open-consul/logger/logger.go

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package logger
import (
"fmt"
"io"
"path/filepath"
"strings"
"time"
"github.com/hashicorp/go-syslog"
"github.com/hashicorp/logutils"
"github.com/mitchellh/cli"
)
// Config is used to set up logging.
type Config struct {
// LogLevel is the minimum level to be logged.
LogLevel string
// EnableSyslog controls forwarding to syslog.
EnableSyslog bool
// SyslogFacility is the destination for syslog forwarding.
SyslogFacility string
//LogFilePath is the path to write the logs to the user specified file.
LogFilePath string
//LogRotateDuration is the user specified time to rotate logs
LogRotateDuration time.Duration
//LogRotateBytes is the user specified byte limit to rotate logs
LogRotateBytes int
//LogRotateMaxFiles is the maximum number of past archived log files to keep
LogRotateMaxFiles int
}
const (
// defaultRotateDuration is the default time taken by the agent to rotate logs
defaultRotateDuration = 24 * time.Hour
)
var (
logRotateDuration time.Duration
logRotateBytes int
)
// Setup is used to perform setup of several logging objects:
//
// * A LevelFilter is used to perform filtering by log level.
// * A GatedWriter is used to buffer logs until startup UI operations are
// complete. After this is flushed then logs flow directly to output
// destinations.
// * A LogWriter provides a mean to temporarily hook logs, such as for running
// a command like "consul monitor".
// * An io.Writer is provided as the sink for all logs to flow to.
//
// The provided ui object will get any log messages related to setting up
// logging itself, and will also be hooked up to the gated logger. The final bool
// parameter indicates if logging was set up successfully.
func Setup(config *Config, ui cli.Ui) (*logutils.LevelFilter, *GatedWriter, *LogWriter, io.Writer, bool) {
// The gated writer buffers logs at startup and holds until it's flushed.
logGate := &GatedWriter{
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Writer: &cli.UiWriter{Ui: ui},
}
// Set up the level filter.
logFilter := LevelFilter()
logFilter.MinLevel = logutils.LogLevel(strings.ToUpper(config.LogLevel))
logFilter.Writer = logGate
if !ValidateLevelFilter(logFilter.MinLevel, logFilter) {
ui.Error(fmt.Sprintf(
"Invalid log level: %s. Valid log levels are: %v",
logFilter.MinLevel, logFilter.Levels))
return nil, nil, nil, nil, false
}
// Set up syslog if it's enabled.
var syslog io.Writer
if config.EnableSyslog {
retries := 12
delay := 5 * time.Second
for i := 0; i <= retries; i++ {
l, err := gsyslog.NewLogger(gsyslog.LOG_NOTICE, config.SyslogFacility, "consul")
if err == nil {
syslog = &SyslogWrapper{l, logFilter}
break
}
ui.Error(fmt.Sprintf("Syslog setup error: %v", err))
if i == retries {
timeout := time.Duration(retries) * delay
ui.Error(fmt.Sprintf("Syslog setup did not succeed within timeout (%s).", timeout.String()))
return nil, nil, nil, nil, false
}
ui.Error(fmt.Sprintf("Retrying syslog setup in %s...", delay.String()))
time.Sleep(delay)
}
}
// Create a log writer, and wrap a logOutput around it
logWriter := NewLogWriter(512)
writers := []io.Writer{logFilter, logWriter}
var logOutput io.Writer
if syslog != nil {
writers = append(writers, syslog)
}
// Create a file logger if the user has specified the path to the log file
if config.LogFilePath != "" {
dir, fileName := filepath.Split(config.LogFilePath)
// If a path is provided but has no fileName a default is provided.
if fileName == "" {
fileName = "consul.log"
}
// Try to enter the user specified log rotation duration first
if config.LogRotateDuration != 0 {
logRotateDuration = config.LogRotateDuration
} else {
// Default to 24 hrs if no rotation period is specified
logRotateDuration = defaultRotateDuration
}
// User specified byte limit for log rotation if one is provided
if config.LogRotateBytes != 0 {
logRotateBytes = config.LogRotateBytes
}
logFile := &LogFile{
logFilter: logFilter,
fileName: fileName,
logPath: dir,
duration: logRotateDuration,
MaxBytes: logRotateBytes,
MaxFiles: config.LogRotateMaxFiles,
}
writers = append(writers, logFile)
}
logOutput = io.MultiWriter(writers...)
return logFilter, logGate, logWriter, logOutput, true
}