Convert generate script to gradle task (#8)

README.md

@@ -3,3 +3,16 @@
 # OpenTelemetry Semantic Conventions for Java
 
 Java code-generation for the [OpenTelemetry Semantic Conventions](https://github.com/open-telemetry/semantic-conventions).
+
+## Generating semantic conventions
+
+Prerequisites:
+- Docker
+- JDK 17+
+
+In a shell, execute the following gradle tasks:
+
+```shell
+./gradlew generateSemanticConventions --console=plain
+./gradlew spotlessApply
+```

build.gradle.kts

@@ -1,7 +1,11 @@
+import de.undercouch.gradle.tasks.download.Download
+
 plugins {
   id("otel.java-conventions")
 
   id("otel.animalsniffer-conventions")
+
+  id("de.undercouch.download")
 }
 
 dependencies {
@@ -15,3 +19,75 @@ dependencies {
   testImplementation(platform("org.assertj:assertj-bom:3.24.2"))
   testImplementation("org.assertj:assertj-core")
 }
+
+val specificationVersion = "1.20.0"
+var generatorVersion = "0.18.0"
+
+val specificationRepoZip = "https://github.com/open-telemetry/opentelemetry-specification/archive/v$specificationVersion.zip"
+val schemaUrl = "https://opentelemetry.io/schemas/$specificationVersion"
+
+val downloadSpecification by tasks.registering(Download::class) {
+  src(specificationRepoZip)
+  dest("$buildDir/opentelemetry-specification/opentelemetry-specification.zip")
+  overwrite(false)
+}
+
+val unzipConfigurationSchema by tasks.registering(Copy::class) {
+  dependsOn(downloadSpecification)
+
+  from(zipTree(downloadSpecification.get().dest))
+  eachFile(closureOf<FileCopyDetails> {
+    // Remove the top level folder "/opentelemetry-specification-$semanticConventionsVersion"
+    val pathParts = path.split("/")
+    path = pathParts.subList(1, pathParts.size).joinToString("/")
+  })
+  into("$buildDir/opentelemetry-specification/")
+}
+
+val generateSemanticAttributes by tasks.registering(Exec::class) {
+  dependsOn(unzipConfigurationSchema)
+
+  standardOutput = System.out
+  executable = "docker"
+  setArgs(listOf(
+    "run",
+    "--rm",
+    "-v", "$buildDir/opentelemetry-specification/semantic_conventions:/source",
+    "-v", "$projectDir/buildscripts/templates:/templates",
+    "-v", "$projectDir/src/main/java/io/opentelemetry/semconv/trace/attributes/:/output",
+    "otel/semconvgen:$generatorVersion",
+    "--only", "span,event,attribute_group,scope",
+    "-f", "/source", "code",
+    "--template", "/templates/SemanticAttributes.java.j2",
+    "--output", "/output/SemanticAttributes.java",
+    "-Dsemconv=trace",
+    "-Dclass=SemanticAttributes",
+    "-DschemaUrl=$schemaUrl",
+    "-Dpkg=io.opentelemetry.semconv.trace.attributes"))
+}
+
+val generateResourceAttributes by tasks.registering(Exec::class) {
+  dependsOn(unzipConfigurationSchema)
+
+  standardOutput = System.out
+  executable = "docker"
+  setArgs(listOf(
+    "run",
+    "--rm",
+    "-v", "$buildDir/opentelemetry-specification/semantic_conventions:/source",
+    "-v", "$projectDir/buildscripts/templates:/templates",
+    "-v", "$projectDir/src/main/java/io/opentelemetry/semconv/resource/attributes/:/output",
+    "otel/semconvgen:$generatorVersion",
+    "--only", "resource",
+    "-f", "/source", "code",
+    "--template", "/templates/SemanticAttributes.java.j2",
+    "--output", "/output/ResourceAttributes.java",
+    "-Dclass=ResourceAttributes",
+    "-DschemaUrl=$schemaUrl",
+    "-Dpkg=io.opentelemetry.semconv.resource.attributes"))
+}
+
+val generateSemanticConventions by tasks.registering {
+  dependsOn(generateSemanticAttributes)
+  dependsOn(generateResourceAttributes)
+}

settings.gradle.kts

@@ -1,6 +1,7 @@
 pluginManagement {
   plugins {
     id("com.gradle.enterprise") version "3.14.1"
+    id("de.undercouch.download") version "5.4.0"
   }
 }