Add bazel flag for max_cas_entry size.

[amishra-u]

Description of the feature request:

As of today, the max_cas_entry_size is declared at the server side. In the event that Bazel sends a write request containing a digest larger than the specified max_cas_entry_size, the remote cache throws an 'out_of_range' error. By introducing a Bazel flag for max_cas_entry_size, it becomes possible to validate it on the client side, potentially eliminating the need for a round trip to the server. This improvement has the potential to enhance build performance.

What underlying problem are you trying to solve with this feature?

Improved build performance with remote cache.

[diegohavenstein]

@tjgq @sgowroji @Pavank1992 could you give an estimate of how much work this is? I'd be willing to help, but need to know roughly how much work it is. Sounds like passing through an argument and putting a conditional somewhere around the upload logic, but not sure if it is that simple

[tjgq]

Before we decide to add a flag: is this something that could be negotiated with the server during the initial handshake? (We already negotiate other things, like the digest hash function used by the CAS.)

[amishra-u]

@tjgq yes, remote-cache can send the max supported cas entry size on getcapablities call, this way we will not need to add any bazel flag (seems better option).
but we may need to add new property in the repsonse. https://github.com/bazelbuild/remote-apis/blob/main/build/bazel/remote/execution/v2/remote_execution.proto#L1968

[tjgq]

In that case, could you bring this up as a potential addition to the spec by filing an issue at https://github.com/bazelbuild/remote-apis?

[diegohavenstein]

Sounds like a better approach indeed

@amishra-u can you please also update the feature request here and assign it to me? (I can't edit) Thx!

[amishra-u]

@diegohavenstein same here, I don't have permission to assign the task to anyone.

[coeuvre]

@diegohavenstein I have assigned to you. Thanks!