feat(parameters): add appconfig provider with types

Author: shdq

packages/parameters/src/AppConfigProvider.ts

@@ -0,0 +1,111 @@
+import { BaseProvider, DEFAULT_PROVIDERS } from 'BaseProvider';
+import {
+  AppConfigDataClient,
+  StartConfigurationSessionCommand,
+  GetLatestConfigurationCommand,
+} from '@aws-sdk/client-appconfigdata';
+import type {
+  StartConfigurationSessionCommandInput,
+  GetLatestConfigurationCommandInput,
+} from '@aws-sdk/client-appconfigdata';
+import type { AppConfigGetOptionsInterface } from './types/AppConfigProvider';
+
+class AppConfigProvider extends BaseProvider {
+  public client: AppConfigDataClient;
+  private application?: string;
+  private environment?: string;
+  private token: string | undefined;
+
+  /**
+   * It initializes the AppConfigProvider class with an optional set of options like region: 'us-west-1'.
+   * *
+   * @param {AppConfigDataClientConfig} options
+   */
+  public constructor(options: AppConfigGetOptionsInterface = {}) {
+    super();
+    this.client = new AppConfigDataClient(options.config || {});
+    this.environment = options.environment;
+    this.application = options.application || 'service_undefined'; // TODO: get value from ENV VARIABLES
+  }
+
+  /**
+   * Retrieve a parameter value from AWS App config.
+   *
+   * @param {string} name - Name of the configuration
+   * @param {StartConfigurationSessionCommandInput} [sdkOptions] - SDK options to propagate to `StartConfigurationSession` API call
+   * @returns {Promise<string | undefined>}
+   */
+  protected async _get(
+    name: string,
+    options?: AppConfigGetOptionsInterface
+  ): Promise<string | undefined> {
+    /**
+     * The new AppConfig APIs require two API calls to return the configuration
+     * First we start the session and after that we retrieve the configuration
+     * We need to store the token to use in the next execution
+     **/
+    if (!this.token) {
+      const sessionOptions: StartConfigurationSessionCommandInput = {
+        ConfigurationProfileIdentifier: name,
+        EnvironmentIdentifier: this.environment,
+        ApplicationIdentifier: this.application,
+      };
+      if (options && options.hasOwnProperty('sdkOptions')) {
+        Object.assign(sessionOptions, options.sdkOptions);
+      }
+
+      const sessionCommand = new StartConfigurationSessionCommand(
+        sessionOptions
+      );
+
+      const session = await this.client.send(sessionCommand);
+      this.token = session.InitialConfigurationToken;
+    }
+
+    const getConfigurationCommand = new GetLatestConfigurationCommand({
+      ConfigurationToken: this.token,
+    });
+    const response = await this.client.send(getConfigurationCommand);
+
+    //  Should we cache and flush the token after 24 hours?
+    //  NextPollConfigurationToken expires in 24 hours after the last request and causes `BadRequestException`
+    this.token = response.NextPollConfigurationToken;
+
+    const configuration = response.Configuration;
+
+    // should we convert Uint8Array to string?
+    const utf8decoder = new TextDecoder();
+    const value = configuration ? utf8decoder.decode(configuration) : undefined;
+
+    return value;
+  }
+
+  /**
+   * Retrieving multiple parameter values is not supported with AWS App Config Provider.
+   *
+   * @throws Not Implemented Error.
+   */
+  protected async _getMultiple(
+    path: string,
+    sdkOptions?: Partial<GetLatestConfigurationCommandInput>
+  ): Promise<Record<string, string | undefined>> {
+    return this._notImplementedError();
+  }
+
+  private _notImplementedError(): never {
+    throw new Error('Not Implemented');
+  }
+}
+
+const getAppConfig = (
+  name: string,
+  options?: AppConfigGetOptionsInterface
+): Promise<undefined | string | Record<string, unknown>> => {
+  if (!DEFAULT_PROVIDERS.hasOwnProperty('appconfig')) {
+    DEFAULT_PROVIDERS.appconfig = new AppConfigProvider(options);
+  }
+
+  return DEFAULT_PROVIDERS.appconfig.get(name, options);
+};
+
+export { AppConfigProvider, getAppConfig };

packages/parameters/src/types/AppConfigProvider.ts

@@ -0,0 +1,18 @@
+import type { StartConfigurationSessionCommandInput, AppConfigDataClientConfig } from '@aws-sdk/client-appconfigdata';
+import type { GetOptionsInterface } from 'types/BaseProvider';
+
+/**
+ * Options for the AppConfigProvider get method.
+ *
+ * @interface AppConfigGetOptionsInterface
+ * @extends {GetOptionsInterface}
+ * @property {Partial<StartConfigurationSessionCommandInput>} sdkOptions - Options for the AWS SDK.
+ */
+interface AppConfigGetOptionsInterface extends Omit<GetOptionsInterface, 'sdkOptions'> {
+  application?: string
+  config?: AppConfigDataClientConfig
+  environment?: string
+  sdkOptions?: Partial<StartConfigurationSessionCommandInput>
+}
+
+export { AppConfigGetOptionsInterface };