When performing substitutions, there are occasions when the source value
does not exactly match the format required by the destination document
(e.g. the values.yaml structure of an Armada chart).
This change provides the ability extract a substring of the source
value, and substitute that into the destination document.
Two optional fields are added to `src` under `metadata.substitutions`:
* `pattern`: a regular expression, with optional capture groups
* `match_group`: the number of the desired capture group
The canonical use case is a chart that requires an image with the repo
name and tag in separate fields, while the substitution source has the
full image path as a single value.
For example, assuming that the source document "software-versions" has:
data:
images:
hello: docker.io/library/hello-world:latest
Then the following set of substitutions would put the repo and tag in
the applicable values in the destination document:
metadata:
substitutions:
- src:
schema: pegleg/SoftwareVersions/v1
name: software-versions
path: .images.hello
pattern: '^(.*):(.*)'
match_group: 1
dest:
path: .values.images.hello.repo
- src:
schema: pegleg/SoftwareVersions/v1
name: software-versions
path: .images.hello
pattern: '^(.*):(.*)'
match_group: 2
dest:
path: .values.images.hello.tag
data:
values:
images:
hello:
repo: # docker.io/library/hello-world
tag: # latest
Change-Id: I2fcb0d2b8e2fe3d85479ac2bad0b7b90f434eb77
5cd799cc5d