[SCB-1929] provide new mechanism: Filter

• Type: New Feature
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: java-chassis-3.0.0
• Component/s: Java-Chassis
• Assignee: liubao
• Reporter: Jimin Wu
• Created: 22/May/20 07:59
• Updated: 04/Sep/23 01:45
• Resolved: 04/Sep/23 01:45

Description

currently, we have extensions:

1. HttpClientFilter
2. HttpServerFilter
3. Handler
4. ProducerInvokeExtension

and we hard code to invoke all the extensions:

1. consumer:
   1. invoke all handlers
   2. invoke all HttpClientFilters
2. producer:
   1. schedule to operation related executor
   2. invoke all HttpServerFilters
   3. invoke all handlers

PROBLEMS:

1. all these extensions are about invocation, just have different prototype
2. for consumer
   1. when a sync invocation failed, and want to retry, retry schedule is conflict to sync mechanism
3. for producer
   1. qps-limiter should invoke before schedule, currently we hard code it
   2. if want to write reactive extension before schedule, to not care for controller method is sync or async, currently can not do it
   3. if executor is a real thread pool, and a reactive extension after schedule will break thread schedule plan, that maybe will cause block event loop
4. exception convert only avaiable for controller method invoke, but all extensions exception need convert too

SOLUTION:

provide new mechanism: Filter, to unify all the extensions, and change main invocation process flow from hard code to by configuration

1. prototype:

   public @interface FilterMeta {
     String name();
   
     /**
      *
      * @return can be used for the specific invocation type
      */
     InvocationType[] invocationType() default {CONSUMER, PRODUCER};
   
     /**
      *
      * @return true to use same instance for each filter chain
      */
     boolean shareable() default true;
   }
   
   public interface Filter {
     CompletableFuture<Response> onFilter(Invocation invocation, FilterNode nextNode);
   }
   

2. configuration

   servicecomb:
     filter-chains:
       enabled: true
       transport-filters:
         #default-consumer-transport:
         #  rest: rest-client-codec
         #  highway: highway-client-codec
         default-producer-tranport:
           rest: rest-server-codec
           highway: highway-server-codec
       consumer:
         default: simple-load-balance
         #default: simple-load-balance, default-consumer-transport, transport-client
         # samples for customize microservice filter chain
         #policies:
         #  ms-1: retry, load-balance, transport-client, ms-1-consumer-transport
       producer:
         default: default-producer-tranport, schedule, producer-operation
         # samples for customize microservice filter chain
         #policies:
         #  ms-1: qps-limiter, ms-1-producer-transport, schedule, producer-operation
   

   1. customize full flow of invocation
   2. microservice scope chain
   3. schema or operation scope chain, if have requirements in the future
   4. invoke exception converter when throwing a exception for all filter

COMPATIBLE:

1. wrap old HttpClientFilters to a Filter
2. wrap old HttpServerFilters to a Filter
3. wrap old consumer handlers to a Filter
4. wrap old producer handlers to a Filter
5. pre-define old filter chains, and default to old chains

Issue Links

• Blocked: SCB-1938 OperationConfig can get in pool timeout by transport name
• Blocked: SCB-1946 add new exception converter for all filters, not only the last one
• Blocked: SCB-1947 define Filter and filter chain
• Blocked: SCB-1948 cache invocation.producerArguments, avoid build one more time for validator
• Blocked: SCB-1951 enhance HttpTransportContext
• Blocked: SCB-1952 enhance HighwayTransportContext
• Blocked: SCB-1955 create unify producer invocation flow
• Blocked: SCB-1959 add rest invocation creator
• Blocked: SCB-1961 add rest server codec filter
• Blocked: SCB-1962 add highway server codec filter
• Blocked: SCB-1965 add zipkin filter
• Blocked: SCB-1966 print filter chain information after bootup
• Blocked: SCB-1967 add simple load balance
• Blocked: SCB-1968 add producer operation filter
• Blocked: SCB-1979 load filter chains
• Blocked: SCB-1980 add TransportFilters to select chain by transport in runtime
• Blocked: SCB-1981 add filter chain to SCBEngine
• Blocked: SCB-1982 add validator filter
• Blocked: SCB-1985 allow producer invocation process by filter chain
• Blocked: SCB-1987 adjust test code for filter chain mode
• Blocked: SCB-1992 tiny improve about InvocationException
• Blocked: SCB-2029 tiny improve to make extend filter features easier
• Blocked: SCB-2033 inject spring bean to filter instance automatically
• Blocked: SCB-2034 move create validator to init to use injected spring bean
• Blocked: SCB-2037 utils for get CompletableFuture result in sync mode
• Blocked: SCB-2141 add RestClientTransportContext
• Blocked: SCB-2142 add RestClientEncoder
• Blocked: SCB-2146 add RestClientDecoder
• Blocked: SCB-2147 add RestClientCodecFilter
• Blocked: SCB-2148 add RestClientSender
• Blocked: SCB-2149 add RestClientSenderFilter
• Blocked: SCB-2150 allowed modify host before create HttpClientRequest
• Blocked: SCB-2152 allow pojo invoker process by filter chain
• Blocked: SCB-2156 add HighwayClientFilter
• Blocked: SCB-2158 optimize exception log
• Blocked: SCB-2159 add TimeoutExceptionConverter
• Blocked: SCB-2169 optimize filter declare and chain config
• Blocked: SCB-2170 add configuration to control log invocation exception stack trace
• Blocked: SCB-2218 allow edge invocation process by filter
• Blocked: SCB-2251 make exception processor extendable