From 5539c10c51d5005c81610f7c090d6a09416d2a2d Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Sat, 17 Nov 2018 15:52:43 -0800
Subject: [PATCH 1/6] Add Resource API

---
 .../src/internal/string-utils.ts              |  41 ++++
 .../opencensus-core/src/resource/resource.ts  | 192 ++++++++++++++++++
 .../opencensus-core/test/test-resource.ts     |  93 +++++++++
 .../opencensus-core/test/test-string-utils.ts |  30 +++
 4 files changed, 356 insertions(+)
 create mode 100644 packages/opencensus-core/src/internal/string-utils.ts
 create mode 100644 packages/opencensus-core/src/resource/resource.ts
 create mode 100644 packages/opencensus-core/test/test-resource.ts
 create mode 100644 packages/opencensus-core/test/test-string-utils.ts

diff --git a/packages/opencensus-core/src/internal/string-utils.ts b/packages/opencensus-core/src/internal/string-utils.ts
new file mode 100644
index 000000000..54d18898e
--- /dev/null
+++ b/packages/opencensus-core/src/internal/string-utils.ts
@@ -0,0 +1,41 @@
+/**
+ * Copyright 2018 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/**
+ * Internal utility methods for working with tag keys, tag values, and metric
+ * names.
+ */
+export class StringUtils {
+  /**
+   * Determines whether the String contains only printable characters.
+   *
+   * @param {string} str the String to be validated.
+   * @return whether the String contains only printable characters.
+   */
+  static isPrintableString(str: string): boolean {
+    for (let i = 0; i < str.length; i++) {
+      const ch: string = str.charAt(i);
+      if (!StringUtils.isPrintableChar(ch)) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  static isPrintableChar(ch: string): boolean {
+    return ch >= ' ' && ch <= '~';
+  }
+}
diff --git a/packages/opencensus-core/src/resource/resource.ts b/packages/opencensus-core/src/resource/resource.ts
new file mode 100644
index 000000000..c2d27489c
--- /dev/null
+++ b/packages/opencensus-core/src/resource/resource.ts
@@ -0,0 +1,192 @@
+/**
+ * Copyright 2018, OpenCensus Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import {StringUtils} from '../internal/string-utils';
+
+/**
+ * Resource represents a resource, which capture identifying information about
+ * the entities for which signals (stats or traces) are reported. It further
+ * provides a framework for detection of resource information from the
+ * environment and progressive population as signals propagate from the core
+ * instrumentation library to a backend's exporter.
+ */
+export class Resource {
+  /**
+   * The type identifier for the resource.
+   */
+  private readonly type: string|null;
+  /**
+   * A map of labels that describe the resource.
+   */
+  private readonly labels: StringMap;
+
+  private static readonly MAX_LENGTH = 255;
+  private static readonly LABEL_LIST_SPLITTER = ',';
+  private static readonly LABEL_KEY_VALUE_SPLITTER = '=';
+  private static readonly ENV_TYPE =
+      Resource.parseResourceType(process.env.OC_RESOURCE_TYPE);
+  private static readonly ENV_LABEL_MAP =
+      Resource.parseResourceLabels(process.env.OC_RESOURCE_LABELS);
+  private static readonly ERROR_MESSAGE_INVALID_CHARS =
+      'should be a ASCII string with a length greater than 0 and not exceed ' +
+      Resource.MAX_LENGTH + ' characters.';
+  private static readonly ERROR_MESSAGE_INVALID_VALUE =
+      'should be a ASCII string with a length not exceed ' +
+      Resource.MAX_LENGTH + ' characters.';
+
+  constructor(type: string, labels: StringMap) {
+    this.type = type;
+    this.labels = labels;
+  }
+
+  /**
+   * Returns a Resource. This resource information is loaded from the
+   * OC_RESOURCE_TYPE and OC_RESOURCE_LABELS environment variables.
+   *
+   * @returns {Resource}
+   */
+  static createFromEnvironmentVariables(): Resource {
+    return new Resource(Resource.ENV_TYPE, Resource.ENV_LABEL_MAP);
+  }
+
+  /**
+   * Returns a Resource that runs all input resources sequentially and merges
+   * their results. In case a type of label key is already set, the first set
+   * value takes precedence.
+   *
+   * @param  {Resource[]} resources the list of the resources.
+   * @returns {Resource}
+   */
+  static mergeResources(resources: Resource[]): Resource {
+    let currentResource: Resource = null;
+    for (const resource of resources) {
+      currentResource = this.merge(currentResource, resource);
+    }
+    return currentResource;
+  }
+
+  /**
+   * Returns the type identifier for the resource.
+   *
+   * @returns {string}
+   */
+  getType(): string {
+    return this.type;
+  }
+
+  /**
+   * Returns a map of labels that describe the resource.
+   *
+   * @returns {StringMap}
+   */
+  getLabels(): StringMap {
+    return this.labels;
+  }
+
+  /**
+   * Creates a resource type from the OC_RESOURCE_TYPE environment variable.
+   *
+   * <p>OC_RESOURCE_TYPE: A string that describes the type of the resource
+   * prefixed by a domain namespace, e.g. “kubernetes.io/container”.
+   */
+  private static parseResourceType(rawEnvType: string): string {
+    if (rawEnvType && rawEnvType != null) {
+      if (!Resource.isValidAndNotEmpty(rawEnvType)) {
+        throw new Error(`Type ${Resource.ERROR_MESSAGE_INVALID_CHARS}`);
+      }
+      return rawEnvType.trim();
+    }
+    return null;
+  }
+
+  /**
+   * Creates a label map from the OC_RESOURCE_LABELS environment variable.
+   *
+   * <p>OC_RESOURCE_LABELS: A comma-separated list of labels describing the
+   * source in more detail, e.g. “key1=val1,key2=val2”. Domain names and paths
+   * are accepted as label keys. Values may be quoted or unquoted in general. If
+   * a value contains whitespaces, =, or " characters, it must always be quoted.
+   */
+  private static parseResourceLabels(rawEnvLabels: string): StringMap {
+    const labels: StringMap = {};
+    if (rawEnvLabels && rawEnvLabels != null) {
+      const rawLabels: string[] =
+          rawEnvLabels.split(this.LABEL_LIST_SPLITTER, -1);
+      for (const rawLabel of rawLabels) {
+        const keyValuePair: string[] =
+            rawLabel.split(this.LABEL_KEY_VALUE_SPLITTER, -1);
+        if (keyValuePair.length !== 2) {
+          continue;
+        }
+        const key: string = keyValuePair[0].trim();
