package logging import ( "io" "io/ioutil" "log" "os" "strings" "syscall" "github.com/hashicorp/logutils" ) // These are the environmental variables that determine if we log, and if // we log whether or not the log should go to a file. const ( EnvLog = "TF_LOG" // Set to True EnvLogFile = "TF_LOG_PATH" // Set to a file ) var ValidLevels = []logutils.LogLevel{"TRACE", "DEBUG", "INFO", "WARN", "ERROR"} // LogOutput determines where we should send logs (if anywhere) and the log level. func LogOutput() (logOutput io.Writer, err error) { logOutput = ioutil.Discard logLevel := LogLevel() if logLevel == "" { return } logOutput = os.Stderr if logPath := os.Getenv(EnvLogFile); logPath != "" { var err error logOutput, err = os.OpenFile(logPath, syscall.O_CREAT|syscall.O_RDWR|syscall.O_APPEND, 0666) if err != nil { return nil, err } } // This was the default since the beginning logOutput = &logutils.LevelFilter{ Levels: ValidLevels, MinLevel: logutils.LogLevel(logLevel), Writer: logOutput, } return } // SetOutput checks for a log destination with LogOutput, and calls // log.SetOutput with the result. If LogOutput returns nil, SetOutput uses // ioutil.Discard. Any error from LogOutout is fatal. func SetOutput() { out, err := LogOutput() if err != nil { log.Fatal(err) } if out == nil { out = ioutil.Discard } log.SetOutput(out) } // LogLevel returns the current log level string based the environment vars func LogLevel() string { envLevel := os.Getenv(EnvLog) if envLevel == "" { return "" } logLevel := "TRACE" if isValidLogLevel(envLevel) { // allow following for better ux: info, Info or INFO logLevel = strings.ToUpper(envLevel) } else { log.Printf("[WARN] Invalid log level: %q. Defaulting to level: TRACE. Valid levels are: %+v", envLevel, ValidLevels) } return logLevel } // IsDebugOrHigher returns whether or not the current log level is debug or trace func IsDebugOrHigher() bool { level := string(LogLevel()) return level == "DEBUG" || level == "TRACE" } func isValidLogLevel(level string) bool { for _, l := range ValidLevels { if strings.ToUpper(level) == string(l) { return true } } return false }