├── .gitignore
├── kotlin-grpc-keyvalue-service
    ├── src
    │   └── main
    │   │   ├── java
    │   │       └── grpc
    │   │       │   └── service
    │   │       │       └── kv
    │   │       │           ├── GrpcServer.kt
    │   │       │           └── KeyValueService.kt
    │   │   └── proto
    │   │       └── kv.proto
    └── pom.xml
├── kotlin-grpc-user-service
    ├── src
    │   └── main
    │   │   ├── proto
    │   │       └── user.proto
    │   │   └── java
    │   │       └── grpc
    │   │           └── service
    │   │               └── user
    │   │                   ├── GrpcServer.kt
    │   │                   └── UserService.kt
    └── pom.xml
├── README.md
├── kotlin-grpc-client
    ├── src
    │   └── main
    │   │   └── java
    │   │       └── grpc
    │   │           └── client
    │   │               └── GrpcClient.kt
    └── pom.xml
└── pom.xml


/.gitignore:
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1 | .idea
2 | *.iml
3 | target
4 | 


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/kotlin-grpc-keyvalue-service/src/main/java/grpc/service/kv/GrpcServer.kt:
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 1 | package grpc.service.kv
 2 | 
 3 | fun main(args: Array<String>) {
 4 | 
 5 |     val server = io.grpc.ServerBuilder.forPort(15000).addService(KeyValueService()).build()
 6 |     server.start()
 7 | 
 8 |     println("Key value service started")
 9 | 
10 |     Runtime.getRuntime().addShutdownHook(Thread { println("Ups, JVM shutdown") })
11 |     server.awaitTermination()
12 | 
13 |     println("Key value service stopped")
14 | }
15 | 


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/kotlin-grpc-user-service/src/main/proto/user.proto:
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 1 | syntax = "proto3";
 2 | 
 3 | package services;
 4 | 
 5 | option java_multiple_files = true;
 6 | option java_package = "services";
 7 | option java_outer_classname = "UserServiceProtos";
 8 | 
 9 | service UserService {
10 |     rpc getUser(UserRequest) returns (UserResponse) {}
11 | }
12 | 
13 | // The request message containing the user's name.
14 | message UserRequest {
15 |     string name = 1;
16 | }
17 | 
18 | // The response message containing the greetings
19 | message UserResponse {
20 |     string name = 1;
21 |     string emailAddress = 2;
22 |     bool active = 3;
23 |     string country = 4;
24 | }
25 | 


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/kotlin-grpc-keyvalue-service/src/main/proto/kv.proto:
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 1 | syntax = "proto3";
 2 | 
 3 | package services;
 4 | 
 5 | option java_multiple_files = true;
 6 | option java_package = "services";
 7 | option java_outer_classname = "KeyValueServiceProtos";
 8 | 
 9 | service KeyValueService {
10 |     rpc put(PutRequest) returns (PutResponse) {}
11 |     rpc get(GetRequest) returns (GetResponse) {}
12 | }
13 | 
14 | message PutRequest {
15 |     string key = 1;
16 |     string value = 2;
17 | }
18 | 
19 | message PutResponse {
20 | }
21 | 
22 | message GetRequest {
23 |     string key = 1;
24 | }
25 | 
26 | message GetResponse {
27 |     string key = 1;
28 |     string value = 2;
29 | }
30 | 


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/kotlin-grpc-user-service/src/main/java/grpc/service/user/GrpcServer.kt:
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 1 | package grpc.service.user
 2 | 
 3 | import io.grpc.ManagedChannelBuilder
 4 | import io.grpc.ServerBuilder
 5 | import services.KeyValueServiceGrpcKt
 6 | 
 7 | fun main(args: Array<String>) {
 8 | 
 9 |     val channel = ManagedChannelBuilder.forAddress("localhost", 15000).usePlaintext().build()
10 |     val kvsClient = KeyValueServiceGrpcKt.newStub(channel)
11 | 
12 |     val server = ServerBuilder.forPort(15001).addService(UserService(kvsClient)).build()
13 |     server.start()
14 | 
15 |     println("User service started")
16 | 
17 |     Runtime.getRuntime().addShutdownHook(Thread { println("Ups, JVM shutdown") })
18 |     server.awaitTermination()
19 | 
20 |     println("User service stopped")
21 | }
22 | 


