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path: root/pkg/hooks/monitor.go
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* Improved hooks monitoringsamc242019-07-25
| | | | | | | | | | | | | ...to work for specific edge cases with a simpler solution. Re-reads hooks directories after any changes are detected by the watchers. Added monitoring test for adding a different invalid hook to primary directory. Some issues with prior code: - ReadDir would stop when it encounters an invalid hook, rather than registering an error but continuing to read the valid hook. - Wouldn’t account for Rename and Chmod events. - After doing a mv of the hooks file instead of rm, it would still think the hooks file is in the directory, but it has been moved to another location. - If a hook file was renamed, it would register the renamed file as a separate hook and not delete the original, so it would then execute the hook twice - once for the renamed file, and once for the original name which it did not delete. Signed-off-by: samc24 <sam.chaturvedi24@gmail.com>
* hooks: Fix monitoring of multiple directoriesW. Trevor King2018-05-17
| | | | | | | | | | | | | | | | | | | | | | | | | | This isn't an issue with podman, which will only ever use one directory. But CRI-O generally uses two directories, and we want to make sure that changes to the fallback directory are not clobbering hooks configured in the override directory. More background in [1]. I've split the handling into a single-directory block and a multiple-directory block so we don't waste time polling the filesystem for single-directory removals. I'm using the single-directory block for the the zero-directory case as well. Managers with zero directories should not be receiving fsnotify events, so I don't think it really matters which block handles them. If we want to handle this case robustly (because we're concerned about something in the hook package adjusted the private .directories property on the fly?), then we'll probably want to add an explicit zero-directory block in future work. [1]: https://github.com/kubernetes-incubator/cri-o/pull/1470 Signed-off-by: W. Trevor King <wking@tremily.us> Closes: #757 Approved by: rhatdan
* pkg/hooks: Version the hook structure and add 1.0.0 hooksW. Trevor King2018-05-11
This shifts the matching logic out of libpod/container_internal and into the hook package, where we can reuse it after vendoring into CRI-O. It also adds unit tests with almost-complete coverage. Now libpod is even more isolated from the hook internals, which makes it fairly straightforward to bump the hook config file to 1.0.0. I've dubbed the old format 0.1.0, although it doesn't specify an explicit version. Motivation for some of my changes with 1.0.0: * Add an explicit version field. This will make any future JSON structure migrations more straightforward by avoiding the need for version-guessing heuristics. * Collect the matching properties in a new When sub-structure. This makes the root Hook structure easier to understand, because you don't have to read over all the matching properties when wrapping your head around Hook. * Replace the old 'hook' and 'arguments' with a direct embedding of the runtime-spec's hook structure. This provides access to additional upstream properties (args[0], env, and timeout) and avoids the complication of a CRI-O-specific analog structure. * Add a 'when.always' property. You can usually accomplish this effect in another way (e.g. when.commands = [".*"]), but having a boolean explicitly for this use-case makes for easier reading and writing. * Replace the previous annotations array with an annotations map. The 0.1.0 approach matched only the values regardless of key, and that seems unreliable. * Replace 'cmds' with 'when.commands', because while there are a few ways to abbreviate "commands", there's only one way to write it out in full ;). This gives folks one less thing to remember when writing hook JSON. * Replace the old "inject if any specified condition matches" with "inject if all specified conditions match". This allows for more precise targeting. Users that need more generous targeting can recover the previous behavior by creating a separate 1.0.0 hook file for each specified 0.1.0 condition. I've added doc-compat support for the various pluralizations of the 0.1.0 properties. Previously, the docs and code were not in agreement. More on this particular facet in [1]. I've updated the docs to point out that the annotations being matched are the OCI config annotations. This differs from CRI-O, where the annotations used are the Kubernetes-supplied annotations [2,3]. For example, io.kubernetes.cri-o.Volumes [4] is part of CRI-O's runtime config annotations [5], but not part of the Kubernetes-supplied annotations CRI-O uses for matching hooks. The Monitor method supports the CRI-O use-case [6]. podman doesn't need it directly, but CRI-O will need it when we vendor this package there. I've used nvidia-container-runtime-hook for the annotation examples because Dan mentioned the Nvidia folks as the motivation behind annotation matching. The environment variables are documented in [7]. The 0.1.0 hook config, which does not allow for environment variables, only works because runc currently leaks the host environment into the hooks [8]. I haven't been able to find documentation for their usual annotation trigger or hook-install path, so I'm just guessing there. [1]: https://github.com/kubernetes-incubator/cri-o/pull/1235 [2]: https://github.com/kubernetes-incubator/cri-o/blob/v1.10.0/server/container_create.go#L760 [3]: https://github.com/kubernetes-incubator/cri-o/blob/v1.10.0/server/container_create.go#L772 [4]: https://github.com/kubernetes-incubator/cri-o/blob/v1.10.0/pkg/annotations/annotations.go#L97-L98 [5]: https://github.com/kubernetes-incubator/cri-o/blob/v1.10.0/server/container_create.go#L830-L834 [6]: https://github.com/kubernetes-incubator/cri-o/pull/1345/ [7]: https://github.com/NVIDIA/nvidia-container-runtime/tree/v1.3.0-1#environment-variables-oci-spec [8]: https://github.com/opencontainers/runc/pull/1738 Signed-off-by: W. Trevor King <wking@tremily.us> Closes: #686 Approved by: mheon