Change template processor

Author: philmtd

docs/chapters/ABOUT_ONEKO.md

@@ -53,7 +53,7 @@ feature/my-new-feature").
 ### Configuration template
 
 A configuration template is a native Helm values .yaml file (e.g. a service definition).
-Variable placeholders like `${MY_VARIABLE_NAME}` can be used to insert O-Neko specific variables into these templates.
+Variable placeholders like `{{MY_VARIABLE_NAME}}` can be used to insert O-Neko specific variables into these templates.
 The variables can be overridden in project versions to e.g. achieve slightly different configurations of versions without
 having to modify the templates per version.
 

docs/chapters/GETTING_STARTED.md

@@ -45,7 +45,7 @@ chart version. Then you can write your Helm values .yaml file in the editor.
 In order to deploy everything correctly, you need to replace some fixed entries in your files with a template variable syntax.
 The most important is the docker image tag in your deployment.
 
-First and most importantly: You need to set your docker image tag to `${VERSION_NAME}`.
+First and most importantly: You need to set your docker image tag to `{{VERSION_NAME}}`.
 
 `VERSION_NAME` will be replaced with the docker tag you want to deploy, which might be `latest`, `1.0.0`, `bugfix_user_auth`
 or basically every docker tag that exists in your project.
@@ -56,10 +56,10 @@ the cluster to pull your image every time. If your Helm chart does not allow to
 extend your Helm chart.
 
 In order to get dynamic URLs to your app you'll have to configure the host name (e.g. in an ingress).
-In this template you should replace the host string with a string that contains the variable `${SAFE_VERSION_NAME}`, like this:
+In this template you should replace the host string with a string that contains the variable `{{SAFE_VERSION_NAME}}`, like this:
 
 ```yaml
-- host: my_app-${SAFE_VERSION_NAME}.my-k8s-cluster.my-company.com
+- host: my_app-{{SAFE_VERSION_NAME}}.my-k8s-cluster.my-company.com
 ```
 
 `SAFE_VERSION_NAME` should be used, because this will make sure that the string replaced there will result in a valid URL.

pom.xml

@@ -187,6 +187,11 @@
 			<version>3.18.1</version>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>io.marioslab.basis</groupId>
+			<artifactId>template</artifactId>
+			<version>1.7</version>
+		</dependency>
 	</dependencies>
 
 	<build>

src/main/java/io/oneko/project/ProjectVersion.java

@@ -8,9 +8,12 @@
 import java.util.UUID;
 import java.util.stream.Collectors;
 
-import org.apache.commons.lang.StringUtils;
+import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.text.StringSubstitutor;
 
+import io.marioslab.basis.template.Template;
+import io.marioslab.basis.template.TemplateContext;
+import io.marioslab.basis.template.TemplateLoader;
 import io.oneko.automations.LifetimeBehaviour;
 import io.oneko.deployable.DeploymentBehaviour;
 import io.oneko.kubernetes.deployments.DesiredState;
@@ -113,13 +116,22 @@ default String calculateConfiguration() {
 	 * template or a modified version template and the effective template variables.
 	 */
 	default List<WritableConfigurationTemplate> getCalculatedConfigurationTemplates() {
-		StringSubstitutor sub = new StringSubstitutor(this.calculateEffectiveTemplateVariables());
-
+		final Map<String, String> variables = this.calculateEffectiveTemplateVariables();
 		//somehow java does not properly figure out the list type here
 		final List<ConfigurationTemplate> unifiedTemplates = ConfigurationTemplates.unifyTemplateSets(getProject().getDefaultConfigurationTemplates(), getConfigurationTemplates());
+
+		TemplateContext context = new TemplateContext();
+		variables.forEach(context::set);
+		context.set("fn", TemplateFunctions.class);
+
 		return unifiedTemplates.stream()
 				.map(WritableConfigurationTemplate::clone)
-				.peek(template -> template.setContent(sub.replace(template.getContent())))
+				.peek(template -> {
+					TemplateLoader.MapTemplateLoader loader = new TemplateLoader.MapTemplateLoader();
+					loader.set("tpl", template.getContent());
+					final Template tpl = loader.load("tpl");
+					template.setContent(tpl.render(context));
+				})
 				.collect(Collectors.toList());
 	}
 

src/main/java/io/oneko/project/TemplateFunctions.java

@@ -0,0 +1,42 @@
+package io.oneko.project;
+
+import org.apache.commons.lang3.StringUtils;
+
+import lombok.experimental.UtilityClass;
+
+@UtilityClass
+public class TemplateFunctions {
+
+	public static String lowerCase(String str) {
+		return StringUtils.lowerCase(str);
+	}
+
+	public static String replace(String text, String searchString, String replacement) {
+		return StringUtils.replace(text, searchString, replacement);
+	}
+
+	public static String replace(String text, String searchString, String replacement, int max) {
+		return StringUtils.replace(text, searchString, replacement, max);
+	}
+
+	public static String trim(String str) {
+		return StringUtils.trim(str);
+	}
+
+	public static String upperCase(String str) {
+		return StringUtils.upperCase(str);
+	}
+
+	public static String truncate(String str, int maxWidth) {
+		return StringUtils.truncate(str, maxWidth);
+	}
+
+	public static String removeEnd(final String str, final String remove) {
+		return StringUtils.removeEnd(str, remove);
+	}
+
+	public static String removeStart(final String str, final String remove) {
+		return StringUtils.removeStart(str, remove);
+	}
+
+}

src/test/java/io/oneko/project/ProjectVersionTest.java

@@ -27,8 +27,8 @@ void testCalculateConfiguration() {
 		List<WritableConfigurationTemplate> templates = Collections.singletonList(
 				WritableConfigurationTemplate.builder()
 						.content(
-								"This is a template with implicit variables (${PROJECT_NAME}, ${VERSION_NAME}), " +
-										"default variables (${TEST1}), overwritten default variables (${TEST2}) and child variables (${TEST3})"
+								"This is a template with implicit variables ({{PROJECT_NAME}}, {{VERSION_NAME}}), " +
+										"default variables ({{TEST1}}), overwritten default variables ({{TEST2}}) and child variables ({{TEST3}})"
 						)
 						.id(UUID.randomUUID())
 						.name("name")

src/test/java/io/oneko/project/rest/DeployableConfigurationDTOMapperTest.java

@@ -35,7 +35,7 @@ void configShouldHaveReplacesVariables() {
 				.build();
 		final WritableProjectVersion version = project1.createVersion("Name");
 		version.setConfigurationTemplates(Collections.singletonList(
-				WritableConfigurationTemplate.builder().content("${VAR_1} ${VAR_2}").build()
+				WritableConfigurationTemplate.builder().content("{{VAR_1}} {{VAR_2}}").build()
 		));
 		version.setTemplateVariables(templateVariables);