Added automated configprops table generation; fixes gh-144

docs/src/main/asciidoc/README.adoc

@@ -68,13 +68,17 @@ approach of generating documentation just add these plugins to your `docs` modul
 						<groupId>org.apache.maven.plugins</groupId>
 						<artifactId>maven-resources-plugin</artifactId> <3>
 					</plugin>
+					<plugin>
+						<groupId>org.codehaus.mojo</groupId>
+						<artifactId>exec-maven-plugin</artifactId> <4>
+					</plugin>
 					<plugin>
 						<groupId>org.asciidoctor</groupId>
-						<artifactId>asciidoctor-maven-plugin</artifactId> <4>
+						<artifactId>asciidoctor-maven-plugin</artifactId> <5>
 					</plugin>
 					<plugin>
 						<groupId>org.apache.maven.plugins</groupId>
-						<artifactId>maven-antrun-plugin</artifactId> <5>
+						<artifactId>maven-antrun-plugin</artifactId> <6>
 					</plugin>
 				</plugins>
 			</build>
@@ -84,11 +88,14 @@ approach of generating documentation just add these plugins to your `docs` modul
 <2> This plugin downloads sets up all the git information of the project
 <2> This plugin downloads the resources of the `spring-cloud-build-docs` module
 <3> This plugin unpacks the resources of the `spring-cloud-build-docs` module
-<4> This plugin is required to parse the Asciidoctor documentation
-<5> This plugin is required to copy resources into proper final destinations and to generate main README.adoc and to assert that no files use unresolved links
+<4> This plugin generates an `adoc` file with all the configuration properties from the classpath
+<5> This plugin is required to parse the Asciidoctor documentation
+<6> This plugin is required to copy resources into proper final destinations and to generate main README.adoc and to assert that no files use unresolved links
 
 IMPORTANT: The order of plugin declaration is important!
 
+In order for the build to generate the `adoc` file with all your configuration properties, your `docs` module should contain all the dependencies on the classpath, that you would want to scan for configuration properties. The file will be output to `${docsModule}/src/main/asciidoc/configprops.adoc` file.
+
 Spring Cloud Build Docs comes with a set of attributes for asciidoctor that you can reuse.
 
 [source,xml]

docs/src/main/groovy/org/springframework/cloud/internal/Main.groovy

@@ -0,0 +1,79 @@
+package org.springframework.cloud.internal
+
+import groovy.json.JsonSlurper
+import groovy.transform.CompileStatic
+
+import org.springframework.core.io.Resource
+import org.springframework.core.io.support.PathMatchingResourcePatternResolver
+
+/**
+ * @author Marcin Grzejszczak
+ */
+class Main {
+
+	@CompileStatic
+	static void main(String... args) {
+		String outputFile = args[0]
+		new Main().generate(outputFile)
+	}
+
+	void generate(String outputFile) {
+		println "Parsing all configuration metadata"
+		Resource[] resources = new PathMatchingResourcePatternResolver()
+				.getResources("classpath*:/META-INF/spring-configuration-metadata.json")
+		println "Found [${resources.length}] configuration metadata jsons"
+		TreeSet names = new TreeSet()
+		def descriptions = [:]
+		int count = 0
+		resources.each { Resource resource ->
+			if (resource.url.toString().contains("cloud")) {
+				count++
+				def slurper = new JsonSlurper()
+				slurper.parseText(resource.inputStream.text).properties.each { val ->
+					names.add val.name
+					descriptions[val.name] = new ConfigValue(val.name, val.description, val.defaultValue)
+				}
+			}
+		}
+		println "Found [${count}] Cloud projects configuration metadata jsons"
+		println "Successfully built the description table"
+		if (names.empty) {
+			println("Will not update the table, since no configuration properties were found!")
+			return
+		}
+		new File(outputFile).text = """\
+|===
+|Name | Default | Description
+${names.collect { it -> return descriptions[it] }.join("\n")}
+
+
+
+|===
+"""
+		println "Successfully stored the output file"
+	}
+
+	@CompileStatic
+	static class ConfigValue {
+		String name
+		String description
+		Object defaultValue
+
+		ConfigValue() {}
+
+		ConfigValue(String name, String description, Object defaultValue) {
+			this.name = name
+			this.description = escapedValue(description)
+			this.defaultValue = escapedValue(defaultValue)
+		}
+
+		private String escapedValue(Object value) {
+			return value != null ?
+					value.toString().replaceAll('\\|', '\\\\|') : ''
+		}
+
+		String toString() {
+			"|${name} | ${defaultValue} | ${description}"
+		}
+	}
+}