+        const value: string = keyValuePair[1].trim().replace('^"|"$', '');
+        if (!Resource.isValidAndNotEmpty(key)) {
+          throw new Error(`Label key ${Resource.ERROR_MESSAGE_INVALID_CHARS}`);
+        }
+        if (!Resource.isValid(value)) {
+          throw new Error(
+              `Label value ${Resource.ERROR_MESSAGE_INVALID_VALUE}`);
+        }
+        labels[key] = value;
+      }
+    }
+    return labels;
+  }
+
+  /**
+   * Returns a new, merged Resource by merging two resources. In case of
+   * a collision, first resource takes precedence.
+   */
+  private static merge(resource: Resource, otherResource: Resource): Resource {
+    if (resource == null) {
+      return otherResource;
+    }
+    if (otherResource == null) {
+      return resource;
+    }
+    const mergedType: string = resource.getType() != null ?
+        resource.getType() :
+        otherResource.getType();
+    const mergedLabelMap: StringMap = otherResource.getLabels();
+
+    const resourceLabels = resource.getLabels();
+    for (const key of Object.keys(resourceLabels)) {
+      const value = resourceLabels[key];
+      mergedLabelMap[key] = value;
+    }
+    return new Resource(mergedType, mergedLabelMap);
+  }
+
+
+  /**
+   * Determines whether the given String is a valid printable ASCII string with
+   * a length not exceed MAX_LENGTH characters.
+   */
+  private static isValid(name: string): boolean {
+    return name.length <= Resource.MAX_LENGTH &&
+        StringUtils.isPrintableString(name);
+  }
+
+  /**
+   * Determines whether the given String is a valid printable ASCII string with
+   * a length greater than 0 and not exceed MAX_LENGTH characters.
+   */
+  private static isValidAndNotEmpty(name: string): boolean {
+    return name && name.length > 0 && Resource.isValid(name);
+  }
+}
+
+export interface StringMap { [key: string]: string; }
diff --git a/packages/opencensus-core/test/test-resource.ts b/packages/opencensus-core/test/test-resource.ts
new file mode 100644
index 000000000..2ec98c8c3
--- /dev/null
+++ b/packages/opencensus-core/test/test-resource.ts
@@ -0,0 +1,93 @@
+/**
+ * Copyright 2018, OpenCensus Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as assert from 'assert';
+
+process.env.OC_RESOURCE_TYPE = 'k8s.io/container';
+process.env.OC_RESOURCE_LABELS =
+    'k8s.io/pod/name="pod-xyz-123",k8s.io/container/name="c1",k8s.io/namespace/name="default"';
+
+import {Resource} from '../src/resource/resource';
+
+const DEFAULT_RESOURCE = new Resource(null, {});
+const DEFAULT_RESOURCE_1 = new Resource('default', {'a': '100'});
+const RESOURCE_1 = new Resource('t1', {'a': '1', 'b': '2'});
+const RESOURCE_2 = new Resource('t2', {'a': '1', 'b': '3', 'c': '4'});
+
+describe('Resource()', () => {
+  afterEach(() => {
+    delete process.env.OC_RESOURCE_TYPE;
+    delete process.env.OC_RESOURCE_LABELS;
+  });
+
+  it('should return resource information from environment variables', () => {
+    const resource = Resource.createFromEnvironmentVariables();
+    const actualLabels = resource.getLabels();
+    const expectedLabels: {[key: string]: string} = {
+      'k8s.io/container/name': '"c1"',
+      'k8s.io/namespace/name': '"default"',
+      'k8s.io/pod/name': '"pod-xyz-123"'
+    };
+
+    assert.strictEqual(resource.getType(), 'k8s.io/container');
+    assert.equal(Object.keys(actualLabels).length, 3);
+    assert.deepEqual(actualLabels, expectedLabels);
+  });
+});
+
+describe('mergeResources()', () => {
+  it('merge resources with default, resource1', () => {
+    const resources: Resource[] = [DEFAULT_RESOURCE, RESOURCE_1];
+    const resource = Resource.mergeResources(resources);
+    const expectedLabels: {[key: string]: string} = {'a': '1', 'b': '2'};
+
+    assert.equal(resource.getType(), 't1');
+    assert.equal(Object.keys(resource.getLabels()).length, 2);
+    assert.deepEqual(resource.getLabels(), expectedLabels);
+  });
+
+  it('merge resources with default, resource1, resource2 = null', () => {
+    const resources: Resource[] = [DEFAULT_RESOURCE, RESOURCE_1, null];
+    const resource = Resource.mergeResources(resources);
+    const expectedLabels: {[key: string]: string} = {'a': '1', 'b': '2'};
+
+    assert.equal(resource.getType(), 't1');
+    assert.equal(Object.keys(resource.getLabels()).length, 2);
+    assert.deepEqual(resource.getLabels(), expectedLabels);
+  });
+
+  it('merge resources with default, resource1 = null, resource2', () => {
+    const resources: Resource[] = [DEFAULT_RESOURCE, null, RESOURCE_2];
+    const resource = Resource.mergeResources(resources);
+    const expectedLabels:
+        {[key: string]: string} = {'a': '1', 'b': '3', 'c': '4'};
+
+    assert.equal(resource.getType(), 't2');
+    assert.equal(Object.keys(resource.getLabels()).length, 3);
+    assert.deepEqual(resource.getLabels(), expectedLabels);
+  });
+
+  it('merge resources with default1, resource1, resource2', () => {
+    const resources: Resource[] = [DEFAULT_RESOURCE_1, RESOURCE_1, RESOURCE_2];
+    const resource = Resource.mergeResources(resources);
+    const expectedLabels:
+        {[key: string]: string} = {'a': '100', 'b': '2', 'c': '4'};
+
+    assert.equal(resource.getType(), 'default');
+    assert.equal(Object.keys(resource.getLabels()).length, 3);
+    assert.deepEqual(resource.getLabels(), expectedLabels);
+  });
+});
diff --git a/packages/opencensus-core/test/test-string-utils.ts b/packages/opencensus-core/test/test-string-utils.ts
new file mode 100644
index 000000000..fed4ff924
--- /dev/null
+++ b/packages/opencensus-core/test/test-string-utils.ts
@@ -0,0 +1,30 @@
+/**
+ * Copyright 2018, OpenCensus Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import * as assert from 'assert';
+import {StringUtils} from '../src/internal/string-utils';
+
+describe('StringUtils', () => {
+  it('should return true when string is printable', () => {
+    const isValid = StringUtils.isPrintableString('abcd');
+    assert.deepStrictEqual(isValid, true);
+  });
+
+  it('should return false when string is not printable', () => {
+    const isValid = StringUtils.isPrintableString('\x00-\xFF');
+    assert.deepStrictEqual(isValid, false);
+  });
+});

