refactor: privatize ZpagesExporter#getAllTraces (#43)

Author: kjin

packages/opencensus-exporter-zpages/package.json

@@ -43,6 +43,7 @@
     "@types/extend": "^3.0.0",
     "@types/mocha": "^2.2.48",
     "@types/node": "^9.4.7",
+    "axios": "^0.18.0",
     "gts": "^0.5.4",
     "mocha": "^5.0.4",
     "nyc": "11.6.0",

packages/opencensus-exporter-zpages/src/zpages-frontend/controllers/traceconfigz.controller.ts

@@ -13,49 +13,15 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-
-import * as tracing from '@opencensus/nodejs';
-import {classes} from '@opencensus/opencensus-core';
 import * as express from 'express';
-
-import {ZpagesExporter} from '../../zpages';
-
 import {TraceConfigzPageHandler} from './../page-handlers/traceconfigz.page-handler';
 
-type SaveQuery = {
-  change: string,
-  samplingprobability: number
-};
-
 /**
- * Loads the Trace config page
- * @param req request data
- * @param res response data
+ * An Express middleware that renders the TraceConfigz view.
  */
-export const home = (req: express.Request, res: express.Response) => {
+export function createTraceConfigzHandler(): express.Handler {
   const html = new TraceConfigzPageHandler();
-  if (req.query) {
-    saveChanges(req.query);
-  }
-  res.send(html.emitHtml());
-};
-
-/**
- * Saves changes made to Trace config page
- * @param query request query
- */
-const saveChanges = (query: SaveQuery) => {
-  /** restore the config to default */
-  if (query.change === 'restore_default') {
-    const exporter = tracing.exporter as ZpagesExporter;
-    tracing.tracer.sampler =
-        new classes.Sampler().probability(exporter.defaultConfig.samplingRate);
-    return;
-  }
-
-  /** change the sampling probability value */
-  if (query.samplingprobability) {
-    tracing.tracer.sampler =
-        new classes.Sampler().probability(query.samplingprobability);
-  }
-};
+  return (req: express.Request, res: express.Response) => {
+    res.send(html.emitHtml(req.query, req.query.json === '1'));
+  };
+}

packages/opencensus-exporter-zpages/src/zpages-frontend/controllers/tracez.controller.ts

@@ -14,11 +14,19 @@
  * limitations under the License.
  */
 
+import {types} from '@opencensus/opencensus-core';
 import * as express from 'express';
 
 import {TracezPageHandler} from './../page-handlers/tracez.page-handler';
 
-export const home = (req: express.Request, res: express.Response) => {
-  const html = new TracezPageHandler();
-  res.send(html.emitHtml(req.query));
-};
+/**
+ * Creates an Express middleware that renders the Tracez view.
+ * @param traceMap A span data store.
+ */
+export function createTracezHandler(traceMap: Map<string, types.Span[]>):
+    express.Handler {
+  return (req: express.Request, res: express.Response) => {
+    const html = new TracezPageHandler(traceMap);
+    res.send(html.emitHtml(req.query, req.query.json === '1'));
+  };
+}

packages/opencensus-exporter-zpages/src/zpages-frontend/page-handlers/traceconfigz.page-handler.ts

@@ -15,47 +15,89 @@
  */
 
 import * as tracing from '@opencensus/nodejs';
-import {types} from '@opencensus/opencensus-core';
+import {classes, types} from '@opencensus/opencensus-core';
 
 import {ZpagesExporter} from '../../zpages';
 
 const ejs = require('ejs');
 
+export interface TraceConfigzParams {
+  change: string;
+  samplingprobability: number;
+}
+
+export interface TraceConfigzData {
+  defaultConfig: {samplingRate: number};
+  samplingProbability: number;
+}
+
 export class TraceConfigzPageHandler {
+  /** Configuration defaults. Currently just the default sampling rate. */
+  private defaultConfig: {samplingRate: number;};
+
   /**
    * Generate Zpages Trace Config HTML Page
+   * @param params The incoming request query.
+   * @param json If true, JSON will be emitted instead. Used for testing only.
    * @returns output HTML
    */
-  emitHtml(): string {
+  emitHtml(params: Partial<TraceConfigzParams>, json: boolean): string {
+    if (params) {
+      this.saveChanges(params);
+    }
+
+    if (!this.defaultConfig) {
+      this.defaultConfig = {
+        samplingRate: TraceConfigzPageHandler.extractSamplingProbability()
+      };
+    }
+
     /** template HTML */
     const traceConfigzFile =
         ejs.fileLoader(__dirname + '/../templates/traceconfigz.ejs', 'utf8');
     /** EJS render options */
     const options = {delimiter: '?'};
-    /** Zpages exporter object from current instance */
-    const exporter = tracing.exporter as ZpagesExporter;
     /** Current sampling rate  */
-    const samplingProbability = this.extractSamplingProbability();
+    const samplingProbability =
+        TraceConfigzPageHandler.extractSamplingProbability();
 
-    /**
-     * Checks if the current export has a defaultConfig, otherwise creates one
-     */
-    if (!exporter.defaultConfig) {
-      exporter.defaultConfig = {samplingRate: samplingProbability} as
-          types.TracerConfig;
+    /** Rendering the HTML table summary */
+    const renderParams: TraceConfigzData = {
+      defaultConfig: this.defaultConfig,
+      samplingProbability
+    };
+    if (json) {
+      return JSON.stringify(renderParams, null, 2);
+    } else {
+      return ejs.render(traceConfigzFile, renderParams, options);
     }
+  }
 
-    /** Rendering the HTML table summary */
-    return ejs.render(
-        traceConfigzFile,
-        {defaultConfig: exporter.defaultConfig, samplingProbability}, options);
+  /**
+   * Saves changes made to Trace config page
+   * @param query request query
+   */
+  private saveChanges(query: Partial<TraceConfigzParams>): void {
+    /** restore the config to default */
+    if (query.change === 'restore_default') {
+      const exporter = tracing.exporter as ZpagesExporter;
+      tracing.tracer.sampler =
+          new classes.Sampler().probability(this.defaultConfig!.samplingRate);
+      return;
+    }
+
+    /** change the sampling probability value */
+    if (query.samplingprobability) {
+      tracing.tracer.sampler =
+          new classes.Sampler().probability(query.samplingprobability);
+    }
   }
 
   /**
    * Gets the sample rate from tracer instance
    * @returns the sampling probability
    */
-  private extractSamplingProbability(): number {
+  private static extractSamplingProbability(): number {
     /**  */
     const samplingProbability = tracing.tracer.sampler.description;
     if (samplingProbability === 'always') {