DOP-4248: Create action that uploads directory content to S3

[seungpark]

This PR exposes a github action that uploads a directory (and its contents) to a specified AWS S3 bucket (and path).

Front end workflow that uses this action is found here

Test Deploy of this action

[seungpark]

this was changed in order to work with this mime package for node

[mmeigs]

Looks great. I just put annoying comments 🤭

[mmeigs]

nit: I wonder if this nullish coalescer is necessary because it would have thrown an error?

[branberry]

I think this is a limitation of TypeScript where it doesn't know if process.env[requiredVar] is defined or not even if we check because requiredVar is a variable we use to index it.

[branberry]

Here's a way that this can be done without running into TS errors. There are a few more moving parts, but this should make TypeScript happy. I added some explanations, but if I can clarify something more let me know!!

const REQUIRED_ENV_VARS = [
  'AWS_BUCKET',
  'PROJECT',
  'SOURCE_DIR',
  'DESTINATION_DIR',
  'COMMIT_HASH',
  'GITHUB_WORKSPACE',
] as const;

// translates the array of values in REQUIRED_ENV_VARS into a literal type i.e. RequiredVar = 'AWS_BUCKET' | 'PROJECT' ....
type RequiredVar = (typeof REQUIRED_ENV_VARS)[number];

// We can then use this literal type to create an object definition. Have to use a type here instead of an interface
// as interfaces don't support mapped types very well :/
// This boils down to the same intreface, but with the added benefit of being able to assign these string values to the object in
// the getEnvVars function. If this is not done, TypeScript sees a string versus a key within the `envParams` type. Because of this,
// an error will occur if you try assigning a value to the envParams object.
type envParams = {
  [V in RequiredVar]: string;
};

function getEnvVars(): envParams {
  const res: Partial<envParams> = {};
  for (const requiredVar of REQUIRED_ENV_VARS) {
    const envVar = process.env[requiredVar];
    if (!envVar) {
      const errMsg = `Required env variable missing: ${requiredVar}`;
      core.error(errMsg);
      throw new Error(errMsg);
    }
    res[requiredVar] = envVar;
  }
  return res as envParams;
}

[mmeigs]

omg grosssss typescript!! 😭 @branberry you right, you always right!

[branberry]

Lol, I wish I was always right... I've just had to do this so many times already hahaha. I've been wallowing in the murky TypeScript underbelly for far too long...

[seungpark]

this part was throwing an error so i updated it to be a type Record<RequiredVar, string>;

type envParams = {
  [var in RequiredVar]: string;
};

[branberry]

Ah, the issue is that var is a JavaScript keyword.. If you use something like V instead of var the error goes away.

But, I prefer the Record as that is more readable

[mmeigs]

Could this type be Partial<envParams>?

[seungpark]

done!

[mmeigs]

nit of nits: I believe the convention is to capitalize interface names

[seungpark]

done!

[mmeigs]

Nice