Delve

What is Delve?

Delve is a (Beta) Go debugger, written in Go.

This project is currently in beta. Most of the functionality is there, but there are various improvements to be made.

Building

Delve requires Go 1.4 to build, and currently only supports Linux, with OS X support coming soon.

go get -u github.com/derekparker/delve/cmd/dlv

You will need readline installed on your system. With apt simply: sudo apt-get install libreadline-dev .

Features

• Attach to an already running process
• Launch a process and begin debug session
• Set breakpoints, single step, step over functions, print variable contents, print thread and goroutine information

Usage

The debugger can be launched in three ways:

• Compile, run, and attach in one step:

  $ dlv -run
  

• Provide the name of the program you want to debug, and the debugger will launch it for you.

  $ dlv path/to/program
  

• Provide the pid of a currently running process, and the debugger will attach and begin the session.

  $ sudo dlv -pid 44839
  

Breakpoints

Delve can insert breakpoints via the breakpoint command once inside a debug session, however for ease of debugging, you can also call runtime.Breakpoint() and Delve will handle the breakpoint and stop the program at the next source line.

Commands

Once inside a debugging session, the following commands may be used:

• break - Set break point at the entry point of a function, or at a specific file/line. Example: break foo.go:13.

• continue - Run until breakpoint or program termination.

• step - Single step through program.

• next - Step over to next source line.

• threads - Print status of all traced threads.

• goroutines - Print status of all goroutines.

• print $var - Evaluate a variable.

• info $type [regex] - Outputs information about the symbol table. An optional regex filters the list. Example info funcs unicode. Valid types are:

  • args - Prints the name and value of all arguments to the current function
  • funcs - Prings the name of all defined functions
  • locals - Prints the name and value of all local variables in the current context
  • sources - Prings the path of all source files
  • vars - Prints the name and value of all package variables in the app. Any variable that is not local or arg is considered a package variables

• exit - Exit the debugger.

Upcoming features

• In-scope variable setting
• Support for OS X
• Editor integration

License

MIT