From 017ebbe7677d57f8ec8211db0dd5ec7f46ccac73 Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Mon, 19 Nov 2018 17:17:06 -0800
Subject: [PATCH 2/6] Fix reviews

---
 packages/opencensus-core/src/internal/string-utils.ts | 10 ++++++++--
 packages/opencensus-core/src/resource/resource.ts     |  8 ++++----
 packages/opencensus-core/test/test-resource.ts        | 11 +++++++++++
 3 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/packages/opencensus-core/src/internal/string-utils.ts b/packages/opencensus-core/src/internal/string-utils.ts
index 54d18898e..be51d3bbf 100644
--- a/packages/opencensus-core/src/internal/string-utils.ts
+++ b/packages/opencensus-core/src/internal/string-utils.ts
@@ -22,8 +22,8 @@ export class StringUtils {
   /**
    * Determines whether the String contains only printable characters.
    *
-   * @param {string} str the String to be validated.
-   * @return whether the String contains only printable characters.
+   * @param {string} str The String to be validated.
+   * @return {boolean} Whether the String contains only printable characters.
    */
   static isPrintableString(str: string): boolean {
     for (let i = 0; i < str.length; i++) {
@@ -35,6 +35,12 @@ export class StringUtils {
     return true;
   }
 
+  /**
+   * Determines whether the Character is printable.
+   *
+   * @param {string} str The Character to be validated.
+   * @return {boolean} Whether the Character is printable.
+   */
   static isPrintableChar(ch: string): boolean {
     return ch >= ' ' && ch <= '~';
   }
diff --git a/packages/opencensus-core/src/resource/resource.ts b/packages/opencensus-core/src/resource/resource.ts
index c2d27489c..02d48d163 100644
--- a/packages/opencensus-core/src/resource/resource.ts
+++ b/packages/opencensus-core/src/resource/resource.ts
@@ -103,7 +103,7 @@ export class Resource {
    * prefixed by a domain namespace, e.g. “kubernetes.io/container”.
    */
   private static parseResourceType(rawEnvType: string): string {
-    if (rawEnvType && rawEnvType != null) {
+    if (rawEnvType) {
       if (!Resource.isValidAndNotEmpty(rawEnvType)) {
         throw new Error(`Type ${Resource.ERROR_MESSAGE_INVALID_CHARS}`);
       }
@@ -122,7 +122,7 @@ export class Resource {
    */
   private static parseResourceLabels(rawEnvLabels: string): StringMap {
     const labels: StringMap = {};
-    if (rawEnvLabels && rawEnvLabels != null) {
+    if (rawEnvLabels) {
       const rawLabels: string[] =
           rawEnvLabels.split(this.LABEL_LIST_SPLITTER, -1);
       for (const rawLabel of rawLabels) {
@@ -151,10 +151,10 @@ export class Resource {
    * a collision, first resource takes precedence.
    */
   private static merge(resource: Resource, otherResource: Resource): Resource {
-    if (resource == null) {
+    if (!resource) {
       return otherResource;
     }
-    if (otherResource == null) {
+    if (!otherResource) {
       return resource;
     }
     const mergedType: string = resource.getType() != null ?
diff --git a/packages/opencensus-core/test/test-resource.ts b/packages/opencensus-core/test/test-resource.ts
index 2ec98c8c3..42f2b7901 100644
--- a/packages/opencensus-core/test/test-resource.ts
+++ b/packages/opencensus-core/test/test-resource.ts
@@ -90,4 +90,15 @@ describe('mergeResources()', () => {
     assert.equal(Object.keys(resource.getLabels()).length, 3);
     assert.deepEqual(resource.getLabels(), expectedLabels);
   });
+
+  it('merge resources with default, resource1 = undefined, resource2 = undefined',
+     () => {
+       const resources: Resource[] = [DEFAULT_RESOURCE_1, undefined, undefined];
+       const resource = Resource.mergeResources(resources);
+       const expectedLabels: {[key: string]: string} = {'a': '100'};
+
+       assert.equal(resource.getType(), 'default');
+       assert.equal(Object.keys(resource.getLabels()).length, 1);
+       assert.deepEqual(resource.getLabels(), expectedLabels);
+     });
 });

From cdbc33fdbd9ffff355eef263a82250adefbe6e9e Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Sun, 25 Nov 2018 16:32:55 -0800
Subject: [PATCH 3/6] Add interface: Resource

