81 lines
2.6 KiB
Plaintext
81 lines
2.6 KiB
Plaintext
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== qmp_client
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This library interfaces with a running QEMU process using the QMP protocol. It
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also works with the QEMU-KVM branch.
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To get a QMP socket for a QEMU process, use one of these command-line arguments:
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-qmp tcp:[host]:port[,server][,nowait][,nodelay]
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-qmp unix:path[,server][,nowait]
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-qmp stdio
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-qmp pipe:filename
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The QMP protocol is still evolving, and the kinds of things you can do with it
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are changing with each release. It's also currently (QEMU 0.15) impossible to
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set every option available on the command line via the QMP console. However,
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there are plans to make that possible, and this library will track the features
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available from the server as closely as possible.
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Usage example:
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QMPClient::connect_tcp("127.0.0.1", 4440) do |api|
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api.on_event('BLOCK_IO_ERROR') do |e|
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puts "Block I/O error detected: #{e.inspect}"
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end
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msg = api.sync_query("status") # Blocks until a response comes back
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puts "VM status: #{m.inspect}"
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api.command('eject', 'device' => 'ide1-cd0') {|m| puts "CDROM ejected" }
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api.query("status") {|m| puts "VM status now: #{m.inspect}" }
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msg = my_own_magic_builder_method(arg1, arg2)
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api.send_message(msg) {|m| puts m.inspect }
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result = api.sync_send_message(msg) # Blocks until a response comes back
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api.wait # Blocks until no commands or queries are outstanding.
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api.command('quit') # Specifying a callback is optional
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end
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You can also do this perfectly safely:
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stopq = Queue.new
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api_outer = nil
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Thread.new do
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QMPClient::connect_tcp("127.0.0.1", 4440) do |api_inner|
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api = api_inner
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stopq.pop
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end
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end
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sleep(0.1) while api.nil?
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# do stuff with the api object
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stopq.push(:ok)
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Or, indeed, this:
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QMPClient::connect_tcp("127.0.0.1", 4440) do |api|
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Thread.new { }.join # use the API object in here
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end
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Callbacks are run on a thread pool; if an exception is raised on one of those
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threads, the process aborts. The default thread pool size is 10. Both of these
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things will be made configurable later.
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More information about QMP can be found at the following locations:
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http://wiki.qemu.org/QMP
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http://wiki.qemu.org/Features/QAPI
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Patches to fix bugs or support new functionality are welcome. To submit a patch
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or report a bug, go to http://github.com/lupine/qmp_client - follow the usual
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fork, commit fixes and tests, send pull request procedure for github.
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The aim is to be compatible with Ruby 1.8.7 and 1.9.3 as implemented by MRI,
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Rubinius and JRuby - tests and fixes to that aim are especially welcomed.
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See LICENSE for copyright details.
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- Nick Thomas <nick@lupine.me.uk>
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