Files
mattermost/utils/logger/logger.go
2017-10-16 11:09:43 -04:00

230 lines
8.6 KiB
Go

// this is a new logger interface for mattermost
package logger
import (
"context"
"encoding/json"
"fmt"
"path/filepath"
"runtime"
l4g "github.com/alecthomas/log4go"
"strings"
"github.com/mattermost/mattermost-server/model"
"github.com/mattermost/mattermost-server/utils"
"github.com/pkg/errors"
)
// this pattern allows us to "mock" the underlying l4g code when unit testing
var logger l4g.Logger
var debugLog = l4g.Debug
var infoLog = l4g.Info
var errorLog = l4g.Error
func init() {
initL4g(utils.Cfg.LogSettings)
}
// listens for configuration changes that we might need to respond to
var configListenerID = utils.AddConfigListener(func(oldConfig *model.Config, newConfig *model.Config) {
infoLog("Configuration change detected, reloading log settings")
initL4g(newConfig.LogSettings)
})
// assumes that ../config.go::configureLog has already been called, and has in turn called l4g.close() to clean up
// any old filters that we might have previously created
func initL4g(logSettings model.LogSettings) {
// TODO: add support for newConfig.LogSettings.EnableConsole. Right now, ../config.go sets it up in its configureLog
// method. If we also set it up here, messages will be written to the console twice. Eventually, when all instances
// of l4g have been replaced by this logger, we can move that code to here
if logSettings.EnableFile {
level := l4g.DEBUG
if logSettings.FileLevel == "INFO" {
level = l4g.INFO
} else if logSettings.FileLevel == "WARN" {
level = l4g.WARNING
} else if logSettings.FileLevel == "ERROR" {
level = l4g.ERROR
}
// create a logger that writes JSON objects to a file, and override our log methods to use it
if logger != nil {
logger.Close()
}
logger = NewJSONFileLogger(level, utils.GetLogFileLocation(logSettings.FileLocation)+".jsonl")
debugLog = logger.Debug
infoLog = logger.Info
errorLog = logger.Error
}
}
// contextKey lets us add contextual information to log messages
type contextKey string
func (c contextKey) String() string {
return string(c)
}
const contextKeyUserID contextKey = contextKey("user_id")
const contextKeyRequestID contextKey = contextKey("request_id")
// any contextKeys added to this array will be serialized in every log message
var contextKeys = [2]contextKey{contextKeyUserID, contextKeyRequestID}
// WithUserId adds a user id to the specified context. If the returned Context is subsequently passed to a logging
// method, the user id will automatically be included in the logged message
func WithUserId(ctx context.Context, userID string) context.Context {
return context.WithValue(ctx, contextKeyUserID, userID)
}
// WithRequestId adds a request id to the specified context. If the returned Context is subsequently passed to a logging
// method, the request id will automatically be included in the logged message
func WithRequestId(ctx context.Context, requestID string) context.Context {
return context.WithValue(ctx, contextKeyRequestID, requestID)
}
// extracts known contextKey values from the specified Context and assembles them into the returned map
func serializeContext(ctx context.Context) map[string]string {
serialized := make(map[string]string)
for _, key := range contextKeys {
value, ok := ctx.Value(key).(string)
if ok {
serialized[string(key)] = value
}
}
return serialized
}
// Returns the path to the next file up the callstack that has a different name than this file
// in other words, finds the path to the file that is doing the logging.
// Removes machine-specific prefix, so returned path starts with /mattermost-server.
