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