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ironfish / acmeco-widget

Akka gRPC Demo

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Akka gRPC Widget Service Demo

This project holds sample Akka gRPC for the Widget service.

Intro

This demo implements Akka gRPC for the Widget service. For more information on Akka gRPC and gRPC in general see the following:

Definitions, Implementations and Such...

In this demo we implement CRUD for the Widget Service's WidgetTeam. Some things to note:

  • The majority of the code is auto-generated in target/scala-2.13/akka-grpc/main/com/acmeco/widget directory. This code should not be edited.
  • The code in the above directory is generated from the src/main/protobuf/widget_team.proto file which looks something like:

Service Definition

This protobuf definition file includes both the messages as well as the service (rpc) definition.

syntax = "proto3";
package com.acmeco.widget;

import "google/protobuf/timestamp.proto";

// WidgetTeam message definition
message WidgetTeam {
  string id = 1;
  string name = 2;
  string activity_type = 3;
  string program_id = 4; // NOTE protobuf doesn't support UUIDs. Use string in hexadecimal format.
  google.protobuf.Timestamp modified = 5;
  string user = 6;
}

// Request and Response message definitions for each RPC method

// CreateWidgetTeam
message CreateWidgetTeamRequest {
  WidgetTeam widget_team = 1;
}

message CreateWidgetTeamResponse {
  WidgetTeam widget_team = 1;
}

// ReadWidgetTeam
message ReadWidgetTeamRequest {
  string id = 1;
}

message ReadWidgetTeamResponse {
  WidgetTeam widget_team = 1;
}

// ReadAllWidgetTeam
message ReadAllWidgetTeamsRequest {
  // string id = 1;
}

message ReadAllWidgetTeamsResponse {
  repeated WidgetTeam widget_teams = 1;
}

// UpdateWidgetTeam
message UpdateWidgetTeamRequest {
  WidgetTeam widget_team = 1;
}

message UpdateWidgetTeamResponse {
  WidgetTeam widget_team = 1;
}

// DeleteWidgetTeam
message DeleteWidgetTeamRequest {
  string id = 1;
}

message DeleteWidgetTeamResponse {
  bool success = 1;
  string message = 2;
}

// WidgetTeamService definition with CRUD operations
service WidgetTeamService {
  rpc CreateWidgetTeam(CreateWidgetTeamRequest) returns (CreateWidgetTeamResponse);
  rpc ReadWidgetTeam(ReadWidgetTeamRequest) returns (ReadWidgetTeamResponse);
  rpc ReadAllWidgetTeams(ReadAllWidgetTeamsRequest) returns (ReadAllWidgetTeamsResponse);
  rpc UpdateWidgetTeam(UpdateWidgetTeamRequest) returns (UpdateWidgetTeamResponse);
  rpc DeleteWidgetTeam(DeleteWidgetTeamRequest) returns (DeleteWidgetTeamResponse);
}

Compiling

To compile the code simply run sbt clean compile.

prompt> sbt clean compile
[info] welcome to sbt 1.9.3 (Eclipse Adoptium Java 11.0.20.1)
[info] loading settings for project acmeco-widget-build-build-build from metals.sbt ...
[info] loading project definition from /Users/duncan/Code/acmeco-widget/project/project/project
[info] loading settings for project acmeco-widget-build-build from metals.sbt ...
[info] loading project definition from /Users/duncan/Code/acmeco-widget/project/project
[success] Generated .bloop/acmeco-widget-build-build.json
[success] Total time: 0 s, completed Oct 2, 2023, 5:11:58 PM
[info] loading settings for project acmeco-widget-build from metals.sbt,plugins.sbt ...
[info] loading project definition from /Users/duncan/Code/acmeco-widget/project
[success] Generated .bloop/acmeco-widget-build.json
[success] Total time: 0 s, completed Oct 2, 2023, 5:11:58 PM
[info] loading settings for project acmeco-widget from build.sbt ...
[info] set current project to acmeco-widget (in build file:/Users/duncan/Code/acmeco-widget/)
[info] Executing in batch mode. For better performance use sbt's shell
[success] Total time: 0 s, completed Oct 2, 2023, 5:11:58 PM
[info] Compiling 1 protobuf files to /Users/duncan/Code/acmeco-widget/target/scala-2.13/akka-grpc/main
[info] Generating Akka gRPC service interface for com.acmeco.widget.WidgetTeamService
[info] Generating Akka gRPC client for com.acmeco.widget.WidgetTeamService
[info] Generating Akka gRPC service handler for com.acmeco.widget.WidgetTeamService
[info] compiling 19 Scala sources to /Users/duncan/Code/acmeco-widget/target/scala-2.13/classes ...
[success] Total time: 5 s, completed Oct 2, 2023, 5:12:03 PM
  • Note the generated code output: [info] Generating Akka gRPC service interface for com.acmeco.widget.WidgetTeamService
  • This will auto-generate the code found in target/scala-2.13/akka-grpc/main/com/acmeco/widget
  • Once this code is generated you can implement it as found in src/main/scala/com/acmeco/widget

Implementations

  • For this project, we create four implementation:
    • WidgetTeamClient.scala
    • WidgetTeamDAO.scala
    • WidgetTeamServer.scala
    • WidgetTeamServiceImpl.scala

WidgetTeamClient.scala

This class is a representation of a client written in Scala. Typically your client would be Javascript or something else that consumes gRPC.

