a4dfd2614f
This adds a new `org.osbuild.bind` mount feature to the osbuild
mount modules. This allows to (r)bind mount parts of another mount
into the tree (or replace the default tree for a stage entirely).
The use case is the `bootc install to-filesystem` where we get
a populated disk and need to do customizations directly there
without going through an intermediate tree.
Note that right now only "--rbind" is supported and used but
we could trivially change that to become an option in either
direction. Given that the main use-case right now is to be
paried with `org.osbuild.ostree.deployment` and here the
`rbind` is crucial I would leave that the default.
Here is an example what this looks like:
```json
{
"type": "org.osbuild.users",
"options": {
"users": {
"alice": {
"home": "/home/alice",
"groups": [
"wheel"
],
"password": "$6$NV3P7UzUqP3xb1ML$3qnHpWs037VRTaOc.kirQ4.RwNz4gu9dkhAhpBYVCkHw8CMhpBKnegyyqw0QfURowarZnRnQi.jo4JEzIOvPO/",
"key": "ssh-rsa AAA ... user@email.com"
}
}
},
"devices": {
"disk": {
"type": "org.osbuild.loopback",
"options": {
"filename": "disk.raw",
"partscan": true
}
}
},
"mounts": [
{
"name": "part4",
"type": "org.osbuild.ext4",
"source": "disk",
"target": "/",
"partition": 4
},
...
{
"name": "ostree.deployment",
"type": "org.osbuild.ostree.deployment",
"options": {
"source": "mount",
"deployment": {
"default": true
}
}
},
{
"name": "bind",
"type": "org.osbuild.bind",
"target": "tree://",
"options": {
"source": "mount://"
}
}
]
},
```
86 lines
2.1 KiB
Python
Executable file
86 lines
2.1 KiB
Python
Executable file
#!/usr/bin/python3
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"""
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Bind mount service
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Can (r)bind mount mounts to the tree.
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"""
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import os.path
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import subprocess
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import sys
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from typing import Dict
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from urllib.parse import urlparse
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from osbuild import mounts
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SCHEMA_2 = """
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"additionalProperties": false,
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"required": ["name", "type", "target"],
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"properties": {
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"name": { "type": "string" },
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"type": { "type": "string" },
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"target": {
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"type": "string",
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"pattern": "^tree://"
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},
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"options": {
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"required": ["source"],
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"source": {
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"type": "string",
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"pattern": "^mount://"
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}
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}
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}
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"""
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def parse_location(location, tree, mountroot: str) -> str:
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# we cannot use "osutil.util.parsing" here because it is too
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# tightly coupled with how arguments for stages are passed
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url = urlparse(location)
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path = url.netloc
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if url.scheme == "tree":
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return os.path.join(tree, path.rstrip("/"))
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if url.scheme == "mount":
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return os.path.join(mountroot, path.rstrip("/"))
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raise ValueError(f"unsupported schema {url.scheme} for {location}")
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class BindMount(mounts.MountService):
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def __init__(self, args):
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super().__init__(args)
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self.mountpoint = ""
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def mount(self, args: Dict):
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tree = args["tree"]
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mountroot = args["root"]
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target = args["target"]
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# we cannot use args["sources"] here because the osbuild code makes
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# many assumptions about that it must link back to a "Device" so
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# we follow the pattern from org.osbuild.ostree.deployment here
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# and put it into "options"
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options = args["options"]
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source = parse_location(options.get("source"), tree, mountroot)
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self.mountpoint = parse_location(target, tree, mountroot)
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subprocess.run([
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"mount",
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"--rbind", source, self.mountpoint,
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], check=True)
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def umount(self):
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if self.mountpoint:
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subprocess.run(["umount", "-R", "-v", self.mountpoint], check=True)
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self.mountpoint = ""
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def sync(self):
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pass
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def main():
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service = BindMount.from_args(sys.argv[1:])
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service.main()
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if __name__ == '__main__':
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main()
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