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/README.md:
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 1 | # Simple Sample Kotlin gRPC service
 2 | 
 3 | Very simple Java8 sample of a gRPC Kotlin service.
 4 | Check Java9 branch to check Java9 sample.
 5 | 
 6 | This samples is composed by two gRPC services (user and key value) and one client.
 7 | The user service must get data from the key value service to provide all information about the user to a client.
 8 | 
 9 | 
10 | 
11 | ### Pre requirements
12 | * Java 8
13 | * Maven
14 | 
15 | ### About gRPC
16 | ...
17 | 
18 | ### About Kotlin
19 | ...
20 | 
21 | ## Try it
22 | 
23 | 
24 | **Build**
25 | ```
26 | mvn clean install
27 | ```
28 | ### Run key value service
29 | ```
30 | mvn -pl kotlin-grpc-keyvalue-service exec:java
31 | ```
32 | ### Run user service
33 | ```
34 | mvn -pl kotlin-grpc-user-service exec:java
35 | ```
36 | ### Run the client
37 | ```
38 | mvn -pl kotlin-grpc-client exec:java
39 | ```
40 | 


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/kotlin-grpc-client/src/main/java/grpc/client/GrpcClient.kt:
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 1 | package grpc.client
 2 | 
 3 | import com.google.common.collect.Iterators
 4 | import io.grpc.ManagedChannelBuilder
 5 | import services.UserRequest
 6 | import services.UserServiceGrpc
 7 | import java.util.concurrent.TimeUnit
 8 | 
 9 | fun main(args: Array<String>) {
10 | 
11 |     val channel = ManagedChannelBuilder.forAddress("localhost", 15001).usePlaintext().build()
12 |     val blockingStub = UserServiceGrpc.newBlockingStub(channel)
13 | 
14 |     try {
15 |         val users = Iterators.cycle("radha", "kanti", "chanda", "kali")
16 |         var i = 0
17 |         while (users.hasNext() && i < 100) {
18 | 
19 |             val request = UserRequest.newBuilder().setName(users.next()).build()
20 | 
21 |             println("Response from server:\n${blockingStub.getUser(request)}")
22 |             i++
23 |         }
24 | 
25 |     } finally {
26 |         channel.shutdown().awaitTermination(5, TimeUnit.SECONDS)
27 |     }
28 | }
29 | 


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/kotlin-grpc-user-service/src/main/java/grpc/service/user/UserService.kt:
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 1 | package grpc.service.user
 2 | 
 3 | import kotlinx.coroutines.async
 4 | import services.GetRequest
 5 | import services.KeyValueServiceGrpcKt.KeyValueServiceKtStub
 6 | import services.UserRequest
 7 | import services.UserResponse
 8 | import services.UserServiceGrpcKt.UserServiceImplBase
 9 | 
10 | class UserService(private val keyValue: KeyValueServiceKtStub) : UserServiceImplBase() {
11 | 
12 |     override suspend fun getUser(request: UserRequest): UserResponse {
13 |         suspend fun getValue(key: String) = keyValue.get(
14 |                 GetRequest
15 |                         .newBuilder()
16 |                         .setKey(request.name + key)
17 |                         .build() ?: throw IllegalArgumentException("key not found")
18 |         )
19 | 
20 |         val email = async { getValue(".email") }
21 |         val country = async { getValue(".country") }
22 |         val active = async { getValue(".active") }
23 | 
24 |         return UserResponse
25 |                 .newBuilder()
26 |                 .setName(request.name ?: throw IllegalArgumentException("name can not be null"))
27 |                 .setEmailAddress(email.await().value)
28 |                 .setCountry(country.await().value)
29 |                 .setActive(active.await().value?.toBoolean() ?: false)
30 |                 .build()
31 |     }
32 | 
33 | }
34 | 


