If I want to add a new command to the redis server, where should I start in the source code?

Comment From: itamarhaber

Hello @MasterL-min

The easiest way to extend Redis with new commands and data structures is with a module. Please take a look at the documentation for more details and examples on writing one.

Comment From: bugwz

@MasterL-min Also u can find the command code struct redisCommand redisCommandTable[] in src/commands.c.

Comment From: MasterL-min

Hello @MasterL-min

The easiest way to extend Redis with new commands and data structures is with a module. Please take a look at the documentation for more details and examples on writing one.

Thanks a lot,it is really easy to extend Redis with a module，and i also want to know where could I start if I want to make modifications on the command of redis itself

Comment From: itamarhaber

where could I start if I want to make modifications on the command

That depends on the command. Each command is described by a JSON file under src/commands. You can find the name of the C function each command is implemented with under the "function" field.

For example, the SET command's JSON file is at src/commands/set.json and has the value "setCommand" as the "function"'s key value: https://github.com/redis/redis/blob/7.0/src/commands/set.json#L8

If you search the code, you'll find the implementation of "setCommand" in the src/t_string.c: https://github.com/redis/redis/blob/7.0/src/t_string.c#L292

Comment From: MasterL-min

where could I start if I want to make modifications on the command

That depends on the command. Each command is described by a JSON file under src/commands. You can find the name of the C function each command is implemented with under the "function" field.

For example, the SET command's JSON file is at src/commands/set.json and has the value "setCommand" as the "function"'s key value: https://github.com/redis/redis/blob/7.0/src/commands/set.json#L8

If you search the code, you'll find the implementation of "setCommand" in the src/t_string.c: https://github.com/redis/redis/blob/7.0/src/t_string.c#L292

I want to know why when I only changed the const char *strflags parameter in the RedisModule_CreateCommand function in the Module sample code, it shows hellorand.so initialization failed after running the redis server. I didn't even change the content of the internal function

Comment From: MasterL-min

where could I start if I want to make modifications on the command

That depends on the command. Each command is described by a JSON file under src/commands. You can find the name of the C function each command is implemented with under the "function" field.

For example, the SET command's JSON file is at src/commands/set.json and has the value "setCommand" as the "function"'s key value: https://github.com/redis/redis/blob/7.0/src/commands/set.json#L8

If you search the code, you'll find the implementation of "setCommand" in the src/t_string.c: https://github.com/redis/redis/blob/7.0/src/t_string.c#L292

D0LPZL20YM$4E_UA2JQ$8ML like the RedisModule_CreateCommand(ctx,"helloworld.rand", HelloworldRand_RedisCommand, "fast random", 0, 0, 0) == REDISMODULE_ERR),I just change the "fast random" to the "fast send",then the redis server can not load the module correctly.

Comment From: itamarhaber

That is because "send" is a random word rather than a valid command flag. For the full list of supported command flags please refer to the docs: https://redis.io/docs/reference/modules/modules-api-ref/#redismodule_createcommand

Comment From: itamarhaber

Keep in mind that this issue tracker should be used for reporting bugs or proposing improvements to the Redis server. Questions should be directed to the community:

Comment From: MasterL-min

That is because "send" is a random word rather than a valid command flag. For the full list of supported command flags please refer to the docs: https://redis.io/docs/reference/modules/modules-api-ref/#redismodule_createcommand

Thank you very much for your help