Add server-sent events for tests.

Author: johnsusek

README.md

@@ -209,6 +209,10 @@ This server exposes the following REST API's:
       }
       ``` 
 
+- **GET `/test_stream`**
+
+    This allows you to test a rule and get a [Server Sent Events](https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events) event stream back. Pass params `rule` (yaml string) and `options` (JSON string) to start receiving events.
+
 - **GET `/metadata/:type`**
 
     Returns metadata from elasticsearch related to elasalert's state. `:type` should be one of: elastalert_status, elastalert, elastalert_error, or silence. See [docs about the elastalert metadata index](https://elastalert.readthedocs.io/en/latest/elastalert_status.html).
@@ -217,6 +221,10 @@ This server exposes the following REST API's:
 
     Returns field mapping from elasticsearch for a given index. 
 
+- **GET `/search/:index`**
+
+    Performs elasticsearch query on behalf of the API. JSON body to this endpoint will become body of an ES search. 
+
 - **[WIP] GET `/config`**
 
     Gets the ElastAlert configuration from `config.yaml` in `elastalertPath` (from the config).

src/controllers/test/index.js

@@ -19,7 +19,7 @@ export default class TestController {
     });
   }
 
-  testRule(rule, options) {
+  testRule(rule, options, stream, response) {
     const self = this;
     let tempFileName = '~' + randomstring.generate() + '.temp';
     let tempFilePath = path.join(self.testFolder, tempFileName);
@@ -61,14 +61,25 @@ export default class TestController {
             });
 
             testProcess.stdout.on('data', function (data) {
+              if (stream) {
+                response.write('event: result\ndata: ' + data.toString() + '\n\n');
+              }
               stdoutLines.push(data.toString());
             });
 
             testProcess.stderr.on('data', function (data) {
+              if (stream) {
+                response.write('event: progress\ndata: ' + data.toString() + '\n\n');
+              }
               stderrLines.push(data.toString());
             });
 
             testProcess.on('exit', function (statusCode) {
+              if (stream) {
+                response.write('event: done\ndata: DONE\n\n');
+                response.end();
+              }
+
               if (statusCode === 0) {
                 if (options.format === 'json') {
                   resolve(stdoutLines.join(''));

src/handlers/test/stream.js

@@ -0,0 +1,59 @@
+import RouteLogger from '../../routes/route_logger';
+import {sendRequestError} from '../../common/errors/utils';
+import { RuleNotSendError, OptionsInvalidError} from '../../common/errors/test_request_errors';
+import Joi from 'joi';
+
+let logger = new RouteLogger('/test_stream', 'POST');
+
+const optionsSchema = Joi.object().keys({
+  testType: Joi.string().valid('all', 'schemaOnly', 'countOnly').default('all'),
+  days: Joi.number().min(1).default(1),
+  alert: Joi.boolean().default(false),
+  format: Joi.string().default(''),
+  maxResults: Joi.number().default(0)
+}).default();
+
+function analyzeRequest(request) {
+  if (!request.query.rule) {
+    return new RuleNotSendError();
+  }
+
+  const validationResult = Joi.validate(JSON.parse(request.query.options), optionsSchema);
+
+  if (validationResult.error) {
+    return new OptionsInvalidError(validationResult.error);
+  }
+
+  return request.body;
+}
+
+export default function testStreamGetHandler(request, response) {
+  /**
+   * @type {ElastalertServer}
+   */
+  let server = request.app.get('server');
+  let body = analyzeRequest(request);
+
+  try {
+    var options = JSON.parse(request.query.options);  
+  } catch (error) {
+    response.status(500).send();
+  }
+  
+  if (body.error) {
+    logger.sendFailed(body.error);
+    sendRequestError(response, body.error);
+  }
+
+  response.writeHead(200, {
+    'Content-Type': 'text/event-stream',
+    'Cache-Control': 'no-cache',
+    'Connection': 'keep-alive'
+  });
+
+  try {
+    server.testController.testRule(request.query.rule, options, true, response);
+  } catch (error) {
+    response.status(500).send();
+  }
+}

src/routes/routes.js

@@ -12,6 +12,7 @@ import templateGetHandler from '../handlers/templates/id/get';
 import templatePostHandler from '../handlers/templates/id/post';
 import templateDeleteHandler from '../handlers/templates/id/delete';
 import testPostHandler from '../handlers/test/post';
+import testStreamGetHandler from '../handlers/test/stream';
 import configGetHandler from '../handlers/config/get';
 import configPostHandler from '../handlers/config/post';
 import metadataHandler from '../handlers/metadata/get';
@@ -68,7 +69,13 @@ let routes = [
     path: 'test',
     method: 'POST',
     handler: testPostHandler
-  }, {
+  }, 
+  {
+    path: 'test_stream',
+    method: 'GET',
+    handler: testStreamGetHandler
+  },
+  {
     path: 'config',
     method: ['GET', 'POST'],
     handler: [configGetHandler, configPostHandler]