Set correct path for uploaded file in sim config

[mattdailis]

Closes #1046

Description

Aerie allows the mission model to declare a sim config parameter of type Path. The Aerie UI displays this parameter type with a Browse button that allows the user to upload a file.

The aerie gateway changes the names of uploaded files to ensure uniqueness (e.g. if I upload banananation.jar multiple times, I do not typically want it to overwrite other files with the same name).

The Aerie UI sets the name of the Path parameter in the sim config to the name of the original file, not the modified name generated by the gateway. This path also omits the absolute path prefix of the location at which the aerie_file_store is mounted in the aerie_merlin and aerie_merlin_worker_* containers.

As a consequence of the above, there is no way for the mission model to take the provided Path parameter and resolve it to the correct file location in the file system. This negates the utility of using Path parameters in a sim config.

Problem Statement

A mission model should be able to use a sim config parameter of type Path to find a file that the planner uploaded using the UI's sim config form.

Approach

The most targeted fix (i.e. a fix that only touches one repo) is to update the UI to fill in the Path parameter with the correct absolute path to the uploaded file. It can do this with the following steps:

1. After uploading the files, keep track of the uploaded file ids
2. Issue a follow-up query to get the generated names of those files
3. Traverse the sim config, finding all Path parameters and replace them with a hard-coded prefix followed by the generated filename, e.g:

/usr/src/app/merlin_file_store/my-file-name-1702092509728-CMvkjzriKBQvuc.json

A drawback of this approach is that it hard-codes the mount point /usr/src/app/merlin_file_store/. Perhaps an easy step we could take would be to set this in an environment variable.

• TODO set /usr/src/app/merlin_file_store/ in an environment variable

Verification

As a manual test, upload a banananation mission model, and upload a text file to the initialDataPath sim config parameter. Run a simulation, and observe the /data/line_count resource - it should correctly report the number of lines in your uploaded file.

Future work

• The fact that the UI needs to know the mount point of the merlin_file_store feels a bit strange - in theory, the simulation context should be able to add that prefix to every provided path parameter.
• There is no way to choose an existing file, or even see the existing set of uploaded files. It may be worth looking into some UI to manage uploaded files

[duranb]

Looks good for the most part other than one comment that I left!

[duranb]

💯 🥇 🚀