Add initial client for repository properties

src/feature-flags/properties.ts

@@ -0,0 +1,84 @@
+import { getApiClient } from "../api-client";
+import { Logger } from "../logging";
+import { RepositoryNwo } from "../repository";
+
+/**
+ * Enumerates repository property names that have some meaning to us.
+ */
+export enum RepositoryPropertyName {}
+
+/**
+ * A repository property has a name and a value.
+ */
+export interface RepositoryProperty {
+  property_name: string;
+  value: string;
+}
+
+/**
+ * The API returns a list of `RepositoryProperty` objects.
+ */
+type GitHubPropertiesResponse = RepositoryProperty[];
+
+/**
+ * A partial mapping from `RepositoryPropertyName` to values.
+ */
+export type RepositoryProperties = Partial<
+  Record<RepositoryPropertyName, string>
+>;
+
+/**
+ * Retrieves all known repository properties from the API.
+ *
+ * @param logger The logger to use.
+ * @param repositoryNwo Information about the repository for which to load properties.
+ * @returns Returns a partial mapping from `RepositoryPropertyName` to values.
+ */
+export async function loadPropertiesFromApi(
+  logger: Logger,
+  repositoryNwo: RepositoryNwo,
+): Promise<RepositoryProperties> {
+  try {
+    const response = await getApiClient().request(
+      "GET /repos/:owner/:repo/properties/values",
+      {
+        owner: repositoryNwo.owner,
+        repo: repositoryNwo.repo,
+      },
+    );
+    const remoteProperties = response.data as GitHubPropertiesResponse;
+
+    if (!Array.isArray(remoteProperties)) {
+      throw new Error(
+        `Expected repository properties API to return an array, but got: ${JSON.stringify(response.data)}`,
+      );
+    }
+
+    const knownProperties = new Set(Object.keys(RepositoryPropertyName));
+    const properties: RepositoryProperties = {};
+    for (const property of remoteProperties) {
+      if (property.property_name === undefined) {
+        throw new Error(
+          `Expected property object to have a 'property_name', but got: ${JSON.stringify(property)}`,
+        );
+      }
+
+      if (knownProperties.has(property.property_name)) {
+        properties[property.property_name] = property.value;
+      }
+    }
+
+    logger.debug("Loaded the following values for the repository properties:");
+    for (const [property, value] of Object.entries(properties).sort(
+      ([nameA], [nameB]) => nameA.localeCompare(nameB),
+    )) {
+      logger.debug(`  ${property}: ${value}`);
+    }
+
+    return properties;
+  } catch (e) {
+    throw new Error(
+      `Encountered an error while trying to determine repository properties: ${e}`,
+    );
+  }
+}