pm

Processlist manager with TCP listener

Programming language: Go

License: MIT License

Tags: Utilities    

README

pm

pm is a process manager with an HTTP interface. We use it at VividCortex to inspect and manage API server programs. It replaces an internal-only project that was similar.

pm is in beta and will change rapidly. Please see the issues list for what's planned, or to suggest changes.

A Processlist is useful for inspecting and managing what's running in a program, such as an HTTP server or other server program. Processes within this program are user-defined tasks, such as HTTP requests.

Documentation

Please read the generated package documentation for both server and client.

Getting Started

Package pm is a process manager with an HTTP monitoring/control interface.

Processes or tasks are user-defined routines within a running Go program. Think of the routines handling client requests in a web server, for instance. This package is designed to keep track of them, making information available through an HTTP interface. Client tools connecting to the later can thus monitor active tasks, having access to the full status history with timing data. Also, application-specific attributes may be attached to tasks (method/URI for the web server case, for example), that will be integrated with status/timing information.

Using pm starts by opening a server port to handle requests for task information through HTTP. That goes like this (although you probably want to add error checking/handling code):

go pm.ListenAndServe(":8081")

Processes to be tracked must call Start() with a process identifier and, optionally, a set of attributes. Even though the id is arbitrary, it's up to the application to choose one not in use by any other running task. A deferred call to Done() with the same id should follow:

pm.Start(requestID, nil, map[string]interface{}{
    "host":   req.RemoteAddr,
    "method": req.Method,
    "uri":    req.RequestURI,
})
defer pm.Done(requestID)

Finally, each task can change its status as often as required with a Status() call. Status strings are completely arbitrary and never inspected by the package. Now you're all set to try something like this:

curl http://localhost:8081/procs/
curl http://localhost:8081/procs/<id>/history

where <id> stands for an actual process id in your application. You'll get JSON responses including, respectively, the set of processes currently running and the full history for your chosen id.

Tasks can also be cancelled from the HTTP interface. In order to do that, you should call the DELETE method on /procs/<id>. Given the lack of support in Go to cancel a running routine, cancellation requests are implemented in this package as panics. Please refer to the full package documentation to learn how to properly deal with this. If you're not interested in this feature, you can disable cancellation completely by running the following before you Start() any task:

pm.SetOptions(ProclistOptions{
    ForbidCancel: true
})

See package pm/client for an HTTP client implementation you can readily use from Go applications.

Contributing

We only accept pull requests for minor fixes or improvements. This includes:

• Small bug fixes
• Typos
• Documentation or comments

Please open issues to discuss new features. Pull requests for new features will be rejected, so we recommend forking the repository and making changes in your fork for your use case.

License

Copyright (c) 2013 VividCortex, licensed under the MIT license. Please see the LICENSE file for details.

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