ok, I publish the image.
image link: https://www.processon.com/view/link/608651fa1e08537c0d341365

Zhiyuan Ju <juzhiy...@apache.org> 于2021年4月26日周一 上午11:53写道:

> Hi, ZhengSong,
>
> You image is broken due to we could only use plain text in mailing list :)
>
> Best Regards!
> @ Zhiyuan Ju <https://github.com/juzhiyuan>
>
>
> ZhengSong Tu <tzssanggl...@gmail.com> 于2021年4月26日周一 上午11:47写道:
>
> > I have sketched the flow of the java side of the plugin runner
> > [image: APISIX 运行 Java 插件.png]
> >
> > And I have some questions to clarify.
> >
> > 1. How does the plugin runner load the client's code?
> >     It's up to each runner to figure it out according to its own
> > language's ecology. Take java as an example,
> > the user develops with the PDK provided by us, and packages the custom
> > plugin code into a jar and puts it in the specified location. When the
> > plugin runner starts, it loads the jar package in this location by means
> of
> > a custom dynamic ClassLoader or something like that.
> >
> > 2. How do users develop?
> >     Just provide the filter chain like Spring Cloud Gateway. Users can
> > register their own filters. And the PDK is a jar, with some defined
> > interfaces such as pre, post, etc., and some objects such as request,
> > header, etc.
> >
> > 3. How to debug?
> >     Option 1:  APISIX provides debugging mode for java plugins, this time
> > it is not APISIX to start the plugin runner, but the user himself
> downloads
> > the plugin runner code and runs the main method to start it, so as to
> > construct a request to access APISIX, APISIX will pass the context of the
> > request to the plugin runner, and then use it to debug java code.
> >     Option 2:  java remote debug.
> >
> >
> >
> > Zexuan Luo <spacewan...@apache.org> 于2021年4月19日周一 下午6:18写道:
> >
> >> Here is the new flatbuffer schema:
> >>
> >>
> https://github.com/spacewander/incubator-apisix/blob/step1/apisix/plugins/ext-plugin/ext-plugin.fbs
> >>
> >> Zexuan Luo <spacewan...@apache.org> 于2021年4月16日周五 下午2:52写道:
> >> >
> >> > 1. Background
> >> >
> >> > APISIX currently only supports writing plugins in Lua. If other
> >> > languages are supported, it will greatly broaden the APISIX ecosystem
> >> > and user base.
> >> >
> >> > 2. Solution
> >> >
> >> > Since WASM is not yet mature, we consider implementing it through
> local
> >> IPC.
> >> >
> >> > For the sake of discussion, the following will assume that the plugin
> >> > is written in Java. However, in practice, our solution can be
> >> > interfaced with other languages.
> >> >
> >> > 2.1 Terminology
> >> >
> >> > Several terms are defined here.
> >> >
> >> > Plugin Runner: The service that runs the plugin, written in the same
> >> > language as the plugin. In the first version, we assume that there
> >> > will be only one Plugin Runner.
> >> >
> >> > 2.2 Plugin Runner lifecycle
> >> >
> >> > To simplify user operation and reduce the difficulty of upgrading,
> >> > Plugin Runner is managed by APISIX.
> >> >
> >> > APISIX starts the Plugin Runner when it starts and ends it when it
> >> > ends. if the Plugin Runner quits in the middle, APISIX will restart it
> >> > automatically.
> >> >
> >> > 2.3 Timing of APISIX communication with Plugin Runner
> >> >
> >> > ```
> >> > Router ----> Global Plugin (written in Lua) ---> Ext Plugin
> >> > (ext-plugin-pre-req) ----> Lua Plugin (Router)
> >> > ---> Ext plugin (ext-plugin-post-req) ---> Upstream
> >> > ```
> >> >
> >> > Running the Ext Plugin in the Global Plugin is not supported at this
> >> > time, as the global logic can be executed uniformly in the Plugin
> >> > Runner.
> >> >
> >> > Running Ext Plugin after getting an upstream response is not supported
> >> > at this time. We can support it later with a buffering response.
> >> >
> >> > ext-plugin-pre runs before all non-global Lua plugins, and
> >> > ext-plugin-post runs after all non-global Lua plugins.
> >> >
> >> > 2.4 How APISIX communicates with Plugin Runner
> >> >
> >> > APISIX communicates with Plugin Runner through a unix socket. The
> >> > communication protocol is as follows.
> >> >
> >> > 2.4.1 Communication format
> >> >
> >> > ```
> >> > 1 byte of type + 3 bytes of length + data
> >> > ```
> >> >
> >> > The type can be 0 ~ 7, and the length can be [0, 8M). data length is
> >> > determined by length.
> >> > Since Ext Plugin usually does not exchange too much data, 8M should be
> >> > enough. The reason for taking 4 bytes is to keep the header small
> >> > enough to be read efficiently.
> >> >
> >> > The current type takes the following values.
> >> >
> >> > 0 means error
> >> > 1 means prepare_conf
