  32         logOutput = os.Stderr
  33         if logPath := os.Getenv(EnvLogFile); logPath != "" {
  34                 var err error
  35                 logOutput, err = os.OpenFile(logPath, syscall.O_CREAT|syscall.O_RDWR|syscall.O_APPEND, 0666)
  36                 if err != nil {
  37                         return nil, err
  38                 }
  39         }
  40
  41         // This was the default since the beginning
  42         logOutput = &logutils.LevelFilter{
  43                 Levels:   validLevels,
  44                 MinLevel: logutils.LogLevel(logLevel),
  45                 Writer:   logOutput,
  46         }
  47
  48         return
  49 }
  50
  51 // SetOutput checks for a log destination with LogOutput, and calls
  52 // log.SetOutput with the result. If LogOutput returns nil, SetOutput uses
  53 // ioutil.Discard. Any error from LogOutout is fatal.
  54 func SetOutput() {
  55         out, err := LogOutput()
  56         if err != nil {
  57                 log.Fatal(err)
  58         }
  59
  60         if out == nil {
  61                 out = ioutil.Discard
  62         }
  63
  64         log.SetOutput(out)
  65 }
  66
  67 // LogLevel returns the current log level string based the environment vars
  68 func LogLevel() string {
  69         envLevel := os.Getenv(EnvLog)
  70         if envLevel == "" {
  71                 return ""
  72         }
  73
  74         logLevel := "TRACE"
  75         if isValidLogLevel(envLevel) {
  76                 // allow following for better ux: info, Info or INFO
  77                 logLevel = strings.ToUpper(envLevel)
  78         } else {
  79                 log.Printf("[WARN] Invalid log level: %q. Defaulting to level: TRACE. Valid levels are: %+v",
  80                         envLevel, validLevels)
  81         }
  82
  83         return logLevel
  84 }
  85
  86 // IsDebugOrHigher returns whether or not the current log level is debug or trace
  87 func IsDebugOrHigher() bool {
  88         level := string(LogLevel())
  89         return level == "DEBUG" || level == "TRACE"
  90 }
  91
  92 func isValidLogLevel(level string) bool {
  93         for _, l := range validLevels {
  94                 if strings.ToUpper(level) == string(l) {
  95                         return true
  96                 }
  97         }
  98
  99         return false
 100 }