Re: [Libguestfs] [PATCH nbdkit] plugins: python: Add imageio plugin example

On 8/6/20 5:54 PM, Nir Soffer wrote: > This is mainly for testing the new parallel python threading model, but > it also an example how to manage multiple connection from a plugin. > > I tested this with local imageio server, serving qcow2 image on local > SSD. > > diff --git a/plugins/python/examples/imageio.py b/plugins/python/examples/imageio.py > new file mode 100644 > index 00000000..e77fd2f4 > --- /dev/null > +++ b/plugins/python/examples/imageio.py > @@ -0,0 +1,167 @@ > +# Example Python plugin. > +# > +# This example can be freely used for any purpose. > +# > +# Upload and download images to oVirt with nbdkit and qemu-img. > +# > +# Install ovirt-imageio-client > +# > +# dnf copr enable nsoffer/ovirt-imageio-preview > +# dnf install ovirt-imageio-client Even after running these steps,... > +# > +# To upload or download images, you need to start an image transfer. The > +# easiest way is using oVirt image_transfer.py example: > +# > +# /usr/share/doc/python3-ovirt-enigne-sdk4/eamples/image_transfer.py \ ...I do not have a /usr/share/doc/python3-ovirt-* directory at all. Where am I supposed to get it from?

Also, I suspect you want s/enigne/engine/; s/eamples/examples/ > +# --engine-url https://my.engine \ > +# --username admin@internal \ > +# --password-file password \ > +# --cafile my.engine.pem \ > +# upload disk-uuid > +# > +# This will print the trasnfer URL for this image transfer. s/trasnfer/transfer/ > +# > +# Run this example from the build directory: > +# > +# ./nbdkit -t4 -f -v -U /tmp/nbd.sock -t4 python \ -t4 does not need to be listed twice. > +# ./plugins/python/examples/imageio.py \ > +# transfer_url=https://server:54322/images/ticket-id \ > +# connections=4 \ > +# secure=no > +# > +# Note that number of nbdkit threads and imageio connections should match. > +# > +# To upload an image run: > +# > +# qemu-img convert -f qcow2 -O raw disk.img nbd:///?socket=tmp/nbd.sock URIs containing ? should be shell-quoted (in the unlikely case that someone has an 'nbd:' subdirectory that could interfere with shell globbing). > +# > +# Downloading image is not efficient with this version, since we don't report > +# extents yet. I'll push the obvious typo fixes.

> + > +def boolify(key, value): > + v = value.lower() > + if v in ("yes", "true", "1"): > + return True > + if v in ("no", "false", 0): > + return False > + raise RuntimeError("Invalid boolean value for {}: {!r}".format(key, value)) nbdkit_parse_bool also handles 'on/off'. Should we make that function more easily available to python plugins, so you aren't having to reimplement it yourself?

> +def config_complete(): > + """ > + Called when configuration completed. missing 'is' -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3226 Virtualization: qemu.org | libvirt.org