---
 .../src/internal/string-utils.ts              |   4 +-
 .../opencensus-core/src/resource/resource.ts  | 122 ++++++++----------
 .../opencensus-core/src/resource/types.ts     |  29 +++++
 .../opencensus-core/test/test-resource.ts     |  71 +++++-----
 4 files changed, 125 insertions(+), 101 deletions(-)
 create mode 100644 packages/opencensus-core/src/resource/types.ts

diff --git a/packages/opencensus-core/src/internal/string-utils.ts b/packages/opencensus-core/src/internal/string-utils.ts
index be51d3bbf..966a8e66a 100644
--- a/packages/opencensus-core/src/internal/string-utils.ts
+++ b/packages/opencensus-core/src/internal/string-utils.ts
@@ -23,7 +23,7 @@ export class StringUtils {
    * Determines whether the String contains only printable characters.
    *
    * @param {string} str The String to be validated.
-   * @return {boolean} Whether the String contains only printable characters.
+   * @returns {boolean} Whether the String contains only printable characters.
    */
   static isPrintableString(str: string): boolean {
     for (let i = 0; i < str.length; i++) {
@@ -39,7 +39,7 @@ export class StringUtils {
    * Determines whether the Character is printable.
    *
    * @param {string} str The Character to be validated.
-   * @return {boolean} Whether the Character is printable.
+   * @returns {boolean} Whether the Character is printable.
    */
   static isPrintableChar(ch: string): boolean {
     return ch >= ' ' && ch <= '~';
diff --git a/packages/opencensus-core/src/resource/resource.ts b/packages/opencensus-core/src/resource/resource.ts
index 02d48d163..600e7c766 100644
--- a/packages/opencensus-core/src/resource/resource.ts
+++ b/packages/opencensus-core/src/resource/resource.ts
@@ -15,6 +15,7 @@
  */
 
 import {StringUtils} from '../internal/string-utils';
+import {Resource} from './types';
 
 /**
  * Resource represents a resource, which capture identifying information about
@@ -23,43 +24,30 @@ import {StringUtils} from '../internal/string-utils';
  * environment and progressive population as signals propagate from the core
  * instrumentation library to a backend's exporter.
  */
-export class Resource {
-  /**
-   * The type identifier for the resource.
-   */
-  private readonly type: string|null;
-  /**
-   * A map of labels that describe the resource.
-   */
-  private readonly labels: StringMap;
-
+export class CoreResource {
+  // Type, label keys, and label values should not exceed 256 characters.
   private static readonly MAX_LENGTH = 255;
-  private static readonly LABEL_LIST_SPLITTER = ',';
+  private static readonly COMMA_SEPARATOR = ',';
   private static readonly LABEL_KEY_VALUE_SPLITTER = '=';
   private static readonly ENV_TYPE =
-      Resource.parseResourceType(process.env.OC_RESOURCE_TYPE);
+      CoreResource.parseResourceType(process.env.OC_RESOURCE_TYPE);
   private static readonly ENV_LABEL_MAP =
-      Resource.parseResourceLabels(process.env.OC_RESOURCE_LABELS);
+      CoreResource.parseResourceLabels(process.env.OC_RESOURCE_LABELS);
   private static readonly ERROR_MESSAGE_INVALID_CHARS =
       'should be a ASCII string with a length greater than 0 and not exceed ' +
-      Resource.MAX_LENGTH + ' characters.';
+      CoreResource.MAX_LENGTH + ' characters.';
   private static readonly ERROR_MESSAGE_INVALID_VALUE =
       'should be a ASCII string with a length not exceed ' +
-      Resource.MAX_LENGTH + ' characters.';
-
-  constructor(type: string, labels: StringMap) {
-    this.type = type;
-    this.labels = labels;
-  }
+      CoreResource.MAX_LENGTH + ' characters.';
 
   /**
    * Returns a Resource. This resource information is loaded from the
    * OC_RESOURCE_TYPE and OC_RESOURCE_LABELS environment variables.
    *
-   * @returns {Resource}
+   * @returns {Resource} The resource.
    */
   static createFromEnvironmentVariables(): Resource {
-    return new Resource(Resource.ENV_TYPE, Resource.ENV_LABEL_MAP);
+    return {type: CoreResource.ENV_TYPE, labels: CoreResource.ENV_LABEL_MAP};
   }
 
   /**
@@ -67,45 +55,30 @@ export class Resource {
    * their results. In case a type of label key is already set, the first set
    * value takes precedence.
    *
-   * @param  {Resource[]} resources the list of the resources.
-   * @returns {Resource}
+   * @param  {Resource[]} resources The list of the resources.
+   * @returns {Resource} The resource.
    */
   static mergeResources(resources: Resource[]): Resource {
-    let currentResource: Resource = null;
+    let currentResource: Resource;
     for (const resource of resources) {
       currentResource = this.merge(currentResource, resource);
     }
     return currentResource;
   }
 