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/kotlin-grpc-keyvalue-service/pom.xml:
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 1 | <?xml version="1.0" encoding="UTF-8"?>
 2 | <project xmlns="http://maven.apache.org/POM/4.0.0"
 3 |          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4 |          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 5 |     <parent>
 6 |         <artifactId>kotlin-grpc-sample</artifactId>
 7 |         <groupId>flaviof.samples.kotlin</groupId>
 8 |         <version>1.0-SNAPSHOT</version>
 9 |     </parent>
10 |     <modelVersion>4.0.0</modelVersion>
11 | 
12 |     <artifactId>kotlin-grpc-keyvalue-service</artifactId>
13 | 
14 |     <dependencies>
15 |         <dependency>
16 |             <groupId>io.grpc</groupId>
17 |             <artifactId>grpc-all</artifactId>
18 |         </dependency>
19 |     </dependencies>
20 | 
21 |     <build>
22 |         <plugins>
23 |             <plugin>
24 |                 <groupId>org.codehaus.mojo</groupId>
25 |                 <artifactId>exec-maven-plugin</artifactId>
26 |                 <version>1.2.1</version>
27 |                 <executions>
28 |                     <execution>
29 |                         <goals>
30 |                             <goal>java</goal>
31 |                         </goals>
32 |                     </execution>
33 |                 </executions>
34 |                 <configuration>
35 |                     <mainClass>grpc.service.kv.GrpcServerKt</mainClass>
36 |                 </configuration>
37 |             </plugin>
38 |         </plugins>
39 |     </build>
40 | 
41 | </project>
42 | 


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/kotlin-grpc-client/pom.xml:
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 1 | <?xml version="1.0" encoding="UTF-8"?>
 2 | <project xmlns="http://maven.apache.org/POM/4.0.0"
 3 |          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4 |          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 5 |     <parent>
 6 |         <artifactId>kotlin-grpc-sample</artifactId>
 7 |         <groupId>flaviof.samples.kotlin</groupId>
 8 |         <version>1.0-SNAPSHOT</version>
 9 |     </parent>
10 |     <modelVersion>4.0.0</modelVersion>
11 | 
12 |     <artifactId>kotlin-grpc-client</artifactId>
13 | 
14 |     <dependencies>
15 |         <dependency>
16 |             <groupId>flaviof.samples.kotlin</groupId>
17 |             <artifactId>kotlin-grpc-user-service</artifactId>
18 |             <version>1.0-SNAPSHOT</version>
19 |         </dependency>
20 | 
21 |         <dependency>
22 |             <groupId>io.grpc</groupId>
23 |             <artifactId>grpc-all</artifactId>
24 |         </dependency>
25 |     </dependencies>
26 | 
27 |     <build>
28 |         <plugins>
29 |             <plugin>
30 |                 <groupId>org.codehaus.mojo</groupId>
31 |                 <artifactId>exec-maven-plugin</artifactId>
32 |                 <version>1.2.1</version>
33 |                 <executions>
34 |                     <execution>
35 |                         <goals>
36 |                             <goal>java</goal>
37 |                         </goals>
38 |                     </execution>
39 |                 </executions>
40 |                 <configuration>
41 |                     <mainClass>grpc.client.GrpcClientKt</mainClass>
42 |                 </configuration>
43 |             </plugin>
44 |         </plugins>
45 |     </build>
46 | 
47 | </project>
48 | 


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/kotlin-grpc-user-service/pom.xml:
--------------------------------------------------------------------------------
 1 | <?xml version="1.0" encoding="UTF-8"?>
 2 | <project xmlns="http://maven.apache.org/POM/4.0.0"
 3 |          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4 |          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 5 |     <parent>
 6 |         <artifactId>kotlin-grpc-sample</artifactId>
 7 |         <groupId>flaviof.samples.kotlin</groupId>
 8 |         <version>1.0-SNAPSHOT</version>
 9 |     </parent>
10 |     <modelVersion>4.0.0</modelVersion>
11 | 
12 |     <artifactId>kotlin-grpc-user-service</artifactId>
13 | 
14 |     <dependencies>
15 |         <dependency>
16 |             <groupId>flaviof.samples.kotlin</groupId>
17 |             <artifactId>kotlin-grpc-keyvalue-service</artifactId>
18 |             <version>1.0-SNAPSHOT</version>
19 |         </dependency>
20 | 
21 |         <dependency>
22 |             <groupId>io.grpc</groupId>
23 |             <artifactId>grpc-all</artifactId>
24 |         </dependency>
25 |     </dependencies>
26 | 
27 |     <build>
28 |         <plugins>
29 |             <plugin>
30 |                 <groupId>org.codehaus.mojo</groupId>
31 |                 <artifactId>exec-maven-plugin</artifactId>
32 |                 <version>1.2.1</version>
33 |                 <executions>
34 |                     <execution>
35 |                         <goals>
36 |                             <goal>java</goal>
37 |                         </goals>
38 |                     </execution>
39 |                 </executions>
40 |                 <configuration>
41 |                     <mainClass>grpc.service.user.GrpcServerKt</mainClass>
42 |                 </configuration>
43 |             </plugin>
44 |         </plugins>
45 |     </build>
46 | 
47 | </project>
48 | 


