open-consul/logging/logger.go

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package logging
import (
"fmt"
"io"
"path/filepath"
"time"
"github.com/hashicorp/go-hclog"
gsyslog "github.com/hashicorp/go-syslog"
)
// Config is used to set up logging.
type Config struct {
// LogLevel is the minimum level to be logged.
LogLevel string
// LogJSON controls outputing logs in a JSON format.
LogJSON bool
// Name is the name the returned logger will use to prefix log lines.
Name 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
)
type LogSetupErrorFn func(string)
// Setup is used to perform setup of several logging objects:
//
// * A hclog.Logger is used to perform filtering by log level and write to io.Writer.
// * A GatedWriter is used to buffer logs until startup UI operations are
// complete. After this is flushed then logs flow directly to output
// destinations.
// * 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, writers []io.Writer) (hclog.InterceptLogger, error) {
if !ValidateLogLevel(config.LogLevel) {
return nil, fmt.Errorf("Invalid log level: %s. Valid log levels are: %v",
config.LogLevel,
allowedLogLevels)
}
// 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}
break
}
if i == retries {
timeout := time.Duration(retries) * delay
return nil, fmt.Errorf("Syslog setup did not succeed within timeout (%s).", timeout.String())
}
time.Sleep(delay)
}
}
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{
fileName: fileName,
logPath: dir,
duration: logRotateDuration,
MaxBytes: logRotateBytes,
MaxFiles: config.LogRotateMaxFiles,
}
if err := logFile.openNew(); err != nil {
return nil, fmt.Errorf("Failed to setup logging: %w", err)
}
writers = append(writers, logFile)
}
logger := hclog.NewInterceptLogger(&hclog.LoggerOptions{
Level: LevelFromString(config.LogLevel),
Name: config.Name,
Output: io.MultiWriter(writers...),
JSONFormat: config.LogJSON,
})
return logger, nil
}