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88 lines
2.4 KiB
Markdown
88 lines
2.4 KiB
Markdown
# RFC-0005 Extend supported list of image automation marker reference attributes
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**Status:** provisional
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**Creation date:** 2021-12-16
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**Last update:** 2021-12-16
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## Summary
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Flux should allow referencing more metadata in the image automation Setters strategy.
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## Motivation
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Some automation or observability tools can use label to identify better a
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kubernetes object. It can be linked to a version, a date, a code
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origin... For multiple reason, the image tag can reflect poorly this
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data. An example can be given by the image reflector controller which
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can extract a part of the tag and use it to sort and select the correct one.
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### Goals
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This RFC aims to describe
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- A way to extract such additional attributes from the image tag.
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- Use those new attributes to update the kubernetes object.
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### Non-Goals
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This RFC will focus on Image Automation Controller and Image Reflector Controller.
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It is a non goal to keep in sync the attributes if the kubernetes object is
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updated manually.
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## Proposal
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### User Stories
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As a user, I can update the filter pattern on the image policy object to
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capture additional data.
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Then, I can reference the name of the captured group in the comment of a
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kubernetes object so that the attribute linked to this comment can be updated.
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### Alternatives
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An alternative would be to build a mutation web hook which would be able to
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filter all object and interact with them directly.
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It would be more generic, more customizable and safer (fix the manual update use case)
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to create such mutation web hook, but will be heavier to build.
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(new kubernetes object, new controller)
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This raise the question on should this feature to be included in flux or not.
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## Design Details
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Simple update on the image automation controller should be enough. Today a
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filter in the image policy is like:
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```yaml
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extract: $ts
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pattern: ^pr-(?P<pr>.*)-(?P<ts>\d*)-(?P<sha1>.*)$
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```
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It is possible to modify the image automation to take comment like:
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```yaml
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# {"$imagepolicy": "{namespace}:{imagepolicy}:{attributes}"
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```
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with `attributes` a name of a capture group on the pattern.
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From previous pattern example, accepted attributes will be:
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- pr
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- ts
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- sha1
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If a user try to use an attribute name like `tag` or `name` which is
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already defined by flux core, then the original meaning will still be kept :
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- tag: the full tag string
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- name: the image name
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## Implementation History
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_not implemented yet_ |