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* 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
* hooks/docs: Add oci-hooks.5 and per-package man page buildingW. Trevor King2018-05-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This allows us to reference the hooks docs from podman(1) in a way that will survive system installation. The downside is that the GitHub rendered pages become less usable, now that we can no longer embed links as freely as we could before. I've followed the "Sections within a manual page" suggestions from [1]. locale(7) is [2], which is Linux-specific. Even section numbering is platform-dependent [3], so it's unlikely that these external man references are particularly portable. Platform packagers can adjust our local references to match their target system, but that leaves the GitHub rendering in an awkward place. For now, I think a Linux-centric GitHub rendering without clickable links may be the best we can do without moving away from go-md2man. As far as I can tell, there's not a nice way to get go-md2man to wrap the links in SEE ALSO without sometimes hyphenating a URL (which makes it harder for man-page readers to copy/paste those links into their browser). I've also fixed some "extention" -> "extension" typos. [1]: http://man7.org/linux/man-pages/man7/man-pages.7.html [2]: http://man7.org/linux/man-pages/man7/locale.7.html [3]: https://en.wikipedia.org/wiki/Man_page#Manual_sections Signed-off-by: W. Trevor King <wking@tremily.us> Closes: #772 Approved by: mheon
* hooks: Add package support for extension stagesW. Trevor King2018-05-14
| | | | | | | | | | | | | We aren't consuming this yet, but these pkg/hooks changes lay the groundwork for future libpod changes to support post-exit hooks [1,2]. [1]: https://github.com/projectatomic/libpod/issues/730 [2]: https://github.com/opencontainers/runc/issues/1797 Signed-off-by: W. Trevor King <wking@tremily.us> Closes: #758 Approved by: rhatdan
* hooks: Order injection by collated JSON filenameW. Trevor King2018-05-11
| | | | | | | | | | | | | | | | | | | | | | | We also considered ordering with sort.Strings, but Matthew rejected that because it uses a byte-by-byte UTF-8 comparison [1] which would fail many language-specific conventions [2]. There's some more discussion of the localeToLanguage mapping in [3]. Currently language.Parse does not handle either 'C' or 'POSIX', returning: und, language: tag is not well-formed for both. [1]: https://github.com/projectatomic/libpod/pull/686#issuecomment-387914358 [2]: https://en.wikipedia.org/wiki/Alphabetical_order#Language-specific_conventions [3]: https://github.com/golang/go/issues/25340 Signed-off-by: W. Trevor King <wking@tremily.us> Closes: #686 Approved by: mheon
* hooks/read: Ignore IsNotExist for JSON files in ReadDirW. Trevor King2018-05-11
| | | | | | | | | | | | | | | If a .json file existed when we called ioutil.ReadDir but that file has been removed by the time we get around to calling Read on it, silently ignore the file. Iterating through all the files in the directory shouldn't take particularly long, so this is an unlikely corner case. And when it happens, silently ignoring the file gives the same outcome as you'd have gotten if the parallel remove had happened slightly earlier before the ioutil.ReadDir call. Signed-off-by: W. Trevor King <wking@tremily.us> Closes: #686 Approved by: mheon
* 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
* Add hooks support to podmanDaniel J Walsh2018-04-05
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com> Closes: #155 Approved by: mheon