cachedb_redis: add ASK redirect handling and fix hash slot calculation#3852
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dondetir wants to merge 1 commit intoOpenSIPS:masterfrom
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cachedb_redis: add ASK redirect handling and fix hash slot calculation#3852dondetir wants to merge 1 commit intoOpenSIPS:masterfrom
dondetir wants to merge 1 commit intoOpenSIPS:masterfrom
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Add support for Redis ASK redirects during cluster resharding. When a slot is being migrated between nodes, Redis returns an ASK response instead of MOVED. Unlike MOVED (permanent redirect), ASK is a one-time redirect that requires sending the ASKING command to the target node before retrying the original query. The implementation: - Detects ASK responses alongside existing MOVED handling - Sends ASKING command to the target node before retrying - Reuses the MOVED redirect infrastructure (endpoint lookup, reconnection, retry logic) Also refactor parse_moved_reply() into parse_redirect_reply() that accepts the prefix as a parameter, with inline wrappers parse_moved_reply() and parse_ask_reply() for backward compatibility. Fix the hash slot calculation in redisHash(): replace the bitwise AND operator with modulo using the standard Redis cluster slot count (16384). The previous code used '& con->slots_assigned' which only produces correct results when slots_assigned is a power-of-2 minus 1. Using the spec-defined constant is always correct. Partially addresses OpenSIPS#2811
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This appears to be a partial duplicate of #3815 |
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Summary
Add support for Redis ASK redirects during cluster resharding and fix the hash slot calculation.
ASK Redirect Handling
When a Redis cluster is resharding (migrating slots between nodes), the source node returns an
ASKresponse instead ofMOVED. The key difference:ASKINGto the target node before retryingWithout ASK handling, queries during resharding operations fail with unhandled error responses. This completes the cluster redirect support started in #3639.
Implementation
ASKINGcommand to the target node before retrying the original queryparse_moved_reply()intoparse_redirect_reply()that accepts the prefix as a parameter, with inline wrappersparse_moved_reply()andparse_ask_reply()for backward compatibilityHash Slot Fix
Replaces
crc16(...) & con->slots_assignedwithcrc16(...) % REDIS_CLUSTER_SLOTS(16384). The bitwise AND only produces correct modulo results when the operand is2^n - 1. Using the spec-defined constant (RFC: Redis Cluster Specification) is always correct regardless of theslots_assignedvalue.Testing
-Wall -Wextra -Werror, zero warningsPartially addresses #2811