> >> > 2 means http_req_call
> >> >
> >> > The data is serialized in capnproto, a binary serialization format.
> >> >
> >> > capnproto is supported by many programming languages:
> >> > https://capnproto.org/otherlang.html
> >> >
> >> > The advantages of choosing capnproto are.
> >> > 1. focus on serialization performance
> >> > 2. partial deserialization support, so that decode can be done only
> >> > when it is needed
> >> >
> >> > 2.4.2 Communication steps
> >> >
> >> > Each ext plugin will have the following configuration.
> >> >
> >> > ```
> >> > {
> >> >     "conf": [
> >> >         {
> >> >             "name": "configuration name",
> >> >             "value": "configuration value"
> >> >         }
> >> >     ],
> >> >     "extra_info": [
> >> >                 ...
> >> >     ]
> >> > }
> >> > ```
> >> >
> >> > conf can be used to set the execution configuration of the
> >> > plugin-related requests inside Plugin Runner.
> >> >
> >> > The default data sent to Plugin Runner is only the most common
> >> > information. If you want additional information, you need to declare
> >> > it in extra_info beforehand.
> >> >
> >> > To save communication costs, conf is sent separately.
> >> >
> >> > 1. APISIX will check if conf has a corresponding token in the local
> >> cache.
> >> >  2. If not, APISIX sends a prepare_conf request to ask Plugin Runner
> >> > to cache the conf and return a token.
> >> > (Note that Plugin Runner's cache time needs to be longer than APISIX's
> >> > cache time.)
> >> > 3. APISIX sends an http_req_call request to Plugin Runner.
> >> > 4. Plugin Runner executes the request and returns a response to
> APISIX.
> >> > 5. APISIX processes the request based on the response
> >> >
> >> > 2.4.3 proto
> >> >
> >> > Refer to https://capnproto.org/language.html
> >> >
> >> > The following is the proto for error
> >> >
> >> > response
> >> > ```
> >> > enum ErrorCode {
> >> >     BAD_REQUEST @0; # Plugin Runner can't understand APISIX
> >> >     SERVICE_UNAVAILABLE @1; # Plugin Runner can't handle the request
> >> >     CONF_TOKEN_NOT_FOUND @2;
> >> > }
> >> > struct ErrorResp {
> >> >     Code @0 :ErrorCode;
> >> > }
> >> > ```
> >> >
> >> > The following is the proto of prepare_conf
> >> >
> >> > request
> >> > ```
> >> > struct PrepareConfReq {
> >> >     conf @0 :List(Pair);
> >> > }
> >> > ```
> >> >
> >> > Response
> >> > ```
> >> > struct PrepareConfResp {
> >> >     conf_token @0 :UInt32;
> >> > }
> >> > ```
> >> >
> >> > Here is the proto for http_req_call
> >> >
> >> > request
> >> > ```
> >> > struct Pair {
> >> >     name @0 :Text;
> >> >     value @1 :Text;
> >> > }
> >> > struct PairData {
> >> >     name @0 :Text;
> >> >     value @1 :Data;
> >> > }
> >> > enum Method {
> >> >         GET @0;
> >> >         ...
> >> > }
> >> >
> >> > struct HTTPReqCallReq {
> >> >     id @0 :UInt32;
> >> >     src_ip @1 :Data;
> >> >
> >> >     method @2 :Method;
> >> >
> >> >     path @3 :Text;
> >> >     args @4 :List(Pair);
> >> >     headers @5 :List(Pair);
> >> >
> >> >     conf_token @6 :UInt32;
> >> >
> >> >     extra_info @7 :List(PairData);
> >> > }
> >> > ```
> >> >
> >> > Response
> >> > ```
> >> > struct HTTPReqCallResp {
> >> >     id @0 :UInt32;
> >> >
> >> >     struct Stop {
> >> >         status @0 :UInt16;
> >> >         headers @1 :List(Pair);
> >> >         body @2 :Data;
> >> >     }
> >> >     struct Rewrite {
> >> >         path @0 :Text;
> >> >         headers @1 :List(Pair);
> >> >         # Note that args are modified in full.
> >> >         # Either empty, meaning no args need to be moved
> >> >         # or the entire modified args, not the incrementally changed
> >> parts
> >> >         args @2 :List(Pair);
> >> >     }
> >> >
> >> >     # What needs to be done when the response is received action
> >> >     action :union {
> >> >         # Do nothing
> >> >         continue @1 :Void;
> >> >         # Equivalent to core.response.exit(status, body), allowing
> >> > additional headers to be set
> >> >         stop @2 :Stop;
> >> >         # Rewrite the request
> >> >         rewrite @3 :Rewrite;
> >> >     }
> >> > }
> >> > ```
> >> >
> >> > 2.4.4 Error handling
> >> >
> >> > Logging and returning 503 error codes
> >> >
> >> > 2.4.5 Environment variables
> >> >
> >> > APISIX configures the Plugin Runner with a number of environment
> >> > variables when it is started.
> >> >
> >> > APISIX_LISTEN_ADDRESS: the address that the Plugin Runner needs to
> >> listen to
> >> > APISIX_CONF_EXPIRE_TIME: Plugin Runner needs to cache conf for longer
> >> than this
> >>
> >
>

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