The Remap parse_timestamp function format argument should be optional

[binarylogic]

I think this is already implemented in the to_timestamp function. To make timestamp parsing easier, we should do what we currently do in our legacy types conversion code:

https://github.com/timberio/vector/blob/2ab17c8ac514211d5579d16821b5e47c050c745b/src/types.rs#L205-L228

That is, automatically detect and parse common formats.

[JeanMertz]

If we do this, there isn't much that separates to_timestamp from parse_timestamp any more. Should we consolidate the two?

[binarylogic]

Yes, I think so, although to_timestamp handles integers.

[JeanMertz]

If we'd go with vectordotdev/vrl#145, I'd personally favour:

• to_timestamp(.foo, default = "2020/10/21") (together with to_string, etc)
• timestamp::parse(.foo, format = "%s") (for this one I'd make the format optional, and remove the default parameter)

[binarylogic]

Actually, I'm going to close this. I think the current behavior is correct:

• to_timestamp is automatic, intended for simple conversions.
• parse_timestamp is specific to a custom format.