-  /**
-   * Returns the type identifier for the resource.
-   *
-   * @returns {string}
-   */
-  getType(): string {
-    return this.type;
-  }
-
-  /**
-   * Returns a map of labels that describe the resource.
-   *
-   * @returns {StringMap}
-   */
-  getLabels(): StringMap {
-    return this.labels;
-  }
-
   /**
    * Creates a resource type from the OC_RESOURCE_TYPE environment variable.
    *
    * <p>OC_RESOURCE_TYPE: A string that describes the type of the resource
    * prefixed by a domain namespace, e.g. “kubernetes.io/container”.
+   *
+   * @param  {string} rawEnvType The resource type.
+   * @returns {string} The sanitized resource type.
    */
   private static parseResourceType(rawEnvType: string): string {
     if (rawEnvType) {
-      if (!Resource.isValidAndNotEmpty(rawEnvType)) {
-        throw new Error(`Type ${Resource.ERROR_MESSAGE_INVALID_CHARS}`);
+      if (!CoreResource.isValidAndNotEmpty(rawEnvType)) {
+        throw new Error(`Type ${CoreResource.ERROR_MESSAGE_INVALID_CHARS}`);
       }
       return rawEnvType.trim();
     }
@@ -119,26 +92,34 @@ export class Resource {
    * source in more detail, e.g. “key1=val1,key2=val2”. Domain names and paths
    * are accepted as label keys. Values may be quoted or unquoted in general. If
    * a value contains whitespaces, =, or " characters, it must always be quoted.
+   *
+   * @param {string} rawEnvLabels The resource labels as a comma-seperated list
+   * of key/value pairs.
+   * @returns {[key: string]: string} The sanitized resource labels.
    */
-  private static parseResourceLabels(rawEnvLabels: string): StringMap {
-    const labels: StringMap = {};
+  private static parseResourceLabels(rawEnvLabels: string):
+      {[key: string]: string;} {
+    const labels: {[key: string]: string;} = {};
     if (rawEnvLabels) {
-      const rawLabels: string[] =
-          rawEnvLabels.split(this.LABEL_LIST_SPLITTER, -1);
+      const rawLabels: string[] = rawEnvLabels.split(this.COMMA_SEPARATOR, -1);
+      let key, value;
       for (const rawLabel of rawLabels) {
         const keyValuePair: string[] =
             rawLabel.split(this.LABEL_KEY_VALUE_SPLITTER, -1);
         if (keyValuePair.length !== 2) {
           continue;
         }
-        const key: string = keyValuePair[0].trim();
-        const value: string = keyValuePair[1].trim().replace('^"|"$', '');
-        if (!Resource.isValidAndNotEmpty(key)) {
-          throw new Error(`Label key ${Resource.ERROR_MESSAGE_INVALID_CHARS}`);
+        [key, value] = keyValuePair;
+        // Leading and trailing whitespaces are trimmed.
+        key = key.trim();
+        value = value.trim().split('^"|"$').join('');
+        if (!CoreResource.isValidAndNotEmpty(key)) {
+          throw new Error(
+              `Label key ${CoreResource.ERROR_MESSAGE_INVALID_CHARS}`);
         }
-        if (!Resource.isValid(value)) {
+        if (!CoreResource.isValid(value)) {
           throw new Error(
-              `Label value ${Resource.ERROR_MESSAGE_INVALID_VALUE}`);
+              `Label value ${CoreResource.ERROR_MESSAGE_INVALID_VALUE}`);
         }
         labels[key] = value;
       }
@@ -149,6 +130,10 @@ export class Resource {
   /**
    * Returns a new, merged Resource by merging two resources. In case of
    * a collision, first resource takes precedence.
+   *
+   * @param {Resource} resource The resource object.
+   * @param {Resource} otherResource The resource object.
+   * @returns {Resource} A new, merged Resource.
    */
   private static merge(resource: Resource, otherResource: Resource): Resource {
     if (!resource) {
@@ -157,36 +142,33 @@ export class Resource {
     if (!otherResource) {
       return resource;
     }
-    const mergedType: string = resource.getType() != null ?
-        resource.getType() :
-        otherResource.getType();
-    const mergedLabelMap: StringMap = otherResource.getLabels();
-
-    const resourceLabels = resource.getLabels();
-    for (const key of Object.keys(resourceLabels)) {
-      const value = resourceLabels[key];
-      mergedLabelMap[key] = value;
-    }
-    return new Resource(mergedType, mergedLabelMap);
+    return {
+      type: resource.type || otherResource.type,
+      labels: Object.assign(otherResource.labels, resource.labels)
+    };
   }
 
 
   /**
    * Determines whether the given String is a valid printable ASCII string with
    * a length not exceed MAX_LENGTH characters.
+   *
+   * @param {string} str The String to be validated.
+   * @returns {boolean} Whether the String is valid.
    */
   private static isValid(name: string): boolean {
-    return name.length <= Resource.MAX_LENGTH &&
+    return name.length <= CoreResource.MAX_LENGTH &&
         StringUtils.isPrintableString(name);
   }
 
   /**
    * Determines whether the given String is a valid printable ASCII string with
    * a length greater than 0 and not exceed MAX_LENGTH characters.
+   *
+   * @param {string} str The String to be validated.
+   * @returns {boolean} Whether the String is valid and not empty.
    */
   private static isValidAndNotEmpty(name: string): boolean {
-    return name && name.length > 0 && Resource.isValid(name);
+    return name && name.length > 0 && CoreResource.isValid(name);
   }
 }
-
-export interface StringMap { [key: string]: string; }
diff --git a/packages/opencensus-core/src/resource/types.ts b/packages/opencensus-core/src/resource/types.ts
new file mode 100644
index 000000000..8a39994e2
--- /dev/null
+++ b/packages/opencensus-core/src/resource/types.ts
@@ -0,0 +1,29 @@
+/**
+ * Copyright 2018, OpenCensus Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/** A Resource describes the entity for which a signal was collected. */
+export interface Resource {
+  /**
+   * An optional string which describes a well-known type of resource.
+   */
+  readonly type: string|null;
+
+  /**
+   * A dictionary of labels with string keys and values that provide information
+   * about the entity.
+   */
+  readonly labels: {[key: string]: string;};
+}
diff --git a/packages/opencensus-core/test/test-resource.ts b/packages/opencensus-core/test/test-resource.ts
index 42f2b7901..0d79bceea 100644
--- a/packages/opencensus-core/test/test-resource.ts
+++ b/packages/opencensus-core/test/test-resource.ts
@@ -20,12 +20,25 @@ process.env.OC_RESOURCE_TYPE = 'k8s.io/container';
 process.env.OC_RESOURCE_LABELS =
     'k8s.io/pod/name="pod-xyz-123",k8s.io/container/name="c1",k8s.io/namespace/name="default"';
 
-import {Resource} from '../src/resource/resource';
-
-const DEFAULT_RESOURCE = new Resource(null, {});
-const DEFAULT_RESOURCE_1 = new Resource('default', {'a': '100'});
-const RESOURCE_1 = new Resource('t1', {'a': '1', 'b': '2'});
-const RESOURCE_2 = new Resource('t2', {'a': '1', 'b': '3', 'c': '4'});
+import {CoreResource} from '../src/resource/resource';
+import {Resource} from '../src/resource/types';
+
+const DEFAULT_RESOURCE: Resource = {
+  type: null,
+  labels: {}
+};
+const DEFAULT_RESOURCE_1: Resource = {
+  type: 'default',
+  labels: {'a': '100'}
+};
+const RESOURCE_1: Resource = {
+  type: 't1',
+  labels: {'a': '1', 'b': '2'}
+};
+const RESOURCE_2: Resource = {
+  type: 't2',
+  labels: {'a': '1', 'b': '3', 'c': '4'}
+};
 
 describe('Resource()', () => {
   afterEach(() => {
@@ -34,15 +47,15 @@ describe('Resource()', () => {
   });
 
   it('should return resource information from environment variables', () => {
-    const resource = Resource.createFromEnvironmentVariables();
-    const actualLabels = resource.getLabels();
+    const resource = CoreResource.createFromEnvironmentVariables();
+    const actualLabels = resource.labels;
     const expectedLabels: {[key: string]: string} = {
       'k8s.io/container/name': '"c1"',
       'k8s.io/namespace/name': '"default"',
       'k8s.io/pod/name': '"pod-xyz-123"'
     };
 
