Création de microservices haute performance avec gRPC, Ballerina et Go

Salut, Habr. Nous invitons les futurs étudiants du cours «Architecte logiciel» à participer à un webinaire ouvert sur le thème «Idempotence et commutabilité de l' API dans les files d'attente et HTTP» .



Nous partageons également la traduction de documents utiles.














. , . API HTTP, (JSON, XML . .), , (REST) ​​ . 





REST . OpenAPI , , REST API. API API, , , -. REST API HTTP GraphQL, .





— , . . , . REST API HTTP, . , , gRPC, .





gRPC?

gRPC — API (Remote procedure call — RPC) . RPC, , . , Thrift Avro, gRPC (interface description language — IDL). gRPC HTTP/2 — , gRPC REST HTTP/1.1. 





gRPC Protocol Buffers, , . , , () Protocol Buffers, .





gRPC

Figure 1. Segment d'architecture de microservices d'un magasin de vente au détail en ligne
1. -

, , . 1 - , Ballerina Golang, , -. gRPC , , . 









syntax="proto3";
 
package retail_shop;
 
service OrderService {
   rpc UpdateOrder(Item) returns (Order);
}  
message Item {
   string itemNumber = 1;
   int32 quantity = 2;
}
message Order {
   string itemNumber = 1;
   int32 totalQuantity = 2;
   float subTotal = 3;
      
      



1. Order (order.proto)





Order . gRPC Ballerina gRPC / . 





$ ballerina grpc --mode service --input proto/order.proto --output gen_code
      
      







import ballerina/grpc;
listener grpc:Listener ep = new (9090);
 
service OrderService on ep {
   resource function UpdateOrder(grpc:Caller caller, Item value) {
       // Implementation goes here.
 
       // You should return an Order
   }
}
public type Order record {|
   string itemNumber = "";
   int totalQuantity = 0;
   float subTotal = 0.0;
  
|};
public type Item record {|
   string itemNumber = "";
   int quantity = 0;
  
|}; 
      
      



2. (OrderServicesampleservice.bal).





gRPC ​​ service



Ballerina, gRPC rpc ​​ resource function



Ballerina, gRPC — record







Order Ballerina OrderService gRPC





OrderService Cart. Ballerina.





$ ballerina grpc --mode client --input proto/order.proto --output gen_code
      
      



, . , gRPC gRPC.





public remote function UpdateOrder(Item req, grpc:Headers? headers = ()) returns ([Order, grpc:Headers]|grpc:Error) {
      
       var payload = check self.grpcClient->blockingExecute("retail_shop.OrderService/UpdateOrder", req, headers);
       grpc:Headers resHeaders = new;
       anydata result = ();
       [result, resHeaders] = payload;
       return [<Order>result, resHeaders];
   }
};
      
      



3.





Ballerina gRPC, , UpdateOrder



.





Checkout , , Cart. stream Order



.





syntax="proto3";
package retail_shop;
 
service CheckoutService {
   rpc Checkout(stream Order) returns (FinalBill) {}
}
message Order {
   string itemNumber = 1;
   int32 totalQuantity = 2;
   float subTotal = 3;
}
message FinalBill {
   float total = 1;
}
      
      



4. Checkout (checkout.proto)





checkout.proto



, ballerina grpc



.





$ ballerina grpc --mode service --input proto/checkout.proto --output gencode





gRPC

Cart () , , , . :





service CheckoutService on ep {
   resource function Checkout(grpc:Caller caller, stream<Order,error> clientStream) {
       float totalBill = 0;
 
       //Iterating through streamed messages here
       error? e = clientStream.forEach(function(Order order) {
           totalBill += order.subTotal;           
       });
       //Once the client completes stream, a grpc:EOS error is returned to indicate it
       if (e is grpc:EOS) {
           FinalBill finalBill = {
               total:totalBill
           };
           //Sending the total bill to the client
           grpc:Error? result = caller->send(finalBill);
           if (result is grpc:Error) {
               log:printError("Error occurred when sending the Finalbill: " + 
result.message() + " - " + <string>result.detail()["message"]);
           } else {
               log:printInfo ("Sending Final Bill Total: " + 
finalBill.total.toString());
           }
           result = caller->complete();
           if (result is grpc:Error) {
               log:printError("Error occurred when closing the connection: " + 
result.message() +" - " + <string>result.detail()["message"]);
           }
       }
       //If the client sends an error instead it can be handled here
       else if (e is grpc:Error) {
           log:printError("An unexpected error occured: " + e.message() + " - " +
                                                   <string>e.detail()["message"]);
       }   
   }
}
      
      



5. Service   CheckoutService



(CheckoutServicesampleservice.bal)





grpc:EOS



, , ( ) caller object



.





CheckoutService :





$ ballerina grpc --mode client --input proto/checkout.proto --output gencode
      
      



Cart. Cart REST API: , — . , gRPC Order . Checkout , , Checkout gRPC . Ballerina Stream Client Object



gRPC. 2 , Ballerina.





Figure 2. Streaming du client gRPC Ballerina 
2. gRPC Ballerina 

CheckoutService resource function checkout Cart. , gRPC Stock, Golang, , .





syntax="proto3";
package retail_shop;
option go_package = "../stock;gen";
import "google/api/annotations.proto";
 
service StockService {
   rpc UpdateStock(UpdateStockRequest) returns (Stock) {
       option (google.api.http) = {
           // Route to this method from POST requests to /api/v1/stock
           put: "/api/v1/stock"
           body: "*"
       };
   }
}
message UpdateStockRequest {
   string itemNumber = 1;
   int32 quantity = 2;
}
message Stock {
   string itemNumber = 1;
   int32 quantity = 2;
      
      



6. Stock (stock.proto)





UpdateStock REST API API, gRPC . grpc-gateway — protoc, gRPC -, RESTful JSON API gRPC. 





 





Figure 3: passerelle grpc
3: grpc-gateway

grpc-gateway API- gRPC REST.





gRPC Golang:





protoc -I/usr/local/include -I. \
-I$GOROOT/src \
-I$GOROOT/src/github.com/grpc-ecosystem/grpc-gateway/third_party/googleapis \
--go_out=plugins=grpc:. \
stock.proto
      
      



grpc-gateway Golang:





protoc -I/usr/local/include -I. \
-I$GOROOT/src \
-I$GOROOT/src/github.com/grpc-ecosystem/grpc-gateway/third_party/googleapis \
--grpc-gateway_out=logtostderr=true:. \
stock.proto
      
      



stock.swagger.json:





protoc -I/usr/local/include -I. \
-I$GOROOT/src \
-I$GOROOT/src/github.com/grpc-ecosystem/grpc-gateway/third_party/googleapis \
-I$GOROOT/src \
--swagger_out=logtostderr=true:../stock/gen/. \
./stock.proto
      
      



git microservices-with-grpc README.md.





gRPC , . gRPC , , . , gRPC , REST API, , grpc-gateway. , , gRPC, Deadlines, Cancellation, Channels xDS, .





Ballerina gRPC, :





  • Unary Blocking





  • Unary Non-Blocking





  • Server Streaming





  • Client Streaming





  • Bidirectional Streaming





Golang gRPC, , , , Interceptor, Deadlines, Cancellation, Channels gRPC , . git grpc-go, .





:






"Software Architect".



" API HTTP".












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