pycriu: making images_dir_fd optional

[herheliuk]

Since images_dir_fd is a required filed in rpc.proto we must
explicitly pass it into opts in order to use images_dir.

Co-authored-by: Andrei Vagin [email protected]
Signed-off-by: Andrii Herheliuk [email protected]

[herheliuk]

haven't tested lib/c, there might be the same issue

[herheliuk]

current example of images_dir usage:

from pycriu import criu as pycriu_criu

criu = pycriu_criu()

criu.opts.images_dir_fd = -1
criu.opts.images_dir = dumps_dir
criu.opts.pid = int(input('pid: '))
criu.opts.shell_job = True
criu.dump()

if we don't set criu.opts.images_dir_fd to -1:

google.protobuf.message.EncodeError: Message criu_req is missing required fields: opts.images_dir_fd

[avagin]

it might be better to do something like that:

diff --git a/lib/pycriu/criu.py b/lib/pycriu/criu.py
index 5bd7ffecd..a496756d5 100644
--- a/lib/pycriu/criu.py
+++ b/lib/pycriu/criu.py
@@ -204,6 +204,9 @@ class criu:
     def __init__(self):
         self.use_binary('criu')
         self.opts = rpc.criu_opts()
+        # write a comment here why it is needed.
+        if self.opts.HasField("image_dir_fd"):
+          self.opts.images_dir_fd = -1
         self.sk = None
 
     def use_sk(self, sk_name):

[herheliuk]

Actually we can't do that, because we need to explicitly set images_dir_fd in req.opts not self.opts

P.S. CopyFrom(self.opts) doesn't work either, since it's a required field we need to pass it explicitly.

[herheliuk]

Oh wait, my bad

[herheliuk]

@avagin That's actually much better, thank you

[herheliuk]

#2789 Copies this PR.