FUNCTION LOAD

FUNCTION LOAD compiles a library and registers its functions. The code must start with a metadata line naming the engine and the library, such as #!lua name=mylib; library names may contain letters, digits and underscores. The code then calls redis.register_function once per function, either as redis.register_function('name', callback) or with a table giving function_name, callback, and optionally flags and description.

The library is saved with the dataset and replicated. Loading a library whose name is taken fails unless you pass REPLACE, which swaps the old library for the new one in one step. No function name may be registered by two libraries.

Options

Option	Effect
REPLACE	Replace a library of the same name instead of failing.

Return value

Case	RESP2	RESP3
Loaded	Bulk string: the library name	Bulk string

Errors:

• ERR Library '<name>' already exists without REPLACE.
• ERR Function <name> already exists when another library registers that function.
• ERR No functions registered when the code registers no function.
• ERR Missing library metadata, ERR Library name was not given, ERR Engine '<engine>' not found and similar errors for a bad first line.
• ERR Error compiling function: ... when the code does not compile.
• ERR Unknown option given: <option> for an option other than REPLACE.

Examples

127.0.0.1:6379> FUNCTION LOAD "#!lua name=util\nredis.register_function('echo', function(keys, args) return args[1] end)"
"util"
127.0.0.1:6379> FUNCTION LOAD "#!lua name=util\nredis.register_function('echo', function(keys, args) return args[1] end)"
(error) ERR Library 'util' already exists
127.0.0.1:6379> FUNCTION LOAD REPLACE "#!lua name=util\nredis.register_function('echo', function(keys, args) return 'v2: ' .. args[1] end)"
"util"
127.0.0.1:6379> FCALL echo 0 "hi"
"v2: hi"

Compatibility

Same as Redis 7 and Valkey 8.

See also

FCALL, FUNCTION LIST, FUNCTION DELETE