README
¶
go-log 
Log is a generic logging library based on logrus (this may change in the future), that minimize the exposure of src-d projects to logrus or any other logging library, as well defines the standard for configuration and usage of the logging libraries in the organization.
Installation
The recommended way to install go-log is:
go get -u gopkg.in/src-d/go-log.v1/...
Configuration
The configuration should be done always using environment variables. The list of available variables is:
LOG_LEVEL: Reporting level, values are "info", "debug", "warning" or "error".LOG_FORMAT: Format of the log lines, values are "text", "json" or "fluentd", by default "text" is used. unless a terminal can't be detected, in this case, "json" is used instead.LOG_FIELDS: Fields in JSON or fluentd format to be included in all the loggers.LOG_FORCE_FORMAT: If true the fact of being in a terminal or not is ignored.
By default the logging is disabled if go-log is being executed in tests.
Usage
Basic usage
The most basic form of logging is made using the Infof, Debugf, Warningf
and Errorf functions at the top level of the packages.
log.Infof("The answer to life, the universe and everything is %d", 42)
// INFO The answer to life, the universe and everything is 42
These functions use the DefaultLogger a logger lazy instanced when this method
are called. This logger reads the configuration from the environment variables.
Logger instantiation
If you prefer to keep a reference to the Logger, in your packages or structs
to have more control over it (for example for tests). A default Logger, can
be instantiated using the New method.
logger := log.New(nil)
logger.Infof("The answer to life, the universe and everything is %d", 42)
// INFO The answer to life, the universe and everything is 42
Also, a new Logger can be created from other Logger in order to have
contextual information, using the method Logger.New
logger := log.New(nil)
authorLogger := logger.New(log.Field{"author": "Douglas Adams"})
bookLogger.Infof("The Hitchhiker's Guide to the Galaxy")
bookLogger.Infof("Life, the Universe and Everything")
// INFO The Hitchhiker's Guide to the Galaxy author=Douglas Adams
// INFO Life, the Universe and Everything author=Douglas Adams
Or if you just want to add contextual information Logger.New to one log line
you can use the Logger.With method.
logger := log.New(nil)
authorLogger := logger.New(log.Field{"author": "Douglas Adams"})
bookLogger.With(log.Fields{"isbn": "0-330-25864-8"}).Infof("The Hitchhiker's Guide to the Galaxy")
bookLogger.With(log.Fields{"isbn": "0-345-39182-9"}).Infof("Life, the Universe and Everything")
// INFO The Hitchhiker's Guide to the Galaxy author=Douglas Adams isbn=0-330-25864-8
// INFO Life, the Universe and Everything author=Douglas Adams isbn=0-345-39182-9
Logging errors
In go-log the errors are logged using the function Logger.Errorf:
logger, _ := log.New()
_, err := http.Get("https://en.wikipedia.org/wiki/Douglas_Adams")
if err != nil {
logger.Errorf(err, "unable to retrieve page")
}
License
Apache License Version 2.0, see LICENSE
Documentation
¶
Overview ¶
Package log is a generic logging library based on logrus (this may change in the future), that minimize the exposure of src-d projects to logrus or any other logging library, as well defines the standard for configuration and usage of the logging libraries in the organization.
Index ¶
Constants ¶
const ( // DebugLevel stands for debug logging level. DebugLevel = "debug" // InfoLevel stands for info logging level (default). InfoLevel = "info" // WarningLevel stands for warning logging level. WarningLevel = "warning" // ErrorLevel stands for error logging level. ErrorLevel = "error" // TextFormat stands for text logging format. TextFormat = "text" // JSONFormat stands for json logging format. JSONFormat = "json" // FluentdFormat stands for fluentd that can be parsed by Kubernetes and Google Container Engine. FluentdFormat = "fluentd" // DefaultLevel is the level used by LoggerFactory when Level is omitted. DefaultLevel = InfoLevel // DefaultFormat is the format used by LoggerFactory when Format is omitted. DefaultFormat = TextFormat )
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Logger ¶
type Logger interface {
// New returns a copy of the current logger, adding the given Fields.
New(Fields) Logger
// With returns a copy of the current logger, adding the given Fields.
// Alias of New, must be used when is chained with any message function.
With(Fields) Logger
// Debugf logs a message at level Debug.
Debugf(format string, args ...interface{})
// Infof logs a message at level Info.
Infof(format string, args ...interface{})
// Warningf logs a message at level Warning.
Warningf(format string, args ...interface{})
// Errorf logs an error with a message at level Error.
Errorf(err error, format string, args ...interface{})
}
Logger represents a generic logger, based on logrus.Logger
var DefaultLogger Logger
DefaultLogger logger used by the `log.Infof()`, `log.Debugf()`, `log.Warningf()` and `log.Error()` functions. The DefaultLogger is lazily instantiated if nil once this functions are called.
type LoggerFactory ¶
type LoggerFactory struct {
// Level as string, values are "info", "debug", "warning" or "error".
Level string
// Format as string, values are "text", "json" or "fluentnd", by default "text" is used.
// when a terminal is not detected "json" is used instead.
Format string
// Fields in JSON or fluentd format to be used by configured in the new Logger.
Fields string
// ForceFormat if true the fact of being in a terminal or not is ignored.
ForceFormat bool
}
LoggerFactory is a logger factory used to instanciate new Loggers, from string configuration, mainly coming from console flags.
var DefaultFactory *LoggerFactory
DefaultFactory logger used by the `log.New()` function. Pre-configured with the environment variables.
The environment variables are autogenerated from the `LoggerFactory` fields, with a prefix `log`, it means that three different variables are available `LOG_LEVEL`, `LOG_FORMAT`, `LOG_FIELDS`, for more information about the values please read the `LoggerFactory` documentation.
func (*LoggerFactory) ApplyToLogrus ¶
func (f *LoggerFactory) ApplyToLogrus() error
ApplyToLogrus configures the standard logrus Logger with the LoggerFactory values. Useful to propagate the configuration to third-party libraries using logrus.
Source Files