-    assert.strictEqual(resource.getType(), 'k8s.io/container');
+    assert.strictEqual(resource.type, 'k8s.io/container');
     assert.equal(Object.keys(actualLabels).length, 3);
     assert.deepEqual(actualLabels, expectedLabels);
   });
@@ -51,54 +64,54 @@ describe('Resource()', () => {
 describe('mergeResources()', () => {
   it('merge resources with default, resource1', () => {
     const resources: Resource[] = [DEFAULT_RESOURCE, RESOURCE_1];
-    const resource = Resource.mergeResources(resources);
+    const resource = CoreResource.mergeResources(resources);
     const expectedLabels: {[key: string]: string} = {'a': '1', 'b': '2'};
 
-    assert.equal(resource.getType(), 't1');
-    assert.equal(Object.keys(resource.getLabels()).length, 2);
-    assert.deepEqual(resource.getLabels(), expectedLabels);
+    assert.equal(resource.type, 't1');
+    assert.equal(Object.keys(resource.labels).length, 2);
+    assert.deepEqual(resource.labels, expectedLabels);
   });
 
   it('merge resources with default, resource1, resource2 = null', () => {
     const resources: Resource[] = [DEFAULT_RESOURCE, RESOURCE_1, null];
-    const resource = Resource.mergeResources(resources);
+    const resource = CoreResource.mergeResources(resources);
     const expectedLabels: {[key: string]: string} = {'a': '1', 'b': '2'};
 
-    assert.equal(resource.getType(), 't1');
-    assert.equal(Object.keys(resource.getLabels()).length, 2);
-    assert.deepEqual(resource.getLabels(), expectedLabels);
+    assert.equal(resource.type, 't1');
+    assert.equal(Object.keys(resource.labels).length, 2);
+    assert.deepEqual(resource.labels, expectedLabels);
   });
 
   it('merge resources with default, resource1 = null, resource2', () => {
     const resources: Resource[] = [DEFAULT_RESOURCE, null, RESOURCE_2];
-    const resource = Resource.mergeResources(resources);
+    const resource = CoreResource.mergeResources(resources);
     const expectedLabels:
         {[key: string]: string} = {'a': '1', 'b': '3', 'c': '4'};
 
-    assert.equal(resource.getType(), 't2');
-    assert.equal(Object.keys(resource.getLabels()).length, 3);
-    assert.deepEqual(resource.getLabels(), expectedLabels);
+    assert.equal(resource.type, 't2');
+    assert.equal(Object.keys(resource.labels).length, 3);
+    assert.deepEqual(resource.labels, expectedLabels);
   });
 
   it('merge resources with default1, resource1, resource2', () => {
     const resources: Resource[] = [DEFAULT_RESOURCE_1, RESOURCE_1, RESOURCE_2];
-    const resource = Resource.mergeResources(resources);
+    const resource = CoreResource.mergeResources(resources);
     const expectedLabels:
         {[key: string]: string} = {'a': '100', 'b': '2', 'c': '4'};
 
-    assert.equal(resource.getType(), 'default');
-    assert.equal(Object.keys(resource.getLabels()).length, 3);
-    assert.deepEqual(resource.getLabels(), expectedLabels);
+    assert.equal(resource.type, 'default');
+    assert.equal(Object.keys(resource.labels).length, 3);
+    assert.deepEqual(resource.labels, expectedLabels);
   });
 
   it('merge resources with default, resource1 = undefined, resource2 = undefined',
      () => {
        const resources: Resource[] = [DEFAULT_RESOURCE_1, undefined, undefined];
-       const resource = Resource.mergeResources(resources);
+       const resource = CoreResource.mergeResources(resources);
        const expectedLabels: {[key: string]: string} = {'a': '100'};
 
-       assert.equal(resource.getType(), 'default');
-       assert.equal(Object.keys(resource.getLabels()).length, 1);
-       assert.deepEqual(resource.getLabels(), expectedLabels);
+       assert.equal(resource.type, 'default');
+       assert.equal(Object.keys(resource.labels).length, 1);
+       assert.deepEqual(resource.labels, expectedLabels);
      });
 });

From f3796a293390516c5ac540a8c90caf347b81c43b Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Mon, 26 Nov 2018 11:44:55 -0800
Subject: [PATCH 4/6] fix reviews

---
 .../opencensus-core/src/resource/resource.ts  |  9 ++++----
 .../opencensus-core/test/test-resource.ts     | 23 +++++--------------
 2 files changed, 10 insertions(+), 22 deletions(-)

diff --git a/packages/opencensus-core/src/resource/resource.ts b/packages/opencensus-core/src/resource/resource.ts
index 600e7c766..836a3d1df 100644
--- a/packages/opencensus-core/src/resource/resource.ts
+++ b/packages/opencensus-core/src/resource/resource.ts
@@ -69,7 +69,7 @@ export class CoreResource {
   /**
    * Creates a resource type from the OC_RESOURCE_TYPE environment variable.
    *
-   * <p>OC_RESOURCE_TYPE: A string that describes the type of the resource
+   * OC_RESOURCE_TYPE: A string that describes the type of the resource
    * prefixed by a domain namespace, e.g. “kubernetes.io/container”.
    *
    * @param  {string} rawEnvType The resource type.
@@ -88,7 +88,7 @@ export class CoreResource {
   /**
    * Creates a label map from the OC_RESOURCE_LABELS environment variable.
    *
-   * <p>OC_RESOURCE_LABELS: A comma-separated list of labels describing the
+   * OC_RESOURCE_LABELS: A comma-separated list of labels describing the
    * source in more detail, e.g. “key1=val1,key2=val2”. Domain names and paths
    * are accepted as label keys. Values may be quoted or unquoted in general. If
    * a value contains whitespaces, =, or " characters, it must always be quoted.
@@ -102,14 +102,13 @@ export class CoreResource {
     const labels: {[key: string]: string;} = {};
     if (rawEnvLabels) {
       const rawLabels: string[] = rawEnvLabels.split(this.COMMA_SEPARATOR, -1);
-      let key, value;
       for (const rawLabel of rawLabels) {
         const keyValuePair: string[] =
             rawLabel.split(this.LABEL_KEY_VALUE_SPLITTER, -1);
         if (keyValuePair.length !== 2) {
           continue;
         }
-        [key, value] = keyValuePair;
+        let [key, value] = keyValuePair;
         // Leading and trailing whitespaces are trimmed.
         key = key.trim();
         value = value.trim().split('^"|"$').join('');
@@ -144,7 +143,7 @@ export class CoreResource {
     }
     return {
       type: resource.type || otherResource.type,
-      labels: Object.assign(otherResource.labels, resource.labels)
+      labels: Object.assign({}, otherResource.labels, resource.labels)
     };
   }
 
