Extended jinja template to generate template-type semantic attributes.

Signed-off-by: Alexander Wert <alexander.wert@elastic.co>

build.gradle.kts

@@ -66,7 +66,7 @@ dependencies {
 }
 
 // start - define tasks to download, unzip, and generate from opentelemetry/semantic-conventions
-var generatorVersion = "0.18.0"
+var generatorVersion = "0.21.0"
 val semanticConventionsRepoZip = "https://github.com/open-telemetry/semantic-conventions/archive/v$semanticConventionsVersion.zip"
 val schemaUrl = "https://opentelemetry.io/schemas/$semanticConventionsVersion"
 

buildscripts/templates/SemanticAttributes.java.j2

@@ -52,6 +52,9 @@ import static io.opentelemetry.api.common.AttributeKey.longKey;
 import static io.opentelemetry.api.common.AttributeKey.stringKey;
 import static io.opentelemetry.api.common.AttributeKey.stringArrayKey;
 
+import static io.opentelemetry.semconv.AttributeKeyTemplate.stringArrayKeyTemplate;
+import static io.opentelemetry.semconv.AttributeKeyTemplate.stringKeyTemplate;
+
 import io.opentelemetry.api.common.AttributeKey;
 import java.util.List;
 
@@ -84,6 +87,28 @@ public final class {{class}} {
     {%- endif %}
   public static final AttributeKey<{{upFirst(to_java_return_type(attribute.attr_type | string))}}> {{attribute.fqn | to_const_name}} = {{to_java_key_type(attribute.attr_type | string)}}("{{attribute.fqn}}");
   {%- endfor %}
+  {%- for attribute_template in attribute_templates if attribute_template.is_local and not attribute_template.ref %}
+
+  /**
+  * {{attribute_template.brief | render_markdown(code="{{@code {0}}}", paragraph="{0}")}}
+    {%- if attribute_template.note %}
+  *
+  * <p>Notes:
+        {# NOTE: replace("> ", "") removes the following problematic characters which produce mangled javadoc:  #}
+        {# https://github.com/open-telemetry/semantic-conventions/blob/c83a10a9c33c18a769835e959200d0e24dc708fe/model/resource/k8s.yaml#L34-L38  #}
+        <ul> {{attribute_template.note | replace("> ", "") | render_markdown(code="{{@code {0}}}", paragraph="<li>{0}</li>", list="{0}")}} </ul>
+
+    {%- endif %}
+    {%- if (attribute_template.stability | string())  == "StabilityLevel.DEPRECATED" %}
+  *
+  * @deprecated {{attribute_template.brief | to_doc_brief}}.
+    {%- endif %}
+  */
+    {%- if (attribute_template.stability | string()) == "StabilityLevel.DEPRECATED"  %}
+  @Deprecated
+    {%- endif %}
+  public static final AttributeKeyTemplate<{{upFirst(to_java_return_type(attribute_template.instantiated_type | string))}}> {{attribute_template.fqn | to_const_name}} = {{to_java_key_type(attribute_template.instantiated_type | string)}}Template("{{attribute_template.fqn}}");
+  {%- endfor %}
 
   // Enum definitions
   {%- for attribute in attributes if attribute.is_local and not attribute.ref %}

src/main/java/io/opentelemetry/semconv/AttributeKeyTemplate.java

@@ -0,0 +1,61 @@
+package io.opentelemetry.semconv;
+
+import io.opentelemetry.api.common.AttributeKey;
+import java.util.List;
+import java.util.Locale;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.function.Function;
+
+public final class AttributeKeyTemplate<T> {
+
+  private final ConcurrentMap<String, AttributeKey<T>> keysCache = new ConcurrentHashMap<>();
+  private final String prefix;
+  private final Function<String, AttributeKey<T>> keyBuilder;
+
+  AttributeKeyTemplate(String prefix, Function<String, AttributeKey<T>> keyBuilder) {
+    this.prefix = prefix;
+    this.keyBuilder = keyBuilder;
+  }
+
+  static AttributeKeyTemplate<String> stringKeyTemplate(String prefix) {
+    return new AttributeKeyTemplate<String>(prefix, AttributeKey::stringKey);
+  }
+
+  static AttributeKeyTemplate<List<String>> stringArrayKeyTemplate(String prefix) {
+    return new AttributeKeyTemplate<List<String>>(prefix, AttributeKey::stringArrayKey);
+  }
+
+  static AttributeKeyTemplate<Boolean> booleanKeyTemplate(String prefix) {
+    return new AttributeKeyTemplate<Boolean>(prefix, AttributeKey::booleanKey);
+  }
+
+  static AttributeKeyTemplate<List<Boolean>> booleanArrayKeyTemplate(String prefix) {
+    return new AttributeKeyTemplate<List<Boolean>>(prefix, AttributeKey::booleanArrayKey);
+  }
+
+  static AttributeKeyTemplate<Long> longKeyTemplate(String prefix) {
+    return new AttributeKeyTemplate<Long>(prefix, AttributeKey::longKey);
+  }
+
+  static AttributeKeyTemplate<List<Long>> longArrayKeyTemplate(String prefix) {
+    return new AttributeKeyTemplate<List<Long>>(prefix, AttributeKey::longArrayKey);
+  }
+
+  static AttributeKeyTemplate<Double> doubleKeyTemplate(String prefix) {
+    return new AttributeKeyTemplate<Double>(prefix, AttributeKey::doubleKey);
+  }
+
+  static AttributeKeyTemplate<List<Double>> doubleArrayKeyTemplate(String prefix) {
+    return new AttributeKeyTemplate<List<Double>>(prefix, AttributeKey::doubleArrayKey);
+  }
+
+  private AttributeKey<T> createAttributeKey(String keyName) {
+    String key = prefix + "." + keyName.toLowerCase(Locale.ROOT).replace('-', '_');
+    return keyBuilder.apply(key);
+  }
+
+  public AttributeKey<T> getAttributeKey(String key) {
+    return keysCache.computeIfAbsent(key, this::createAttributeKey);
+  }
+}