[Cases] Registering file attachment type

[jonathan-buttner]

This PR registers the file attachment type .files within the cases attachment framework.

Notable changes:

• Attachment framework accepts an optional validation function for use when a request is received for that attachment type, this allows validating that the file metadata is correct
• Refactored the logic for enforcing that only 1000 alerts can be attached to a case and 100 files

Issue: #151933

cUrl request to create file attachments

curl --location --request POST 'http://elastic:changeme@localhost:5601/internal/cases/<case id>/attachments/_bulk_create' \
--header 'kbn-xsrf: hello' \
--header 'Content-Type: application/json' \
--data-raw '[
    {
        "type": "externalReference",
        "externalReferenceStorage": {
            "type": "savedObject",
            "soType": "file"
        },
        "externalReferenceId": "my-id",
        "externalReferenceAttachmentTypeId": ".files",
        "externalReferenceMetadata": {
            "file": {
                "name": "test_file",
                "extension": "png",
                "mimeType": "image/png",
                "createdAt": "2023-02-27T20:26:54.345Z"
            }
        },
        "owner": "cases"
    },
    {
        "type": "externalReference",
        "externalReferenceStorage": {
            "type": "savedObject",
            "soType": "file"
        },
        "externalReferenceId": "my-id",
        "externalReferenceAttachmentTypeId": ".files",
        "externalReferenceMetadata": {
            "file": {
                "name": "test_file",
                "extension": "png",
                "mimeType": "image/png",
                "createdAt": "2023-02-27T20:26:54.345Z"
            }
        },
        "owner": "cases"
    },
        {
        "type": "externalReference",
        "externalReferenceStorage": {
            "type": "savedObject",
            "soType": "file"
        },
        "externalReferenceId": "my-id",
        "externalReferenceAttachmentTypeId": ".files",
        "externalReferenceMetadata": {
            "file": {
                "name": "test_file",
                "extension": "jpeg",
                "mimeType": "image/jpeg",
                "createdAt": "2023-02-27T20:26:54.345Z"
            }
        },
        "owner": "cases"
    }
]
'

[elasticmachine]

Pinging @elastic/response-ops (Team:ResponseOps)

[elasticmachine]

Pinging @elastic/response-ops-cases (Feature:Cases)

[adcoelho]

If this is an "Internal attachment type" that should always exist maybe it would make more sense to register it when externalReferenceAttachmentTypeRegistry is initialized and not when the cases plugin is set up?

[cnasikas]

The externalReferenceAttachmentTypeRegistry should not be considered as a singleton. It can be instantiated in various places where a clean state is needed and can lead to bugs if not. It will also make the testing much harder if the state of the class contains our internal attachments.

[jonathan-buttner]

I think I'm open to either keeping the registration in the plugin or making it a part of the ExternalReferenceAttachmentTypeRegistry. If it makes testing easier to do registration in the plugin that's fine with me.

[adcoelho]

It will also make the testing much harder if the state of the class contains our internal attachments.

But if I understand it correctly the class is "ours" so wherever it is used it will need those internal attachments.

My reasoning was that it is why more error-prone to have to remember to register internal types every time we instantiate it. External ones though are fine because those are the responsibility of the "instantiator".

[cnasikas]

My reasoning was that it is why more error-prone to have to remember to register internal types every time we instantiate it

I see what you mean. This should never happen. This class is instantiated only once in the setup lifecycle method of the cases plugin. The same instance is passed down to the cases code and lives throughout the whole lifecycle of the cases plugin (This can be a counterargument to my main point 🙂). If you need a new instance of the class you probably need it for testing or to do something else unrelated to the internal attachments.

I see the cases plugin as an external consumer of the externalReferenceAttachmentTypeRegistry and not as an internal consumer. By registering data in the constructor of the externalReferenceAttachmentTypeRegistry you tight couple the data with the logic of the class (representation). The class is now aware of the data which are implementation detail. The class has more concerns than it should have.

[adcoelho]

lgtm, just some minor comments 👍

[kibana-ci]

💚 Build Succeeded

• Buildkite Build
• Commit: ca8dbdb

Metrics [docs]

Module Count

Fewer modules leads to a faster build time

id	before	after	diff
cases	564	565	+1

Page load bundle

Size of the bundles that are downloaded on every page load. Target size is below 100kb

id	before	after	diff
cases	133.2KB	133.3KB	+107.0B

Unknown metric groups

ESLint disabled line counts

id	before	after	diff
securitySolution	428	430	+2

Total ESLint disabled count

id	before	after	diff
securitySolution	506	508	+2

History

• 💚 Build #111351 succeeded 5fedc02
• 💚 Build #111227 succeeded cbb58f4

To update your PR or re-run it, just comment with:
@elasticmachine merge upstream

[cnasikas]

Code LGMT! Tested without issues 🚀