Resource.Builder for convenient work with Resource class

exporters/jaeger-thrift/src/test/java/io/opentelemetry/exporter/jaeger/thrift/JaegerThriftIntegrationTest.java

@@ -8,7 +8,6 @@
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import io.opentelemetry.api.OpenTelemetry;
-import io.opentelemetry.api.common.Attributes;
 import io.opentelemetry.api.trace.Span;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import io.opentelemetry.sdk.resources.Resource;
@@ -67,10 +66,9 @@ private static OpenTelemetry initOpenTelemetry() {
             SdkTracerProvider.builder()
                 .addSpanProcessor(SimpleSpanProcessor.create(jaegerExporter))
                 .setResource(
-                    Resource.getDefault()
-                        .merge(
-                            Resource.create(
-                                Attributes.of(ResourceAttributes.SERVICE_NAME, SERVICE_NAME))))
+                    Resource.getDefault().toBuilder()
+                        .put(ResourceAttributes.SERVICE_NAME, SERVICE_NAME)
+                        .build())
                 .build())
         .build();
   }

exporters/jaeger/src/test/java/io/opentelemetry/exporter/jaeger/JaegerIntegrationTest.java

@@ -10,7 +10,6 @@
 import io.grpc.ManagedChannel;
 import io.grpc.ManagedChannelBuilder;
 import io.opentelemetry.api.OpenTelemetry;
-import io.opentelemetry.api.common.Attributes;
 import io.opentelemetry.api.trace.Span;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
 import io.opentelemetry.sdk.resources.Resource;
@@ -71,10 +70,9 @@ private static OpenTelemetry initOpenTelemetry() {
             SdkTracerProvider.builder()
                 .addSpanProcessor(SimpleSpanProcessor.create(jaegerExporter))
                 .setResource(
-                    Resource.getDefault()
-                        .merge(
-                            Resource.create(
-                                Attributes.of(ResourceAttributes.SERVICE_NAME, SERVICE_NAME))))
+                    Resource.getDefault().toBuilder()
+                        .put(ResourceAttributes.SERVICE_NAME, SERVICE_NAME)
+                        .build())
                 .build())
         .build();
   }

integration-tests/src/test/java/io/opentelemetry/JaegerExporterIntegrationTest.java

@@ -10,7 +10,6 @@
 import io.grpc.ManagedChannel;
 import io.grpc.ManagedChannelBuilder;
 import io.opentelemetry.api.OpenTelemetry;
-import io.opentelemetry.api.common.Attributes;
 import io.opentelemetry.api.trace.Span;
 import io.opentelemetry.exporter.jaeger.JaegerGrpcSpanExporter;
 import io.opentelemetry.sdk.OpenTelemetrySdk;
@@ -117,11 +116,9 @@ private static OpenTelemetry initOpenTelemetry(String ip, int port) {
             SdkTracerProvider.builder()
                 .addSpanProcessor(SimpleSpanProcessor.create(jaegerExporter))
                 .setResource(
-                    Resource.getDefault()
-                        .merge(
-                            Resource.create(
-                                Attributes.of(
-                                    ResourceAttributes.SERVICE_NAME, "integration test"))))
+                    Resource.getDefault().toBuilder()
+                        .put(ResourceAttributes.SERVICE_NAME, "integration test")
+                        .build())
                 .build())
         .buildAndRegisterGlobal();
   }

sdk/common/src/main/java/io/opentelemetry/sdk/resources/Resource.java

@@ -168,4 +168,17 @@ private static boolean isValid(String name) {
   private static boolean isValidAndNotEmpty(AttributeKey<?> name) {
     return !name.getKey().isEmpty() && isValid(name.getKey());
   }
+
+  /** Returns a new {@link ResourceBuilder} instance for creating arbitrary {@link Resource}. */
+  public static ResourceBuilder builder() {
+    return new ResourceBuilder();
+  }
+
+  /**
+   * Returns a new {@link ResourceBuilder} instance populated with the data of this {@link
+   * Resource}.
+   */
+  public ResourceBuilder toBuilder() {
+    return builder().putAll(this);
+  }
 }

