Add option flag to filter the modified files

[bewie]

Hi,
I use a mono-repo with a lot of non related terraform files or some projects that I don't want to plan/apply from atlantis.
So I want to filter on specific path from my repository to select only the sub-directory that I want to plan/apply.
To do that I added an option flag to filter the modifications on a specific path.

[codecov]

Codecov Report

Merging #151 into master will increase coverage by 0.03%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #151      +/-   ##
==========================================
+ Coverage   64.14%   64.18%   +0.03%     
==========================================
  Files          41       41              
  Lines        1969     1971       +2     
==========================================
+ Hits         1263     1265       +2     
  Misses        641      641              
  Partials       65       65

Impacted Files	Coverage Δ
cmd/server.go	79.36% <ø> (ø)	⬆️
server/server.go	64.24% <100%> (+0.18%)	⬆️
server/events/project_finder.go	100% <100%> (ø)	⬆️
server/events/plan_executor.go	89.47% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 9e5f57a...dae05b3. Read the comment docs.

[lkysow]

Hi Laurent, first of all, thank you for your contribution. I appreciate the care you took and how you also updated the tests. I think that I may be close to solving your problem in another way though.

I'm very close to a new release of Atlantis that will affect you in two ways:

1. running atlantis plan will no longer cause Atlantis to attempt to figure out which directories to run plan in. It will default to just running plan in the root of the repo. This is because...
2. atlantis will now automatically run plan when you open a new pull request or new commits are pushed to an existing pull request. This would still cause you issues which is why we support a new config file that allows you to configure which paths to run plan in depending on which files are modified.

For example given the following structure:

/
  /tf-project
    main.tf,
  /outscope
    main.tf
  /modules
    /my-module

You could set up an atlantis.yaml file in the repo root as follows:

version: 2
projects:
- dir: tf-project
  autoplan:
    when_modified: ["*.tf", "../modules/my-module/*.tf"]  

The when_modified key supports the .dockerignore syntax (except for matching, not ignoring).

To apply you would run atlantis apply -d tf-project OR, you could name the project:

...
- dir: tf-project
  name: tf-project

And run atlantis apply -p tf-project.

Now when commits come to tf-project and outscope, only tf-project will be planned. The downside of this for you is that you'll have to list all of your directories that you'd like planned. Would that be a real pain for you? I'm open to feedback on this design. I want to move Atlantis to per-repo configuration rather than using global flags that apply to all repos because many users want different settings per repo.

[bewie]

Hi Luke, thanks for your reply.

The automatically plan on PR will be awesome!
I have to try the atlantis.yaml configuration per directory if it match with my cases. Yes it could be annoying to list all directories, actually I have 39 projects under the path that I want to watch... But I can deal with it, it's not moving a lot and I have to config it only once.
Do you know when I the new release will be available? :-)

[lkysow]

I should have an alpha release out by the end of the week. Yeah listing 39 directories isn't great but for now I think you'll have to. I'm happy to make the config less explicit but I want to see some more use cases so if I change the schema it works for everyone.

I'm going to close this for now since the new release should achieve what you're looking for.

[lkysow]

@bewie I think you already saw this but 0.4 was released yesterday.