Client: Don't panic on eviction

[sentientwaffle]

Language clients no longer panic when they receive an eviction message from the cluster.
Instead, any in-flight (or future) packets fail with PacketStatus.ClientEvicted.

Note that for simplicity the client eviction reason is not made available.

Rather than plumbing the eviction reason around (e.g. by turning PacketStatus into a union(enum)?), we can use logging to inform the operator about the details.

[batiati]

Note that for simplicity the client eviction reason is not made available.

Rather than plumbing the eviction reason around (e.g. by turning PacketStatus into a union(enum)?), we can use #2472 to inform the operator about the details.

Alternatively, we could select a few eviction reasons that are worth exposing to the client and represent them as distinguished PacketStatus errors.
For example:

const PacketError = error{
    TooMuchData,
    ClientShutdown,
    ClientReleaseIncompatible, // Evicted due to incompatible releases, should upgrade.
    ClientEvicted, // The server kicked us, we may try connecting again.
    InvalidOperation,
    InvalidDataSize,
};

[batiati]

Note to self: RequestException does indicate user-facing exceptions such as TooMuchData, ClientShutdown and now ClientEvicted, on the contrary to what is stated in the comment "thrown when the internal invariants of the underlying native library are violated, which is expected to never happen."

This documentation must be updated, but maybe this exception should be a checked exception explicitly handled by the user, reverting 5c93c3c.

tigerbeetle/src/clients/java/src/main/java/com/tigerbeetle/RequestException.java

Lines 3 to 9 in 5e9a0a2

	/**
	* RequestException is thrown when the internal invariants of the underlying native library are
	* violated, which is expected to never happen. If tis exception is thrown, then either there is a
	* programming error in the tigerbeetle-java library itself, or there is a version mismatch between
	* the java code and the underlying native library.
	*/
	public final class RequestException extends RuntimeException {

[batiati]

❤️

[sentientwaffle]

Alternatively, we could select a few eviction reasons that are worth exposing to the client and represent them as distinguished PacketStatus errors.

Great suggestion! I will implement that in a follow-up PR, so that this PR is included in monday's release.

[sentientwaffle]

Looks like this PR introduced a flake to the integration tests, so it won't be in monday's release after all. I'll investigate after the weekend!