CDC - Pact:Broker Basic

The Pact Broker is an application for sharing for consumer driven contracts and verification results.

• The consumer CI build generates the pacts during execution of its isolated tests, and then publishes the generated pacts.
• The provider CI retrieves the pacts, performs the verification locally, and then publishes the verification results back to the broker.
• Consumer and provider CI deployment builds check with the broker before deploying to ensure the application version they are about deploy will be compatible with the versions of the other applications that are already in that environment.

We can use many approaches to deposite pact files and verification results, i use docker as an example,

Docker Setup

Get info from pact_broker-docker.

1. Install docker.

2. Download docker-compose.yml and modify.

   version: "3"
   
   services:  postgres:    image: postgres    healthcheck:      test: psql postgres --command "select 1" -U postgres    ports:      - "5432:5432"    environment:      POSTGRES_USER: postgres      POSTGRES_PASSWORD: password      POSTGRES_DB: postgres  broker_app:    image: dius/pact-broker    links:      - postgres    # If you remove nginx, enable the following    ports:      - "80:80"    environment:      PACT_BROKER_DATABASE_USERNAME: postgres      PACT_BROKER_DATABASE_PASSWORD: password      PACT_BROKER_DATABASE_HOST: postgres      PACT_BROKER_DATABASE_NAME: postgres
     postgres:
       image: postgres
       healthcheck:
         test: psql postgres --command "select 1" -U postgres
       ports:
         - "5432:5432"
       environment:
         POSTGRES_USER: postgres
         POSTGRES_PASSWORD: password
         POSTGRES_DB: postgres
   
     broker_app:
       image: dius/pact-broker
       links:
         - postgres
       # If you remove nginx, enable the following
       ports:
         - "80:80"
       environment:
         PACT_BROKER_DATABASE_USERNAME: postgres
         PACT_BROKER_DATABASE_PASSWORD: password
         PACT_BROKER_DATABASE_HOST: postgres
         PACT_BROKER_DATABASE_NAME: postgres

3. Run docker-compose up command to get a running Pact Broker and a clean Postgres database.

4. Verify.
   

Pact Broker Usage

consumer

1. Add the below configs in consumer pom.

   <plugin>
     <!-- mvn pact:publish  -->
     <groupId>au.com.dius</groupId>
     <artifactId>pact-jvm-provider-maven_2.11</artifactId>
     <version>3.5.24</version>
     <configuration>
       <!-- <pactDirectory>../pacts</pactDirectory> Defaults to ${project.build.directory}/pacts -->
       <pactBrokerUrl>http://192.168.220.139:80</pactBrokerUrl>
       <projectVersion>${project.version}</projectVersion> <!-- Defaults to ${project.version} -->
       <trimSnapshot>true</trimSnapshot> <!-- Defaults to false -->
       <tags>
           <tag>cdc/pact_broker</tag>
         </tags>
     </configuration>
   </plugin>

2. execute mvn pact:publish to publish the pact files.
   

provider

1. Add the below configs in provider pom.

    <plugin>
       <groupId>au.com.dius</groupId>
       <artifactId>pact-jvm-provider-maven_2.12</artifactId>
       <version>3.5.24</version>
       <configuration>
         <serviceProviders>
           <!-- You can define as many as you need, but each must have a unique name -->
           <serviceProvider>
             <name>test_provider</name>
             <!-- All the provider properties are optional, and have sensible defaults (shown below) -->
             <protocol>http</protocol>
             <host>localhost</host>
             <port>8080</port>
             <path>/</path>
             <pactBrokerUrl>http://192.168.220.139:80/</pactBrokerUrl>
           </serviceProvider>
         </serviceProviders>
       </configuration>
   </plugin>

2. Execute mvn pact:verify

   D:\Java\pact\pact-jvm\pact-provider>mvn pact:verify
   [INFO] Scanning for projects...
   [INFO]
   [INFO] ----------------------< com.izheyi:pact-provider >----------------------
   [INFO] Building pact-provider 0.0.1-SNAPSHOT
   [INFO] --------------------------------[ jar ]---------------------------------
   [INFO]
   [INFO] --- pact-jvm-provider-maven_2.12:3.5.24:verify (default-cli) @ pact-provider ---
   
   Verifying a pact between test_consumer and test_provider
     [from Pact Broker http://192.168.220.139/pacts/provider/test_provider/consumer/test_consumer/version/0.0.1]
     A request for age for person zhangsan
       returns a response which
         has status code 200 (OK)
         includes headers
           "Content-Type" with value "application/json" (OK)
         has a matching body (OK)
   [WARNING] Skipping publishing of verification results as it has been disabled (pact.verifier.publishResults is not 'true')
   [INFO] ------------------------------------------------------------------------
   [INFO] BUILD SUCCESS
   [INFO] ------------------------------------------------------------------------
   [INFO] Total time:  6.702 s
   [INFO] Finished at: 2018-11-18T13:12:24+08:00
   [INFO] ------------------------------------------------------------------------

3. We can see there has one WARNING, Publishing of verification results will be skipped unless this property is set to ‘true’, so we need to add the below config.

   <configuration>
   	<pact.verifier.publishResults>true</pact.verifier.publishResults>
   </configuration>

4. Execute mvn pact:verify again.