slog.go

// Copyright 2017 Inca Roads LLC.  All rights reserved.
// Use of this source code is governed by licenses granted by the
// copyright holder including that found in the LICENSE file.

// Server log support
package main

import (
	"fmt"
	"hash/crc32"
	"os"
	"strings"
	"time"
)

// ServerLogFilename gets the current log file name for the current instance
func ServerLogFilename(extension string) string {
	prefix := time.Now().UTC().Format("2006-01-")
	filename := prefix + TTServeInstanceID + extension
	return filename
}

// ServerLogSecret gets secret that only allows the URLs from the Slack command to function
func ServerLogSecret() string {
	timestr := ControlFileTime(TTServerSlackCommandControlFile, "").Format(logDateFormat)
	checksum := crc32.ChecksumIEEE([]byte(timestr))
	checkstr := fmt.Sprintf("%d", checksum)
	return checkstr
}

// ServerLog logs a string to the instance's log file
func ServerLog(sWithoutDate string) {

	// Add a standard header unless it begins with a newline
	s := sWithoutDate
	if !strings.HasPrefix(sWithoutDate, "\n") {
		s = fmt.Sprintf("%s %s", LogTime(), sWithoutDate)
	}

	// Print it to the console
	fmt.Printf("%s", s)

	// Open it
	file := SafecastDirectory() + TTServerLogPath + "/" + ServerLogFilename(".log")
	fd, err := os.OpenFile(file, os.O_WRONLY|os.O_APPEND, 0666)
	if err != nil {

		// Don't attempt to create it if it already exists
		_, err2 := os.Stat(file)
		if err2 == nil {
			fmt.Printf("ServerLogging: Can't log to %s: %s\n", file, err)
			return
		}
		if err2 == nil {
			if !os.IsNotExist(err2) {
				fmt.Printf("ServerLogging: Ignoring attempt to create %s: %s\n", file, err2)
				return
			}
		}

		// Attempt to create the file because it doesn't already exist
		fd, err = os.OpenFile(file, os.O_RDWR|os.O_APPEND|os.O_CREATE, 0666)
		if err != nil {
			fmt.Printf("ServerLogging: error creating file %s: %s\n", file, err)
			return
		}
	}

	// Append it
	fd.WriteString(s)

	// Close and exit
	fd.Close()

}