Refactoring to batch (#181)

The rationale of this pull request is to

* have more maintainable and granular code
* not maintain the custom made job engine
* allow the users to customize the defaults of the releaser more easy
* allow the users to create their own steps without the need to change any existing code
* allow the users to fully change the flows and tasks logic
* abstract underlying batch mechanism (Spring Batch) so it doesn't leak to production code
* allow parallelization of the release process and release tasks

projects/spring-cloud-stream/src/main/java/releaser/ReleaserApplication.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2013-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package releaser;
+
+import releaser.internal.options.Parser;
+import releaser.internal.spring.ExecutionResultHandler;
+import releaser.internal.spring.SpringReleaser;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.WebApplicationType;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class ReleaserApplication extends ReleaserCommandLineRunner {
+
+	public ReleaserApplication(SpringReleaser releaser,
+			ExecutionResultHandler executionResultHandler, Parser parser) {
+		super(releaser, executionResultHandler, parser);
+	}
+
+	public static void main(String[] args) {
+		SpringApplication application = new SpringApplication(ReleaserApplication.class);
+		application.setWebApplicationType(WebApplicationType.NONE);
+		application.run(args);
+	}
+
+}

projects/spring-cloud-stream/src/main/resources/application.yml

@@ -0,0 +1,42 @@
+spring:
+  main:
+    web-application-type: none
+  datasource:
+    url: jdbc:h2:mem:${random.uuid}
+  jackson:
+    deserialization:
+      FAIL_ON_UNKNOWN_PROPERTIES: true
+releaser:
+  git:
+    release-train-bom-url: https://github.com/spring-cloud/spring-cloud-stream-starters
+    documentation-url: https://github.com/spring-cloud/spring-cloud-static
+    number-of-checked-milestones: 50
+    update-github-milestones: true
+  pom:
+    branch: master
+    pom-with-boot-starter-parent: spring-cloud-starter-parent/pom.xml
+    this-train-bom: spring-cloud-stream-dependencies/pom.xml
+    bom-version-pattern: "^(spring-cloud-.*)\\.version$"
+    ignored-pom-regex:
+      - "^.*\\.git/.*$"
+  maven:
+    build-command: "./mvnw clean install -B -Pdocs {{systemProps}}"
+    deploy-command: "./mvnw deploy -DskipTests -B -Pfast,deploy {{systemProps}}"
+    deploy-guides-command: "./mvnw clean verify deploy -B -Pguides,integration -pl guides {{systemProps}}"
+    publish-docs-commands:
+      - "mkdir -p target"
+      - "wget https://raw.githubusercontent.com/spring-cloud/spring-cloud-build/master/docs/src/main/asciidoc/ghpages.sh -O target/gh-pages.sh"
+      - "chmod +x target/gh-pages.sh"
+      - "./target/gh-pages.sh -v {{version}} -c"
+    generate-release-train-docs-command: "bash release_train.sh --retrieveversions --version {{version}} --ghpages --auto"
+  sagan:
+    update-sagan: true
+  meta-release:
+    release-train-project-name: spring-cloud-stream-starters
+    release-train-dependency-names:
+      - spring-cloud-stream-dependencies
+    git-org-url: https://github.com/spring-cloud
+    projects-to-skip:
+      - spring-boot
+      - spring-cloud-build
+      - spring-cloud-function

projects/spring-cloud-stream/src/test/java/releaser/ReleaserApplicationTests.java

@@ -0,0 +1,59 @@
+/*
+ * Copyright 2013-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package releaser;
+
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+import releaser.internal.options.Parser;
+import releaser.internal.spring.ExecutionResultHandler;
+import releaser.internal.spring.SpringReleaser;
+
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@SpringBootTest(
+		classes = { ReleaserApplicationTests.Config.class, ReleaserApplication.class },
+		properties = { "releaser.sagan.update-sagan=false" })
+class ReleaserApplicationTests {
+
+	@Test
+	void contextLoads() {
+
+	}
+
+	@Configuration
+	static class Config {
+
+		@Bean
+		SpringReleaser mockReleaser() {
+			return Mockito.mock(SpringReleaser.class);
+		}
+
+		@Bean
+		ExecutionResultHandler mockExecutionResultHandler() {
+			return Mockito.mock(ExecutionResultHandler.class);
+		}
+
+		@Bean
+		Parser mockParser() {
+			return Mockito.mock(Parser.class);
+		}
+
+	}
+
+}