diff --git a/packages/opencensus-core/test/test-resource.ts b/packages/opencensus-core/test/test-resource.ts
index 0d79bceea..77e69e4e9 100644
--- a/packages/opencensus-core/test/test-resource.ts
+++ b/packages/opencensus-core/test/test-resource.ts
@@ -23,23 +23,6 @@ process.env.OC_RESOURCE_LABELS =
 import {CoreResource} from '../src/resource/resource';
 import {Resource} from '../src/resource/types';
 
-const DEFAULT_RESOURCE: Resource = {
-  type: null,
-  labels: {}
-};
-const DEFAULT_RESOURCE_1: Resource = {
-  type: 'default',
-  labels: {'a': '100'}
-};
-const RESOURCE_1: Resource = {
-  type: 't1',
-  labels: {'a': '1', 'b': '2'}
-};
-const RESOURCE_2: Resource = {
-  type: 't2',
-  labels: {'a': '1', 'b': '3', 'c': '4'}
-};
-
 describe('Resource()', () => {
   afterEach(() => {
     delete process.env.OC_RESOURCE_TYPE;
@@ -62,6 +45,12 @@ describe('Resource()', () => {
 });
 
 describe('mergeResources()', () => {
+  const DEFAULT_RESOURCE: Resource = {type: null, labels: {}};
+  const DEFAULT_RESOURCE_1: Resource = {type: 'default', labels: {'a': '100'}};
+  const RESOURCE_1: Resource = {type: 't1', labels: {'a': '1', 'b': '2'}};
+  const RESOURCE_2:
+      Resource = {type: 't2', labels: {'a': '1', 'b': '3', 'c': '4'}};
+
   it('merge resources with default, resource1', () => {
     const resources: Resource[] = [DEFAULT_RESOURCE, RESOURCE_1];
     const resource = CoreResource.mergeResources(resources);

From bc169fe86fbff75697accdc5ddff8d2cf720ca73 Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Mon, 26 Nov 2018 14:38:16 -0800
Subject: [PATCH 5/6] remove null from Resource: type

---
 packages/opencensus-core/src/resource/resource.ts | 7 +++++++
 packages/opencensus-core/src/resource/types.ts    | 2 +-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/packages/opencensus-core/src/resource/resource.ts b/packages/opencensus-core/src/resource/resource.ts
index 836a3d1df..b3149a948 100644
--- a/packages/opencensus-core/src/resource/resource.ts
+++ b/packages/opencensus-core/src/resource/resource.ts
@@ -27,8 +27,15 @@ import {Resource} from './types';
 export class CoreResource {
   // Type, label keys, and label values should not exceed 256 characters.
   private static readonly MAX_LENGTH = 255;
+
+  /**
+   * OC_RESOURCE_LABELS is a comma-separated list of labels (key and value are
+   * separated by '=') describing the source in more detail, e.g.
+   * “key1=val1,key2=val2”.
+   */
   private static readonly COMMA_SEPARATOR = ',';
   private static readonly LABEL_KEY_VALUE_SPLITTER = '=';
+
   private static readonly ENV_TYPE =
       CoreResource.parseResourceType(process.env.OC_RESOURCE_TYPE);
   private static readonly ENV_LABEL_MAP =
diff --git a/packages/opencensus-core/src/resource/types.ts b/packages/opencensus-core/src/resource/types.ts
index 8a39994e2..d64742c4c 100644
--- a/packages/opencensus-core/src/resource/types.ts
+++ b/packages/opencensus-core/src/resource/types.ts
@@ -19,7 +19,7 @@ export interface Resource {
   /**
    * An optional string which describes a well-known type of resource.
    */
-  readonly type: string|null;
+  readonly type: string;
 
   /**
    * A dictionary of labels with string keys and values that provide information

From 46df0d49a7fd0bc0cbcf4b8caccacd818ba2b5bd Mon Sep 17 00:00:00 2001
From: Mayur Kale <mayurkale@google.com>
Date: Mon, 26 Nov 2018 16:35:14 -0800
Subject: [PATCH 6/6] Add interface for Labels

---
 .../opencensus-core/src/resource/resource.ts   | 18 ++++++++----------
 packages/opencensus-core/src/resource/types.ts |  5 ++++-
 packages/opencensus-core/test/test-resource.ts | 18 ++++++++----------
 3 files changed, 20 insertions(+), 21 deletions(-)

diff --git a/packages/opencensus-core/src/resource/resource.ts b/packages/opencensus-core/src/resource/resource.ts
index b3149a948..03e4c3acf 100644
--- a/packages/opencensus-core/src/resource/resource.ts
+++ b/packages/opencensus-core/src/resource/resource.ts
@@ -15,7 +15,8 @@
  */
 
 import {StringUtils} from '../internal/string-utils';
-import {Resource} from './types';
+
+import {Labels, Resource} from './types';
 
 /**
  * Resource represents a resource, which capture identifying information about
@@ -28,12 +29,10 @@ export class CoreResource {
   // Type, label keys, and label values should not exceed 256 characters.
   private static readonly MAX_LENGTH = 255;
 