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/kotlin-grpc-keyvalue-service/src/main/java/grpc/service/kv/KeyValueService.kt:
--------------------------------------------------------------------------------
 1 | package grpc.service.kv
 2 | 
 3 | import services.GetRequest
 4 | import services.GetResponse
 5 | import services.KeyValueServiceGrpcKt.KeyValueServiceImplBase
 6 | import services.PutRequest
 7 | import services.PutResponse
 8 | 
 9 | class KeyValueService : KeyValueServiceImplBase() {
10 | 
11 |     val names = listOf("radha", "kanti", "chanda", "kali")
12 | 
13 |     internal var store: MutableMap<String, String> = hashMapOf(
14 |             "${names[0]}.email" to "${names[0]}@gmail.com",
15 |             "${names[0]}.country" to "Portugal",
16 |             "${names[0]}.active" to "true",
17 |             "${names[1]}.email" to "${names[1]}@gmail.com",
18 |             "${names[1]}.country" to "France",
19 |             "${names[1]}.active" to "true",
20 |             "${names[2]}.email" to "${names[2]}@gmail.com",
21 |             "${names[2]}.country" to "Spain",
22 |             "${names[2]}.active" to "true",
23 |             "${names[3]}.email" to "${names[3]}@gmail.com",
24 |             "${names[3]}.country" to "UK",
25 |             "${names[3]}.active" to "false"
26 |     )
27 | 
28 |     override suspend fun put(request: PutRequest): PutResponse {
29 |         store.put(request.key ?: throw IllegalArgumentException("key can not be null"),
30 |             request.value ?: throw IllegalArgumentException("value can not be null")
31 |         )
32 | 
33 |         return PutResponse.getDefaultInstance()
34 |     }
35 | 
36 |     override suspend fun get(request: GetRequest): GetResponse {
37 |         return GetResponse
38 |                 .newBuilder()
39 |                 .setValue(
40 |                         store[request.key ?: throw IllegalArgumentException("key can not be null")]
41 |                                 ?: throw IllegalArgumentException("${request.key} key not found")
42 |                 ).build()
43 |     }
44 | 
45 | }
46 | 


