packer-cn/log.go

47 lines
1.0 KiB
Go

package main
import (
"bufio"
"fmt"
"io"
"os"
"strings"
)
// 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 = "PACKER_LOG" //Set to True
const EnvLogFile = "PACKER_LOG_PATH" //Set to a file
// logOutput determines where we should send logs (if anywhere).
func logOutput() (logOutput io.Writer, err error) {
logOutput = nil
if os.Getenv(EnvLog) != "" && os.Getenv(EnvLog) != "0" {
logOutput = os.Stderr
if logPath := os.Getenv(EnvLogFile); logPath != "" {
var err error
logOutput, err = os.Create(logPath)
if err != nil {
return nil, err
}
} else {
// no path; do a little light filtering to avoid double-dipping UI
// calls.
r, w := io.Pipe()
scanner := bufio.NewScanner(r)
go func(scanner *bufio.Scanner) {
for scanner.Scan() {
if strings.Contains(scanner.Text(), "ui:") {
continue
}
os.Stderr.WriteString(fmt.Sprint(scanner.Text() + "\n"))
}
}(scanner)
logOutput = w
}
}
return
}