Add support for MODULE LOADEX command

[ktsivkov]

Adding tests for it is too tricky.
It requires the redis-server to be run with flag --enable-module-command yes and the existance of an .so file for the module to be loaded.
implement #2405

[SoulPancake]

How are you planning to test this ? @ktsivkov

[ktsivkov]

I will be unable to do it this week, but my idea is to add inside the testing script to pull one of the officially supported plugins and use it for the test.

Unless you have a better idea that could be more lightweight?
@SoulPancake

[chayim]

@ktsivkov I don't think you can do this that way - purely because you'll need a binary, guaranteed to be compatible on an OS, it's different for each user, etc.

IMHO for this (specifically) you should validate the syntax of the command - i.e use a mock.

[ktsivkov]

@chayim Was checking yesterday @SoulPancake's issue here go-redis/redismock#69 but it looks like that is not actually testing the command's syntax. Did you mean some other type of mock?

[SoulPancake]

@ktsivkov
From what I understand
A straightforward way to do the syntax check would be to just test the syntax of the LoadexConfig struct and the ToArgs() function in the following way :

It("converts the configuration to a slice of arguments correctly", func() {
        conf := &LoadexConfig{
            Path: "/path/to/your/module.so",
            Conf: map[string]interface{}{
                "param1": "value1",
                "param2": "value2",
            },
            Args: []interface{}{
                "arg1",
                "arg2",
            },
        }

        args := conf.ToArgs()

        // Test if the arguments are in the correct order
        expectedArgs := []interface{}{
            "MODULE",
            "LOADEX",
            "/path/to/your/module.so",
            "CONFIG",
            "param1",
            "value1",
            "CONFIG",
            "param2",
            "value2",
            "ARGS",
            "arg1",
            "ARGS",
            "arg2",
        }

        Expect(args).To(Equal(expectedArgs))
    })
  
    
 Feels redundant to me tbh
 Not sure how else we can write a useful test

[ktsivkov]

@chayim I believe the PR is ready for a review.
I did what @SoulPancake suggested me to, but I also wrote a test that checks that the command is successfully executed on the server, and that it fails loading the module. At this point this is the closest I could get to testing the full behavior.

[SoulPancake]

@monkey92t
Can you please review this ?

[monkey92t]

Good