WidgetTeamDAO.scala

This class is a DAO using an AtomicReference and a Scala Set[WidgetTeam] as a database mock. This class would be replace by something like a Slick or ScalaLikeJDBC implementation.

WidgetTeamServer.scala

While this project may look like it doesn't use much Akka because you don't see any Actors, that is not the case. It very much relies on Akka and Akka HTTP to implement the protobuf solution. In this class, we stand up an HTTP2 server with SSL enabled, all driven by Akka.

WidgetTeamServiceImpl.scala

This class is where we service the Request/Response cycle and call the underlying data store. Akka gRPC servers are implemented with Akka HTTP. In addition to the generated WidgetTeamService, a WidgetTeamServiceHandler was generated that wraps the implementation with the gRPC functionality to be plugged into an existing Akka HTTP server app.

Running

Running the Server

To run the server, execute the following in a terminal window:

prompt> sbt "runMain com.acmeco.widget.WidgetTeamServer"

You should see something like following output:

...
[info] running (fork) com.acmeco.widget.WidgetTeamServer 
[info] 2023-09-07 13:53:47,669 INFO  akka.event.slf4j.Slf4jLogger [] - Slf4jLogger started
[info] (gRPC server bound to {}:{},127.0.0.1,8080)
  • Note the gRPC server bound above, showing the server successfully started

Running the Client

To run the client, execute the following in a separate terminal window:

prompt> sbt "runMain com.acmeco.widget.WidgetTeamClient"

Upon running the client, you should see something like:

prompt> sbt "runMain com.acmeco.widget.WidgetTeamClient"
[info] welcome to sbt 1.9.3 (Eclipse Adoptium Java 11.0.20.1)
[info] loading settings for project acmeco-widget-build-build-build from metals.sbt ...
[info] loading project definition from /Users/duncan/Code/acmeco-widget/project/project/project
[info] loading settings for project acmeco-widget-build-build from metals.sbt ...
[info] loading project definition from /Users/duncan/Code/acmeco-widget/project/project
[success] Generated .bloop/acmeco-widget-build-build.json
[success] Total time: 0 s, completed Oct 2, 2023, 5:25:42 PM
[info] loading settings for project acmeco-widget-build from metals.sbt,plugins.sbt ...
[info] loading project definition from /Users/duncan/Code/acmeco-widget/project
[success] Generated .bloop/acmeco-widget-build.json
[success] Total time: 0 s, completed Oct 2, 2023, 5:25:42 PM
[info] loading settings for project acmeco-widget from build.sbt ...
[info] set current project to acmeco-widget (in build file:/Users/duncan/Code/acmeco-widget/)
[info] running (fork) com.acmeco.widget.WidgetTeamClient 
[info] 2023-10-02 17:25:44,328 INFO  akka.event.slf4j.Slf4jLogger [] - Slf4jLogger started

and then this (the create, read, update and delete actions firing):

[info] Create Response: CreateWidgetTeamResponse(Some(WidgetTeam(3,Widget Team 3,,,None,,UnknownFieldSet(Map()))),UnknownFieldSet(Map()))
[info] Read All Response: ReadAllWidgetTeamsResponse(Vector(WidgetTeam(1,Widget Team 1,,,None,,UnknownFieldSet(Map())), WidgetTeam(2,Widget Team 2,,,None,,UnknownFieldSet(Map()))),UnknownFieldSet(Map()))
[info] Read All Response: ReadAllWidgetTeamsResponse(Vector(WidgetTeam(1,Widget Team 1,,,None,,UnknownFieldSet(Map())), WidgetTeam(2,Widget Team 2,,,None,,UnknownFieldSet(Map())), WidgetTeam(3,Widget Team 3,,,None,,UnknownFieldSet(Map()))),UnknownFieldSet(Map()))
[info] Read Response: ReadWidgetTeamResponse(Some(WidgetTeam(3,Widget Team 3,,,None,,UnknownFieldSet(Map()))),UnknownFieldSet(Map()))
[info] Update Response: UpdateWidgetTeamResponse(Some(WidgetTeam(3,Widget Team 3 UPDATED,,,None,,UnknownFieldSet(Map()))),UnknownFieldSet(Map()))
[info] Read All Response: ReadAllWidgetTeamsResponse(Vector(WidgetTeam(1,Widget Team 1,,,None,,UnknownFieldSet(Map())), WidgetTeam(2,Widget Team 2,,,None,,UnknownFieldSet(Map())), WidgetTeam(3,Widget Team 3 UPDATED,,,None,,UnknownFieldSet(Map()))),UnknownFieldSet(Map()))
[info] Delete Response: DeleteWidgetTeamResponse(true,3,UnknownFieldSet(Map()))
[info] Read All Response: ReadAllWidgetTeamsResponse(Vector(WidgetTeam(1,Widget Team 1,,,None,,UnknownFieldSet(Map())), WidgetTeam(2,Widget Team 2,,,None,,UnknownFieldSet(Map()))),UnknownFieldSet(Map()))

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Akka gRPC Demo

License:Apache License 2.0

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