Re: [Libguestfs] [PATCH nbdkit v2] Add the ability to write plugins in golang.

On Tue, Apr 21, 2020 at 05:07:43PM +0100, Daniel P. Berrangé wrote: > On Tue, Apr 21, 2020 at 11:44:59AM +0100, Richard W.M. Jones wrote: > > Thanks: Dan Berrangé > > > > XXX UNFINISHED: > > > > - Is using uintptr for the handle a good idea? Plugins must return > > something != 0. In other languages we would allow plugins to > > return an arbitrary object here, but this is not possible in golang > > because of lack of GC roots. > > Yeah, this is the bit that looks wierd to me when thinking about this > from a Go dev POV. You asked me on IRC whether we should have a separate > interface for a connection object, and this makes me think that we should > indeed do that. ... This is what the patch looks like with a separate connection object. It appears to work. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://people.redhat.com/~rjones/virt-df/

From a929cff8745f21df913ea3230741dc7f2a1c016e Mon Sep 17 00:00:00 2001 From: "Richard W.M. Jones" <rjones(a)redhat.com&gt; Date: Thu, 9 Apr 2020 12:45:10 +0100 Subject: [PATCH] Add the ability to write plugins in golang. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Thanks: Dan Berrangé XXX UNFINISHED: - Default can_* methods are hard to implement. Ideally we would be able to test if a user plugin implements a particular callback (eg. TestPlugin.PWrite) or else defaults to the default callback, but even with reflection I don't think this is possible in golang. [Discussed on IRC: We decided the only option was to go for nbdkit-sh-plugin style can_* methods] - Write wrappers etc for all the other methods. - Write documentation. --- plugins/golang/nbdkit-golang-plugin.pod | 34 +++ configure.ac | 32 +++ plugins/golang/Makefile.am | 80 ++++++ .../src/libguestfs.org/nbdkit/wrappers.h | 41 +++ plugins/golang/config-test.go | 38 +++ .../src/libguestfs.org/nbdkit/nbdkit.go | 270 ++++++++++++++++++ .../golang/src/libguestfs.org/nbdkit/utils.go | 75 +++++ .../src/libguestfs.org/nbdkit/wrappers.go | 102 +++++++ plugins/golang/test/run-test.sh | 42 +++ plugins/golang/test/test.go | 119 ++++++++ .gitignore | 2 + README | 4 + 12 files changed, 839 insertions(+) create mode 100644 plugins/golang/nbdkit-golang-plugin.pod create mode 100644 plugins/golang/Makefile.am create mode 100644 plugins/golang/src/libguestfs.org/nbdkit/wrappers.h create mode 100644 plugins/golang/config-test.go create mode 100644 plugins/golang/src/libguestfs.org/nbdkit/nbdkit.go create mode 100644 plugins/golang/src/libguestfs.org/nbdkit/utils.go create mode 100644 plugins/golang/src/libguestfs.org/nbdkit/wrappers.go create mode 100755 plugins/golang/test/run-test.sh create mode 100644 plugins/golang/test/test.go