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/pom.xml:
--------------------------------------------------------------------------------
  1 | <?xml version="1.0" encoding="UTF-8"?>
  2 | <project xmlns="http://maven.apache.org/POM/4.0.0"
  3 |          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  4 |          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  5 |     <modelVersion>4.0.0</modelVersion>
  6 | 
  7 |     <groupId>flaviof.samples.kotlin</groupId>
  8 |     <artifactId>kotlin-grpc-sample</artifactId>
  9 |     <packaging>pom</packaging>
 10 |     <version>1.0-SNAPSHOT</version>
 11 | 
 12 |     <modules>
 13 |         <module>kotlin-grpc-user-service</module>
 14 |         <module>kotlin-grpc-keyvalue-service</module>
 15 |         <module>kotlin-grpc-client</module>
 16 |     </modules>
 17 | 
 18 |     <properties>
 19 |         <kotlin.version>1.3.0</kotlin.version>
 20 | 
 21 |         <grpc.version>1.16.1</grpc.version>
 22 |         <protobuf.version>3.5.1-1</protobuf.version>
 23 |     </properties>
 24 | 
 25 |     <dependencyManagement>
 26 |         <dependencies>
 27 |             <dependency>
 28 |                 <groupId>io.grpc</groupId>
 29 |                 <artifactId>grpc-all</artifactId>
 30 |                 <version>${grpc.version}</version>
 31 |             </dependency>
 32 | 
 33 |             <dependency>
 34 |                 <groupId>org.jetbrains.kotlin</groupId>
 35 |                 <artifactId>kotlin-stdlib</artifactId>
 36 |                 <version>${kotlin.version}</version>
 37 |             </dependency>
 38 |             <dependency>
 39 |                 <groupId>org.jetbrains.kotlinx</groupId>
 40 |                 <artifactId>kotlinx-coroutines-core</artifactId>
 41 |                 <version>1.0.0</version>
 42 |             </dependency>
 43 |             <dependency>
 44 |                 <groupId>org.jetbrains.kotlin</groupId>
 45 |                 <artifactId>kotlin-test-junit</artifactId>
 46 |                 <version>${kotlin.version}</version>
 47 |             </dependency>
 48 |         </dependencies>
 49 |     </dependencyManagement>
 50 | 
 51 |     <dependencies>
 52 |         <dependency>
 53 |             <groupId>org.jetbrains.kotlin</groupId>
 54 |             <artifactId>kotlin-stdlib</artifactId>
 55 |         </dependency>
 56 | 
 57 |         <dependency>
 58 |             <groupId>org.jetbrains.kotlinx</groupId>
 59 |             <artifactId>kotlinx-coroutines-core</artifactId>
 60 |         </dependency>
 61 |         <dependency>
 62 |             <groupId>org.jetbrains.kotlin</groupId>
 63 |             <artifactId>kotlin-test-junit</artifactId>
 64 |             <scope>test</scope>
 65 |         </dependency>
 66 |     </dependencies>
 67 | 
 68 |     <build>
 69 |         <extensions>
 70 |             <extension>
 71 |                 <groupId>kr.motd.maven</groupId>
 72 |                 <artifactId>os-maven-plugin</artifactId>
 73 |                 <version>1.4.1.Final</version>
 74 |             </extension>
 75 |         </extensions>
 76 |         <plugins>
 77 |             <plugin>
 78 |                 <artifactId>maven-compiler-plugin</artifactId>
 79 |                 <configuration>
 80 |                     <source>1.8</source>
 81 |                     <target>1.8</target>
 82 |                 </configuration>
 83 |             </plugin>
 84 |             <plugin>
 85 |                 <groupId>org.jetbrains.kotlin</groupId>
 86 |                 <artifactId>kotlin-maven-plugin</artifactId>
 87 |                 <version>${kotlin.version}</version>
 88 |                 <executions>
 89 |                     <execution>
 90 |                         <id>compile</id>
 91 |                         <phase>compile</phase>
 92 |                         <goals>
 93 |                             <goal>compile</goal>
 94 |                         </goals>
 95 |                     </execution>
 96 |                     <execution>
 97 |                         <id>test-compile</id>
 98 |                         <phase>test-compile</phase>
 99 |                         <goals>
100 |                             <goal>test-compile</goal>
101 |                         </goals>
102 |                     </execution>
103 |                 </executions>
104 |             </plugin>
105 |             <plugin>
106 |                 <groupId>org.xolstice.maven.plugins</groupId>
107 |                 <artifactId>protobuf-maven-plugin</artifactId>
108 |                 <version>0.5.0</version>
109 |                 <configuration>
110 |                     <protocArtifact>com.google.protobuf:protoc:${protobuf.version}:exe:${os.detected.classifier}</protocArtifact>
111 |                     <pluginId>grpc-java</pluginId>
112 |                     <pluginArtifact>io.grpc:protoc-gen-grpc-java:${grpc.version}:exe:${os.detected.classifier}</pluginArtifact>
113 |                     <protocPlugins>
114 |                         <protocPlugin>
115 |                             <id>GrpcKotlinGenerator</id>
116 |                             <groupId>io.rouz</groupId>
117 |                             <artifactId>grpc-kotlin-gen</artifactId>
118 |                             <version>0.0.6</version>
119 |                             <mainClass>io.rouz.grpc.kotlin.GrpcKotlinGenerator</mainClass>
120 |                         </protocPlugin>
121 |                     </protocPlugins>
122 |                 </configuration>
123 |                 <executions>
124 |                     <execution>
125 |                         <goals>
126 |                             <goal>compile</goal>
127 |                             <goal>compile-custom</goal>
128 |                         </goals>
129 |                     </execution>
130 |                 </executions>
131 |             </plugin>
132 |         </plugins>
133 |     </build>
134 | 
135 | </project>
136 | 


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