metadata-check: support metadata search path

[oliver-sanders]

The Problem

The rose metadata-check command supports specifying the metadata directory.

However, it does not support configuring the metadata search path as other Rose commands do, using the -M option or the ROSE_META_PATH environment variable.

Example

.
|-- here
|   |-- grav
|   |   `-- rose-meta.conf
|   `-- mesh
|       `-- rose-meta.conf
`-- some-meta
    `-- rose-meta.conf

# ./some-meta/rose-meta.conf
[env=FOO]

# ./here/grav/rose-meta.conf
import=some-meta

# ./here/mesh/rose-meta.conf
[env=TYPE]

Running the metadata-check command on the mesh config works fine:

$ rose metadata-check -v -C ./here/mesh
[INFO] Configurations OK

However, the grav config fails with a cryptic error:

$ rose metadata-check -v -C ./here/grav
/var/tmp/tmp.80X2llkvnr/here/grav: not a configuration metadata directory.

Which is actually masking an OS error:

FileNotFoundError: [Errno 2] No such file or directory: '/var/tmp/tmp.80X2llkvnr/here/some-meta/rose-meta.conf'

Which we cannot circumnavigate, as we cannot configure the metadata search path to make Rose look up one directory.

TODO:

• Make the metadata search path configurable as for other Rose commands.
• Improve the error message for "import not found" use cases.

[oliver-sanders]

The example may behave differently with/without the ./ after the -C?