Add KubernetesObjectApi

Add generic object API that dynamically determines endpoint based on
the provided spec.  Add KubernetesObjectApi to index exports.  Provide
tests and example usage.

Closes #375

Author: David Dooling

examples/typescript/apply/apply-example.ts

@@ -0,0 +1,43 @@
+import * as k8s from '@kubernetes/client-node';
+import * as fs from 'fs';
+import * as yaml from 'js-yaml';
+import { promisify } from 'util';
+
+/**
+ * Replicate the functionality of `kubectl apply`.  That is, create the resources defined in the `specFile` if they do
+ * not exist, patch them if they do exist.
+ *
+ * @param specPath File system path to a YAML Kubernetes spec.
+ * @return Array of resources created
+ */
+export async function apply(specPath: string): Promise<k8s.KubernetesObject[]> {
+    const kc = new k8s.KubeConfig();
+    kc.loadFromDefault();
+    const client = k8s.KubernetesObjectApi.makeApiClient(kc);
+    const fsReadFileP = promisify(fs.readFile);
+    const specString = await fsReadFileP(specPath, 'utf8');
+    const specs: k8s.KubernetesObject[] = yaml.safeLoadAll(specString);
+    const validSpecs = specs.filter((s) => s && s.kind && s.metadata);
+    const created: k8s.KubernetesObject[] = [];
+    for (const spec of validSpecs) {
+        // this is to convince the old version of TypeScript that metadata exists even though we already filtered specs
+        // without metadata out
+        spec.metadata = spec.metadata || {};
+        spec.metadata.annotations = spec.metadata.annotations || {};
+        delete spec.metadata.annotations['kubectl.kubernetes.io/last-applied-configuration'];
+        spec.metadata.annotations['kubectl.kubernetes.io/last-applied-configuration'] = JSON.stringify(spec);
+        try {
+            // try to get the resource, if it does not exist an error will be thrown and we will end up in the catch
+            // block.
+            await client.read(spec);
+            // we got the resource, so it exists, so patch it
+            const response = await client.patch(spec);
+            created.push(response.body);
+        } catch (e) {
+            // we did not get the resource, so it does not exist, so create it
+            const response = await client.create(spec);
+            created.push(response.body);
+        }
+    }
+    return created;
+}

src/index.ts

@@ -10,3 +10,4 @@ export * from './yaml';
 export * from './log';
 export * from './informer';
 export * from './top';
+export * from './object';