To install this package, clone it under your $GOPATH/src/ directory.
Package trace allows debugging programs via trace statements inserted in code. Sometimes you need to see the sequence in which functions are called, and stepping through each manually with a debugger is not the appropriate answer. If you've ever sprinkled "Printf" statements throughout your code to get insight into what's happenning, this package is strictly better: in addition to printing the messages you specify, it denotes the structure of the stack by appropriately indenting them (and indenting the names of the callers), and printing time stamps of when the trace calls occurred.
Tracing is as simple as inserting a Trace statements where you want to do the tracing. These statements will print all the currrent stack frames to the most recent previously traced stack frame that is on the current stack.
trace.Trace()
You may also pass printf-style arguments to Trace to display interesting state of your program:
trace("Label: my var=%v", myvar)
You should turn on tracing before the point in your program where you want to trace. If you want to trace a package init() function, turn it on there. This function call is idempotent. It is merely a shorthand for setting Global.On:
trace.On(true)
You may also turn off tracing at any point you wish:
trace.On(false)
In fact, you may change many of the seetings of an active Tracer object by modifying them directly. For example, to make global tracer only trace the last reported goroutine, use
trace.Global.LockGoRoutine = true
While in most cases you'll want to use the trace.Global logger (accessible directly and through the trace.Trace function), you can also create custom Tracer objects and use them via Tracer.Trace().
Tracer is concurrency-safe. When Trace() is called from a different goroutine than its previous call, it prints a warning about a goroutine switch. Optionally, it can print just the current goroutine stack frame including frames recorded earlier (if OnGoroutineSwitchPrintCurrentStack is set; default is false in Global), or print the entire history of the stack for this goroutine (if OnGoroutineSwitchPrintStackHistory is set; default is true in Global).
This is not an officially supported Google product.