Saga view is vague when is not able to display the saga data

[HEskandari]

There are a few reasons Saga tab would not be able to display the data for the saga. At the moment we only display 'Empty' label and it is not conclusive enough to understand what happened.

It could be either of these cases (that I know of):

• A lookup request to ServiceControl returns 404 (Not Found). This means ServiceControl somehow doesn't have the saga data anymore, potentially because it is expired (see here)
• A lookup request to ServiceControl return 204 (Non Content) when the body was not stored due to size limitations.
• Data returned via ServiceControl can not be parsed or displayed or other exceptions.

Ideally, user should be able to distinguish between the two cases. Suggesting to also revise the SC/SI documents to highlight the first case and the root cause.

[johnsimons]

@HEskandari You can also receive a 204 (No Content), that is when the message exists but we did not store the body because it was over the limit.
See https://github.com/Particular/ServiceControl/blob/0470e5ed3d651dc2fba998b09d56bd47f6bae6d1/src/ServiceControl/Operations/BodyStorage/RavenAttachments/GetBodyById.cs#L38-L51

[adamralph]

Since we are reopening closed bugs on the 1.5.8 milestone due to reverting master to 1.5.7 in #617, this issue has been moved from the 1.5.8 milestone to the Future milestone, to make a distinction.

This may be re-added to the 1.5.8 milestone if we decide to fix it before releasing 1.5.8.

[kbaley]

Triaged with @boblangley. We've re-labeled as an improvement as the functionality is not broken.