The logging library used by go-ipfs
It currently uses a modified version of go-logging to implement the standard printf-style log output.
go get github.com/ipfs/go-logOnce the pacakge is imported under the name logging, an instance of EventLogger can be created like so:
var log = logging.Logger("subsystem name")It can then be used to emit log messages, either plain printf-style messages at six standard levels or structured messages using Start, StartFromParentState, Finish and FinishWithErr methods.
func (s *Session) GetBlock(ctx context.Context, c *cid.Cid) (blk blocks.Block, err error) {
// Starts Span called "Session.GetBlock", associates with `ctx`
ctx = log.Start(ctx, "Session.GetBlock")
// defer so `blk` and `err` can be evaluated after call
defer func() {
// tag span associated with `ctx`
log.SetTags(ctx, map[string]interface{}{
"cid": c,
"block", blk,
})
// if err is non-nil tag the span with an error
log.FinishWithErr(ctx, err)
}()
if shouldStartSomething() {
// log message on span associated with `ctx`
log.LogKV(ctx, "startSomething", true)
}
...
}go-log wraps the opentracing-go methods - StartSpan, Finish, LogKV, and SetTag.
go-log implements its own tracer - loggabletracer - based on the basictracer-go implementation. If there is an active WriterGroup the loggabletracer will record span data to the WriterGroup. An example of this can be seen in the log tail command of go-ipfs.
Third party tracers may be used by calling opentracing.SetGlobalTracer() with your desired tracing implementation. An example of this can be seen using the go-jaeger-plugin and the go-ipfs tracer plugin
Feel free to join in. All welcome. Open an issue!
This repository falls under the IPFS Code of Conduct.
MIT