// Looks a maximum of 10 frames up the call stack to find a file that has a different name than this one.
func getCallerFilename() (string, error) {
_, currentFilename, _, ok := runtime.Caller(0)
if !ok {
return "", errors.New("Failed to traverse stack frame")
}
platformDirectory := currentFilename
for filepath.Base(platformDirectory) != "platform" {
platformDirectory = filepath.Dir(platformDirectory)
if platformDirectory == "." || platformDirectory == string(filepath.Separator) {
break
}
}
for i := 1; i < 10; i++ {
_, parentFilename, _, ok := runtime.Caller(i)
if !ok {
return "", errors.New("Failed to traverse stack frame")
} else if parentFilename != currentFilename && strings.Contains(parentFilename, platformDirectory) {
// trim parentFilename such that we return the path to parentFilename, relative to platformDirectory
return parentFilename[strings.LastIndex(parentFilename, platformDirectory)+len(platformDirectory)+1:], nil
}
}
return "", errors.New("Failed to traverse stack frame")
}
// creates a JSON representation of a log message
func serializeLogMessage(ctx context.Context, message string) string {
callerFilename, err := getCallerFilename()
if err != nil {
callerFilename = "Unknown"
}
bytes, err := json.Marshal(&struct {
Context map[string]string `json:"context"`
File string `json:"file"`
Message string `json:"message"`
}{
serializeContext(ctx),
callerFilename,
message,
})
if err != nil {
errorLog("Failed to serialize log message %v", message)
}
return string(bytes)
}
func formatMessage(args ...interface{}) string {
msg, ok := args[0].(string)
if !ok {
panic("Second argument is not of type string")
}
if len(args) > 1 {
variables := args[1:]
msg = fmt.Sprintf(msg, variables...)
}
return msg
}
// Debugc logs a debugLog level message, including context information that is stored in the first parameter.
// If two parameters are supplied, the second must be a message string, and will be logged directly.
// If more than two parameters are supplied, the second parameter must be a format string, and the remaining parameters
// must be the variables to substitute into the format string, following the convention of the fmt.Sprintf(...) function.
func Debugc(ctx context.Context, args ...interface{}) {
debugLog(func() string {
msg := formatMessage(args...)
return serializeLogMessage(ctx, msg)
})
}
// Debugf logs a debugLog level message.
// If one parameter is supplied, it must be a message string, and will be logged directly.
// If two or more parameters are specified, the first parameter must be a format string, and the remaining parameters
// must be the variables to substitute into the format string, following the convention of the fmt.Sprintf(...) function.
func Debugf(args ...interface{}) {
debugLog(func() string {
msg := formatMessage(args...)
return serializeLogMessage(context.Background(), msg)
})
}
// Infoc logs an infoLog level message, including context information that is stored in the first parameter.
// If two parameters are supplied, the second must be a message string, and will be logged directly.
// If more than two parameters are supplied, the second parameter must be a format string, and the remaining parameters
// must be the variables to substitute into the format string, following the convention of the fmt.Sprintf(...) function.
func Infoc(ctx context.Context, args ...interface{}) {
infoLog(func() string {
msg := formatMessage(args...)
return serializeLogMessage(ctx, msg)
})
}
// Infof logs an infoLog level message.
// If one parameter is supplied, it must be a message string, and will be logged directly.
// If two or more parameters are specified, the first parameter must be a format string, and the remaining parameters
// must be the variables to substitute into the format string, following the convention of the fmt.Sprintf(...) function.
func Infof(args ...interface{}) {
infoLog(func() string {
msg := formatMessage(args...)
return serializeLogMessage(context.Background(), msg)
})
}
// Errorc logs an error level message, including context information that is stored in the first parameter.
// If two parameters are supplied, the second must be a message string, and will be logged directly.
// If more than two parameters are supplied, the second parameter must be a format string, and the remaining parameters
// must be the variables to substitute into the format string, following the convention of the fmt.Sprintf(...) function.
func Errorc(ctx context.Context, args ...interface{}) {
errorLog(func() string {
msg := formatMessage(args...)
return serializeLogMessage(ctx, msg)
})
}
// Errorf logs an error level message.
// If one parameter is supplied, it must be a message string, and will be logged directly.
// If two or more parameters are specified, the first parameter must be a format string, and the remaining parameters
// must be the variables to substitute into the format string, following the convention of the fmt.Sprintf(...) function.
func Errorf(args ...interface{}) {
errorLog(func() string {
msg := formatMessage(args...)
return serializeLogMessage(context.Background(), msg)
})
}