Use user specified directory for resolving file path

[VinozzZ]

What does this change

Currently, porter assumes current working directory is pwd() even if users have specified a directory through --dir.
Therefore using --file flag requires users to always provide the absolute file path to porter manifest file, or porter sill use pwd() as the root directory when a relative path is provided.

example:

$ pwd
$ /home/test
$ porter build --file hello/porter.yaml --dir /home/test/example

The resolved porter manifest path would be /home/test/hello/porter.yaml

This PR changes the behavior to use the directory specified by --dir as the root directory when resolving relative path provided by --file .

example:

$ pwd
$ /home/test
$ porter build --file hello/porter.yaml --dir /home/test/example

The resolved porter manifest path would be /home/test/example/hello/porter.yaml

What issue does it fix

Closes #1447

Notes for the reviewer

Checklist

• Did you write tests?
• Did you write documentation?
• Did you change porter.yaml or a storage document record? Update the corresponding schema file.
• If this is your first pull request, please add your name to the bottom of our Contributors list. Thank you for making Porter better! 🙇‍♀️

Reviewer Checklist

• Comment with /azp run test-porter-release if a magefile or build script was modified
• Comment with /azp run porter-integration if it's a non-trivial PR

[carolynvs]

@VinozzZ When you are ready for a review, just move it out of draft 👍

[carolynvs]

This is looking good! I just have some small suggestions

[carolynvs]

I think we can simplify this a bit since the build context directory defaults to the working directory.

Suggested change

	"Path to the Porter manifest. When build context directory is specified, relative path will be resolved using the build context directory as the root directory. Defaults to `porter.yaml` in the current directory.")
	"Path to the Porter manifest. The path is relative to the build context directory. Defaults to porter.yaml in the current directory.")

[VinozzZ]

I wanted to make sure that users understand that if a absolute path is passed in, then it won't be relative to the build context directory. How about we say
`When a relative path is provided, the path is relative to the build context directory"

[carolynvs]

The build context directory (--dir) defaults to the current directory. So when you say "relatative to the build context directory" I think that covers both cases, no?

I just double checked and --dir doesn't say "Defaults to the current directory". How about we add that (it should have been included so that's an oversight)? I'm trying to avoid complex explanations, and explaining the --dir flag on the helptext for the --file flag.

[carolynvs]

Isn't o.Dir always set in the if statement above? I think we can simplify this to the following

Suggested change

	if o.Dir != "" && !filepath.IsAbs(o.File) {
	o.File = cxt.FileSystem.Abs(filepath.Join(o.Dir, o.File))
	if !filepath.IsAbs(o.File) {
	o.File = cxt.FileSystem.Abs(filepath.Join(o.Dir, o.File))

[VinozzZ]

I thought the o.Dir is only resolved if it's not empty in the if statement above?

[carolynvs]

Ah okay thanks I thought that if it was empty, we were setting it to the absolute path of the current working directory. If we did that then we wouldn't need a bunch of defensive checks later in the code since we know it was initialized properly. What do you think?

[carolynvs]

Again, isn't o.Dir always set?

[carolynvs]

Suggested change

	if err != nil {
	return errors.Wrap(err, "could not check if porter manifest exists in current directory")
	}
	if err != nil {
	return errors.Wrapf(err, "could not find a porter manifest at %s", defaultpath)
	}

[carolynvs]

Sorry about all the nits. I'm just trying to reduce the "if this, then this, otherwise that" aspect of this feature that was baked into the code. It adds unnecessary complexity for us and the user, and I'm hoping we can make this easier for everyone.

[VinozzZ]

Sorry about all the nits. I'm just trying to reduce the "if this, then this, otherwise that" aspect of this feature that was baked into the code. It adds unnecessary complexity for us and the user, and I'm hoping we can make this easier for everyone.

No worries at all! I would love to make the helper message more clear

[carolynvs]

Thanks for your patience while we hammered out how this should work. This looks great and I think will be easier for people to use. 👍