-  /**
-   * OC_RESOURCE_LABELS is a comma-separated list of labels (key and value are
-   * separated by '=') describing the source in more detail, e.g.
-   * “key1=val1,key2=val2”.
-   */
+  // OC_RESOURCE_LABELS is a comma-separated list of labels.
   private static readonly COMMA_SEPARATOR = ',';
+
+  // OC_RESOURCE_LABELS contains key value pair separated by '='.
   private static readonly LABEL_KEY_VALUE_SPLITTER = '=';
 
   private static readonly ENV_TYPE =
@@ -102,11 +101,10 @@ export class CoreResource {
    *
    * @param {string} rawEnvLabels The resource labels as a comma-seperated list
    * of key/value pairs.
-   * @returns {[key: string]: string} The sanitized resource labels.
+   * @returns {Labels} The sanitized resource labels.
    */
-  private static parseResourceLabels(rawEnvLabels: string):
-      {[key: string]: string;} {
-    const labels: {[key: string]: string;} = {};
+  private static parseResourceLabels(rawEnvLabels: string): Labels {
+    const labels: Labels = {};
     if (rawEnvLabels) {
       const rawLabels: string[] = rawEnvLabels.split(this.COMMA_SEPARATOR, -1);
       for (const rawLabel of rawLabels) {
diff --git a/packages/opencensus-core/src/resource/types.ts b/packages/opencensus-core/src/resource/types.ts
index d64742c4c..d32dba8ef 100644
--- a/packages/opencensus-core/src/resource/types.ts
+++ b/packages/opencensus-core/src/resource/types.ts
@@ -25,5 +25,8 @@ export interface Resource {
    * A dictionary of labels with string keys and values that provide information
    * about the entity.
    */
-  readonly labels: {[key: string]: string;};
+  readonly labels: Labels;
 }
+
+/** Labels are maps of keys -> values */
+export interface Labels { [key: string]: string; }
diff --git a/packages/opencensus-core/test/test-resource.ts b/packages/opencensus-core/test/test-resource.ts
index 77e69e4e9..e216c96a1 100644
--- a/packages/opencensus-core/test/test-resource.ts
+++ b/packages/opencensus-core/test/test-resource.ts
@@ -21,10 +21,10 @@ process.env.OC_RESOURCE_LABELS =
     'k8s.io/pod/name="pod-xyz-123",k8s.io/container/name="c1",k8s.io/namespace/name="default"';
 
 import {CoreResource} from '../src/resource/resource';
-import {Resource} from '../src/resource/types';
+import {Resource, Labels} from '../src/resource/types';
 
 describe('Resource()', () => {
-  afterEach(() => {
+  after(() => {
     delete process.env.OC_RESOURCE_TYPE;
     delete process.env.OC_RESOURCE_LABELS;
   });
@@ -32,7 +32,7 @@ describe('Resource()', () => {
   it('should return resource information from environment variables', () => {
     const resource = CoreResource.createFromEnvironmentVariables();
     const actualLabels = resource.labels;
-    const expectedLabels: {[key: string]: string} = {
+    const expectedLabels: Labels = {
       'k8s.io/container/name': '"c1"',
       'k8s.io/namespace/name': '"default"',
       'k8s.io/pod/name': '"pod-xyz-123"'
@@ -54,7 +54,7 @@ describe('mergeResources()', () => {
   it('merge resources with default, resource1', () => {
     const resources: Resource[] = [DEFAULT_RESOURCE, RESOURCE_1];
     const resource = CoreResource.mergeResources(resources);
-    const expectedLabels: {[key: string]: string} = {'a': '1', 'b': '2'};
+    const expectedLabels: Labels = {'a': '1', 'b': '2'};
 
     assert.equal(resource.type, 't1');
     assert.equal(Object.keys(resource.labels).length, 2);
@@ -64,7 +64,7 @@ describe('mergeResources()', () => {
   it('merge resources with default, resource1, resource2 = null', () => {
     const resources: Resource[] = [DEFAULT_RESOURCE, RESOURCE_1, null];
     const resource = CoreResource.mergeResources(resources);
-    const expectedLabels: {[key: string]: string} = {'a': '1', 'b': '2'};
+    const expectedLabels: Labels = {'a': '1', 'b': '2'};
 
     assert.equal(resource.type, 't1');
     assert.equal(Object.keys(resource.labels).length, 2);
@@ -74,8 +74,7 @@ describe('mergeResources()', () => {
   it('merge resources with default, resource1 = null, resource2', () => {
     const resources: Resource[] = [DEFAULT_RESOURCE, null, RESOURCE_2];
     const resource = CoreResource.mergeResources(resources);
-    const expectedLabels:
-        {[key: string]: string} = {'a': '1', 'b': '3', 'c': '4'};
+    const expectedLabels: Labels = {'a': '1', 'b': '3', 'c': '4'};
 
     assert.equal(resource.type, 't2');
     assert.equal(Object.keys(resource.labels).length, 3);
@@ -85,8 +84,7 @@ describe('mergeResources()', () => {
   it('merge resources with default1, resource1, resource2', () => {
     const resources: Resource[] = [DEFAULT_RESOURCE_1, RESOURCE_1, RESOURCE_2];
     const resource = CoreResource.mergeResources(resources);
-    const expectedLabels:
-        {[key: string]: string} = {'a': '100', 'b': '2', 'c': '4'};
+    const expectedLabels: Labels = {'a': '100', 'b': '2', 'c': '4'};
 
     assert.equal(resource.type, 'default');
     assert.equal(Object.keys(resource.labels).length, 3);
@@ -97,7 +95,7 @@ describe('mergeResources()', () => {
      () => {
        const resources: Resource[] = [DEFAULT_RESOURCE_1, undefined, undefined];
        const resource = CoreResource.mergeResources(resources);
-       const expectedLabels: {[key: string]: string} = {'a': '100'};
+       const expectedLabels: Labels = {'a': '100'};
 
        assert.equal(resource.type, 'default');
        assert.equal(Object.keys(resource.labels).length, 1);