feat(backends): @kubernetes/client-node (#394)

Experimental support for a @kubernetes/client-node based backend.

examples/kubernetes-client-node.js

@@ -0,0 +1,82 @@
+/* eslint no-console:0 */
+//
+// Demonstrate how to use @kubernetes/client-node as a backend.
+//
+const k8s = require('@kubernetes/client-node')
+
+const Client = require('..').Client
+const ClientNodeBackend = require('../lib/backends/kubernetes-client-node')
+
+const deploymentManifest = require('./nginx-deployment.json')
+
+async function main () {
+  try {
+    const kubeconfig = new k8s.KubeConfig()
+    kubeconfig.loadFromDefault()
+
+    const backend = new ClientNodeBackend({ client: k8s, kubeconfig })
+    const client = new Client({ backend, version: '1.10' })
+
+    //
+    // Get all the Namespaces.
+    //
+    const namespaces = (await client.api.v1.namespaces.get()).body.items.map(namespace => ({
+      name: namespace.metadata.name,
+      status: namespace.status
+    }))
+    console.log('Namespaces:', JSON.stringify(namespaces, null, 2))
+
+    //
+    // Create a new Deployment.
+    //
+    const create = await client.apis.apps.v1.namespaces('default').deployments.post({ body: deploymentManifest })
+    console.log('Create:', create.body)
+
+    //
+    // Fetch the Deployment we just created.
+    //
+    const deployment = await client.apis.apps.v1.namespaces('default').deployments(deploymentManifest.metadata.name).get()
+    console.log('Deployment: ', deployment.body)
+
+    //
+    // Change the Deployment Replica count to 10
+    //
+
+    const replica = {
+      spec: {
+        replicas: 10
+      }
+    }
+
+    const replicaModify = await client.apis.apps.v1.namespaces('default').deployments(deploymentManifest.metadata.name).patch({ body: replica })
+    console.log('Replica Modification: ', replicaModify)
+
+    //
+    // Modify the image tag
+    //
+    const newImage = {
+      spec: {
+        template: {
+          spec: {
+            containers: [{
+              name: 'nginx',
+              image: 'nginx:1.8.1'
+            }]
+          }
+        }
+      }
+    }
+    const imageSet = await client.apis.apps.v1.namespaces('default').deployments(deploymentManifest.metadata.name).patch({ body: newImage })
+    console.log('New Image: ', imageSet)
+
+    //
+    // Remove the Deployment we created.
+    //
+    const removed = await client.apis.apps.v1.namespaces('default').deployments(deploymentManifest.metadata.name).delete()
+    console.log('Removed: ', removed)
+  } catch (err) {
+    console.error('Error:', err.message)
+  }
+}
+
+main()

lib/backends/kubernetes-client-node.js

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+'use strict'
+
+const pascalcase = require('pascalcase')
+
+//
+// https://github.com/kubernetes-client/javascript
+//
+class ClientNodeBackend {
+  constructor (options) {
+    this.client = options.client
+    this.kubeconfig = options.kubeconfig
+    this.apiClients = { }
+  }
+
+  _getApiClient (tag) {
+    //
+    // API type is a snake_case CamelCase amalgamation. E.g., Core_v1Api
+    //
+    const apiType = tag.charAt(0).toUpperCase() + tag.slice(1) + 'Api'
+    if (!(apiType in this.apiClients)) {
+      this.apiClients[apiType] = this.kubeconfig.makeApiClient(this.client[apiType])
+    }
+    return this.apiClients[apiType]
+  }
+
+  http (options) {
+    const pathItemObject = options.pathItemObject
+    const operationObject = pathItemObject[options.method.toLowerCase()]
+    const tag = operationObject.tags[0]
+
+    const apiClient = this._getApiClient(tag)
+
+    //
+    // In older Kubernetes API OpenAPI specifications the Operation IDs include
+    // the tag, but in newer versions (including the ones used to generate
+    // @kubernetes/client-node), the tag is absent.
+    //
+    // Support older versions of the Swagger specifications by removing the tag
+    // part.
+    //
+    const method = operationObject.operationId.replace(pascalcase(tag), '')
+
+    //
+    // @kubernetes/client-node methods take parameters in the order the OpenAPI
+    // specification declares them.
+    //
+    const parameterObjects = (pathItemObject.parameters || []).concat(operationObject.parameters || [])
+    const orderedParameterObjects = parameterObjects
+      .filter(parameterObject => parameterObject.required)
+      .concat(parameterObjects
+        .filter(parameterObject => !parameterObject.required))
+
+    //
+    // Older versions of the Kubernetes API OpenAPI specifications requires body
+    // for _some_ delete operations (e.g., deleteNamespacedDeployment). The API
+    // does not actually require it and newer specifications remove the
+    // requirement. Try to Workaround this issue by adding an empty body to
+    // @kubernetes/client-node calls.
+    //
+    let body = options.body
+    if (options.method.toLowerCase() === 'delete' && !body) {
+      body = {}
+    }
+
+    const parameters = Object.assign(
+      { body },
+      options.pathnameParameters,
+      options.qs,
+      options.parameters)
+    const args = orderedParameterObjects.reduce((acc, operationParameter) => {
+      const name = operationParameter.name
+      if (name in parameters) acc.push(parameters[name])
+      else acc.push(undefined)
+      return acc
+    }, [])
+
+    return apiClient[method].apply(apiClient, args)
+      .then(res => {
+        res.statusCode = res.response.statusCode
+        return res
+      })
+      .catch(err => {
+        if (!err.body) throw err
+        const error = new Error(err.body.message)
+        // .code is backwards compatible with pre-5.0.0 code.
+        error.code = err.response.statusCode
+        error.statusCode = err.response.statusCode
+        throw error
+      })
+  }
+}
+
+module.exports = ClientNodeBackend

lib/backends/kubernetes-client-node.test.js

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+'use strict'
+/* eslint-env mocha */
+
+const { expect } = require('chai')
+const sinon = require('sinon')
+
+const ClientNodeBackend = require('./kubernetes-client-node')
+
+describe('lib.backends.kubernetes-client-node', () => {
+  it('calls the expected method', done => {
+    const fakeK8sClient = { Core_v1Api: 'foo' }
+    const fakeKubeconfig = {
+      makeApiClient: sinon.spy(() => {
+        return {
+          getStuff: (bar, foo) => {
+            return new Promise((resolve, reject) => {
+              expect(bar).to.equal('bar')
+              expect(foo).to.equal('foo')
+              resolve({
+                response: {
+                  statusCode: 200
+                }
+              })
+            })
+          }
+        }
+      })
+    }
+
+    const options = {
+      method: 'GET',
+      pathnameParameters: {
+        foo: 'foo'
+      },
+      parameters: {
+        bar: 'bar'
+      },
+      pathItemObject: {
+        get: {
+          operationId: 'getStuff',
+          parameters: [{
+            name: 'foo'
+          }],
+          tags: ['core_v1']
+        },
+        parameters: [{
+          name: 'bar'
+        }]
+      }
+    }
+
+    const client = new ClientNodeBackend({
+      client: fakeK8sClient,
+      kubeconfig: fakeKubeconfig
+    })
+
+    client.http(options)
+      .then(res => done())
+      .catch(done)
+  })
+})