/
logging.go
125 lines (106 loc) · 3.62 KB
/
logging.go
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/* This file is part of copyondemand.
*
* Copyright © 2020 Datto, Inc.
* Author: Bryan Ehrlich <behrlich@datto.com>
*
* Licensed under the Apache Software License, Version 2.0
* Fedora-License-Identifier: ASL 2.0
* SPDX-2.0-License-Identifier: Apache-2.0
* SPDX-3.0-License-Identifier: Apache-2.0
*
* copyondemand is free software.
* For more information on the license, see LICENSE.
* For more information on free software, see <https://www.gnu.org/philosophy/free-sw.en.html>.
*
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package main
import (
"fmt"
"io/ioutil"
"log/syslog"
"os"
"github.com/sirupsen/logrus"
syslogrus "github.com/sirupsen/logrus/hooks/syslog"
)
const (
syslogTag = "copyondemand"
nbdLogField = "nbdDevice"
sourceFileLogField = "sourceFile"
backingFileLogField = "backingFile"
)
// fieldLogHook will provide a constant set of fields to logrus.WithFields, such that all messages contain these fields.
// Implements logrus.Hook
type fieldLogHook struct {
// fields will be passed as fields to all log entries that enter it
fields logrus.Fields
// levels will restrict this hook to certain levels. If null, the struct will hook to all log levels.
levels []logrus.Level
}
// Levels returns all of the levels at which this hook will be fired.
func (hook fieldLogHook) Levels() []logrus.Level {
if hook.levels != nil {
return hook.levels
}
return logrus.AllLevels
}
// Fire dumps all stored fields into the given the given Entry.
func (hook fieldLogHook) Fire(entry *logrus.Entry) error {
for key, value := range hook.fields {
entry.Data[key] = value
}
return nil
}
// setupLogging setups up all logging for this run of the utility.
func setupLogging(verbosity verbosityLevel, nbdDevice, sourceFileName, backingFileName string) error {
setupLogOutput(verbosity)
setupLogFormatting()
err := setupLogHooks(nbdDevice, sourceFileName, backingFileName)
if err != nil {
return fmt.Errorf("could not setup logging: %s", err)
}
return nil
}
// setupLogOutput sets up logging output based on whether or not debug is enabled
func setupLogOutput(verbosity verbosityLevel) {
if verbosity == verbosityNormal {
logrus.SetOutput(ioutil.Discard)
return
}
// If we have any level of verbosity, start piping things to stderr
logrus.SetOutput(os.Stderr)
// Any verbosity of very or higher (should one eventually exist) should emit debug logs.
if verbosity >= verbosityVery {
logrus.SetLevel(logrus.DebugLevel)
}
}
// setupLogFormatting sets the formatting for the logger.
func setupLogFormatting() {
formatter := &logrus.JSONFormatter{}
logrus.SetFormatter(formatter)
}
// setupLogHooks injects log hooks for the given information about this run of the utility.
func setupLogHooks(nbdDevice, sourceFileName, backingFileName string) error {
fields := logrus.Fields{
nbdLogField: nbdDevice,
sourceFileLogField: sourceFileName,
backingFileLogField: backingFileName,
}
hook := fieldLogHook{fields: fields}
logrus.AddHook(hook)
syslogHook, err := syslogrus.NewSyslogHook("", "", syslog.LOG_USER|syslog.LOG_INFO, syslogTag)
if err != nil {
return fmt.Errorf("could not setup syslog hook: %s", err)
}
logrus.AddHook(syslogHook)
return nil
}