help request: plugins run,why step num is 2

[ghost]

Description

for i = 1, #plugins, 2 why the step num increase is 2?

[Hazel6869]

@Brucepower0223 Hi,this is the case in the array [function pointer 1, parameter 1, function pointer 2, parameter 2]

[pixeldin]

Hello @Brucepower0223, maybe this will help.

I add some log to figure out what hanppend inside here. As we seen in this code the plugins is actually like a Lua table.
What I did is trying to dump the table's value with some log for debug, and runing a test case that with any plugin, that will print out the necessary info into nginx log. (Try to locate at "t/servroot/logs/error.log")

Step 1:

Edit the "apisix/plugin.lua" file

 local local_plugins_hash    = core.table.new(0, 32)
 local stream_local_plugins  = core.table.new(32, 0)
 local stream_local_plugins_hash = core.table.new(0, 32)
+local inspect = require('inspect')
 
// ...
         and phase ~= "body_filter"
         and phase ~= "delayed_body_filter"
     then
+        core.log.info("# Pixel-debug enter: plugins len: " .. #plugins)
+        core.log.info("# Pixel-debug plugins content: " .. inspect(plugins))
         for i = 1, #plugins, 2 do
             local phase_func
             if phase == "rewrite_in_consumer" then

Step 2:

Run a test file with some plugin:

ngx.HTTP_PUT,
[[{
    "plugins": {
        "jwt-auth": {
            "header": "jwt-header",
            "query": "jwt-query",
            "cookie": "jwt-cookie",
            "hide_credentials": true
        },
        "limit-count": {
            "count": 2,
            "time_window": 60,
            "rejected_code": 503,
            "key": "remote_addr"
        }                        
    },
    ...

Find some log here:

2022/11/17 00:20:10 [info] 22707#22707: *3 [lua] plugin.lua:936: common_phase(): # Pixel-debug enter: plugins len: 4, client: 127.0.0.1, server: localhost, request: "GET /get HTTP/1.1", host: "localhost"
2022/11/17 00:20:10 [info] 22707#22707: *3 [lua] plugin.lua:937: common_phase(): # Pixel-debug plugins 
content: { {
    api = <function 1>,
    check_schema = <function 2>,
    // skip some schema...
    name = "jwt-auth",
    priority = 2510,
    rewrite = <function 3>,
    // hide some schema...
    type = "auth",
    version = 0.1
  }, {
    _skip_rewrite_in_consumer = true,
    algorithm = "HS256",
    base64_secret = false,
    exp = 86400,
    key = "user-key",
    lifetime_grace_period = 0,
    secret = "my-secret-key"
  }, {
    access = <function 4>,
    check_schema = <function 5>,
    name = "limit-count",
    priority = 1002,
    // skip some schema...
  }
  // skip something else field...
}
...

---

As we can see, the plugins content structure is defined and separated by the field name. In this case which loading two plugins( jwt-auth and limit-count ).
The func loading is an interval of 2.