sdk/common/src/main/java/io/opentelemetry/sdk/resources/ResourceBuilder.java

@@ -0,0 +1,176 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.resources;
+
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.common.AttributesBuilder;
+
+/**
+ * A builder of {@link Resource} that allows to add key-value pairs and copy attributes from other
+ * {@link Attributes} or {@link Resource}.
+ */
+public class ResourceBuilder {
+
+  private final AttributesBuilder attributesBuilder = Attributes.builder();
+
+  /**
+   * Puts a String attribute into this.
+   *
+   * <p>Note: It is strongly recommended to use {@link #put(AttributeKey, Object)}, and pre-allocate
+   * your keys, if possible.
+   *
+   * @return this Builder
+   */
+  public ResourceBuilder put(String key, String value) {
+    if (key != null && value != null) {
+      attributesBuilder.put(key, value);
+    }
+    return this;
+  }
+
+  /**
+   * Puts a long attribute into this.
+   *
+   * <p>Note: It is strongly recommended to use {@link #put(AttributeKey, Object)}, and pre-allocate
+   * your keys, if possible.
+   *
+   * @return this Builder
+   */
+  public ResourceBuilder put(String key, long value) {
+    if (key != null) {
+      attributesBuilder.put(key, value);
+    }
+    return this;
+  }
+
+  /**
+   * Puts a double attribute into this.
+   *
+   * <p>Note: It is strongly recommended to use {@link #put(AttributeKey, Object)}, and pre-allocate
+   * your keys, if possible.
+   *
+   * @return this Builder
+   */
+  public ResourceBuilder put(String key, double value) {
+    if (key != null) {
+      attributesBuilder.put(key, value);
+    }
+    return this;
+  }
+
+  /**
+   * Puts a boolean attribute into this.
+   *
+   * <p>Note: It is strongly recommended to use {@link #put(AttributeKey, Object)}, and pre-allocate
+   * your keys, if possible.
+   *
+   * @return this Builder
+   */
+  public ResourceBuilder put(String key, boolean value) {
+    if (key != null) {
+      attributesBuilder.put(key, value);
+    }
+    return this;
+  }
+
+  /**
+   * Puts a String array attribute into this.
+   *
+   * <p>Note: It is strongly recommended to use {@link #put(AttributeKey, Object)}, and pre-allocate
+   * your keys, if possible.
+   *
+   * @return this Builder
+   */
+  public ResourceBuilder put(String key, String... values) {
+    if (key != null && values != null) {
+      attributesBuilder.put(key, values);
+    }
+    return this;
+  }
+
+  /**
+   * Puts a Long array attribute into this.
+   *
+   * <p>Note: It is strongly recommended to use {@link #put(AttributeKey, Object)}, and pre-allocate
+   * your keys, if possible.
+   *
+   * @return this Builder
+   */
+  public ResourceBuilder put(String key, long... values) {
+    if (key != null && values != null) {
+      attributesBuilder.put(key, values);
+    }
+    return this;
+  }
+
+  /**
+   * Puts a Double array attribute into this.
+   *
+   * <p>Note: It is strongly recommended to use {@link #put(AttributeKey, Object)}, and pre-allocate
+   * your keys, if possible.
+   *
+   * @return this Builder
+   */
+  public ResourceBuilder put(String key, double... values) {
+    if (key != null && values != null) {
+      attributesBuilder.put(key, values);
+    }
+    return this;
+  }
+
+  /**
+   * Puts a Boolean array attribute into this.
+   *
+   * <p>Note: It is strongly recommended to use {@link #put(AttributeKey, Object)}, and pre-allocate
+   * your keys, if possible.
+   *
+   * @return this Builder
+   */
+  public ResourceBuilder put(String key, boolean... values) {
+    if (key != null && values != null) {
+      attributesBuilder.put(key, values);
+    }
+    return this;
+  }
+
+  /** Puts a {@link AttributeKey} with associated value into this. */
+  public <T> ResourceBuilder put(AttributeKey<T> key, T value) {
+    if (key != null && key.getKey() != null && key.getKey().length() > 0 && value != null) {
+      attributesBuilder.put(key, value);
+    }
+    return this;
+  }
+
+  /** Puts a {@link AttributeKey} with associated value into this. */
+  public ResourceBuilder put(AttributeKey<Long> key, int value) {
+    if (key != null && key.getKey() != null) {
+      attributesBuilder.put(key, value);
+    }
+    return this;
+  }
+
+  /** Puts all {@link Attributes} into this. */
+  public ResourceBuilder putAll(Attributes attributes) {
+    if (attributes != null) {
+      attributesBuilder.putAll(attributes);
+    }
+    return this;
+  }
+
+  /** Puts all attributes from {@link Resource} into this. */
+  public ResourceBuilder putAll(Resource resource) {
+    if (resource != null) {
+      attributesBuilder.putAll(resource.getAttributes());
+    }
+    return this;
+  }
+
+  /** Create the {@link Resource} from this. */
+  public Resource build() {
+    return Resource.create(attributesBuilder.build());
+  }
+}

