Cluster asm api #37

tezc · 2025-06-18T08:13:59Z

dummy impl for the cluster plugin api

/* API for implementation/plugin
 *
 * - On destination side, implementation calls clusterAsmRequest(ASM_REQUEST_IMPORT_START)
 *   to start the import operation
 * - Redis calls clusterAsmOnEvent() when an event occurs.
 * - On the source side, Redis will call clusterAsmOnEvent(ASM_EVENT_MIGRATE_WAIT_PAUSE)
 *   when the write pause is needed.
 * - Implementation stops the traffic to the slots and calls clusterAsmRequest(ASM_REQUEST_MIGRATE_PAUSED)
 * - On the destination side, Redis calls clusterAsmOnEvent(ASM_EVENT_IMPORT_WAIT_FINALIZE)
 *   when the import is completed.
 * - Plugin calls clusterAsmRequest(ASM_REQUEST_CONFIG_UPDATED) to notify Redis
 *   that the config is updated.
 *
 * Sequence diagram for import:
 *   - Note: shows only the events that plugin needs to react.
 *
 * ┌───────────────┐              ┌───────────────┐         ┌───────────────┐             ┌───────────────┐
 * │ Destination   │              │ Destination   │         │    Source     │             │ Source        │
 * │ Cluster plugin│              │ Master        │         │    Master     │             │ Cluster plugin│
 * └───────┬───────┘              └───────┬───────┘         └───────┬───────┘             └───────┬───────┘
 *         │                              │                         │                             │
 *         │ ASM_REQUEST_IMPORT_START     │                         │                             │
 *         ├─────────────────────────────►│                         │                             │
 *         │                              │CLUSTER SYNCSLOTS <arg>  │                             │
 *         │                              ├────────────────────────►│                             │
 *         │                              │                         │                             │
 *         │                              │  SNAPSHOT(restore cmds) │                             │
 *         │                              │◄────────────────────────┤                             │
 *         │                              │  Repl stream            │                             │
 *         │                              │◄────────────────────────┤                             │
 *         │                              │                         │ASM_EVENT_MIGRATE_WAIT_PAUSE │
 *         │                              │                         ├────────────────────────────►│
 *         │                              │                         │ ASM_REQUEST_MIGRATE_PAUSED  │
 *         │                              │                         │◄────────────────────────────┤
 *         │                              │ Drain repl stream       │                             │
 *         │                              │◄────────────────────────┤                             │
 *         │ASM_EVENT_IMPORT_WAIT_FINALIZE│                         │                             │
 *         │◄─────────────────────────────┤                         │                             │
 *         │                              │                         │                             │
 *         │ ASM_REQUEST_CONFIG_UPDATED   │                         │                             │
 *         ├─────────────────────────────►│                         │ ASM_REQUEST_CONFIG_UPDATED  │
 *         │                              │                         │◄────────────────────────────┤
 *         │                              │                         │                             │
 */

src/cluster_asm.h

src/cluster.c

src/cluster_asm.c

ShooterIT · 2025-06-23T06:39:31Z

cool job, your code makes the responsibilities and interactions between the plugin and redis much clearer to me!

src/cluster_asm.c

tezc · 2025-06-24T07:56:36Z

src/cluster.h

+
+
+/* Called when an ASM event occurs to notify implementation/plugin. */
+int clusterAsmOnEvent(slotRangeArray *slot_ranges, int event, void *arg);


EDIT: Please review last version in cluster-asm branch.

@jhershberg please comment if the above api makes sense.

Some notes/concerns:

The above API uses two functions with different operations. So far, it seemed good enough but I wonder if an operation would need to pass more arguments. Then, we may prefer to switch to function calls per operation.

I see that plugin handles sds already. So, I assume we can pass strings/errors as sds. Plugin should implement struct slotRangeArray and struct slotRange.

For the above API, task identificator is the slot ranges. So, we are not using another kind of an ID, say a sequential integer, but this is how it will be for OSS. We don't have identificator there as well, operator will distinguish operations based on slot ranges.

I totally ignored the case the plugin will work on its own thread, please comment if we need adjustment for it.

cluster asm api

tezc added 5 commits June 18, 2025 11:02

cluster asm api

a0e96db

v2

e6960f5

v3

8cd6672

diagram

e957dfe

cleanup

d82d157

tezc marked this pull request as ready for review June 19, 2025 08:49

tezc added 4 commits June 19, 2025 11:50

comment

53c3658

minor

1458fad

doc

0f62098

doc

4f3d82c

tezc commented Jun 19, 2025

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tezc requested a review from ShooterIT June 19, 2025 10:02