sdk/common/src/test/java/io/opentelemetry/sdk/resources/ResourceTest.java

@@ -193,4 +193,76 @@ void testDefaultResources() {
     assertThat(attributes.get(ResourceAttributes.TELEMETRY_SDK_LANGUAGE)).isEqualTo("java");
     assertThat(attributes.get(ResourceAttributes.TELEMETRY_SDK_VERSION)).isNotNull();
   }
+
+  @Test
+  void shouldBuilderNotFailWithNullResource() {
+    // given
+    ResourceBuilder builder = Resource.getDefault().toBuilder();
+
+    // when
+    builder.putAll((Resource) null);
+
+    // then no exception is thrown
+    // and
+    assertThat(builder.build().getAttributes().get(ResourceAttributes.SERVICE_NAME))
+        .isEqualTo("unknown_service:java");
+  }
+
+  @Test
+  void shouldBuilderCopyResource() {
+    // given
+    ResourceBuilder builder = Resource.getDefault().toBuilder();
+
+    // when
+    builder.put("dog says what?", "woof");
+
+    // then
+    Resource resource = builder.build();
+    assertThat(resource).isNotSameAs(Resource.getDefault());
+    assertThat(resource.getAttributes().get(stringKey("dog says what?"))).isEqualTo("woof");
+  }
+
+  @Test
+  void shouldBuilderHelperMethodsBuildResource() {
+    // given
+    ResourceBuilder builder = Resource.getDefault().toBuilder();
+    Attributes sourceAttributes = Attributes.of(stringKey("hello"), "world");
+    Resource source = Resource.create(sourceAttributes);
+    Attributes sourceAttributes2 = Attributes.of(stringKey("OpenTelemetry"), "Java");
+
+    // when
+    Resource resource =
+        builder
+            .put("long", 42L)
+            .put("double", Math.E)
+            .put("boolean", true)
+            .put("string", "abc")
+            .put("long array", 1L, 2L, 3L)
+            .put("double array", Math.E, Math.PI)
+            .put("boolean array", true, false)
+            .put("string array", "first", "second")
+            .put(longKey("long key"), 4242L)
+            .put(longKey("int in disguise"), 21)
+            .putAll(source)
+            .putAll(sourceAttributes2)
+            .build();
+
+    // then
+    Attributes attributes = resource.getAttributes();
+    assertThat(attributes.get(longKey("long"))).isEqualTo(42L);
+    assertThat(attributes.get(doubleKey("double"))).isEqualTo(Math.E);
+    assertThat(attributes.get(booleanKey("boolean"))).isEqualTo(true);
+    assertThat(attributes.get(stringKey("string"))).isEqualTo("abc");
+    assertThat(attributes.get(longArrayKey("long array"))).isEqualTo(Arrays.asList(1L, 2L, 3L));
+    assertThat(attributes.get(doubleArrayKey("double array")))
+        .isEqualTo(Arrays.asList(Math.E, Math.PI));
+    assertThat(attributes.get(booleanArrayKey("boolean array")))
+        .isEqualTo(Arrays.asList(true, false));
+    assertThat(attributes.get(stringArrayKey("string array")))
+        .isEqualTo(Arrays.asList("first", "second"));
+    assertThat(attributes.get(longKey("long key"))).isEqualTo(4242L);
+    assertThat(attributes.get(longKey("int in disguise"))).isEqualTo(21);
+    assertThat(attributes.get(stringKey("hello"))).isEqualTo("world");
+    assertThat(attributes.get(stringKey("OpenTelemetry"))).isEqualTo("Java");
+  }
 }