sample_circle.json

{
  "vcs_url" : "https://github.com/circleci/mongofinil",
  "build_url" : "https://circleci.com/gh/circleci/mongofinil/22",
  "build_num" : 22,
  "branch" : "master",
  "vcs_revision" : "1d231626ba1d2838e599c5c598d28e2306ad4e48",
  "committer_name" : "Allen Rohner",
  "committer_email" : "[email protected]",
  "subject" : "Don't explode when the system clock shifts backwards",
  "body" : "", 
  "why" : "github", 
  "dont_build" : null, 
  "queued_at" : "2013-02-12T21:33:30Z",
  "start_time" : "2013-02-12T21:33:38Z", 
  "stop_time" : "2013-02-12T21:34:01Z", 
  "build_time_millis" : 23505,
  "username" : "circleci",
  "reponame" : "mongofinil",
  "lifecycle" : "finished",
  "outcome" : "success", 
  "status" : "success", 
  "retry_of" : null, 
  "steps" : [ {
    "name" : "configure the build",
    "actions" : [ {
      "bash_command" : null,
      "run_time_millis" : 1646,
      "start_time" : "2013-02-12T21:33:38Z",
      "end_time" : "2013-02-12T21:33:39Z",
      "name" : "configure the build",
      "exit_code" : null,
      "type" : "infrastructure",
      "index" : 0,
      "status" : "success"
    } ] },
    {"name": "lein2 deps",
    "actions": [ {
      "bash_command" : "lein2 deps",
      "run_time_millis" : 7555,
      "start_time" : "2013-02-12T21:33:47Z",
      "messages" : [ ],
      "step" : 1,
      "exit_code" : 0,
      "end_time" : "2013-02-12T21:33:54Z",
      "index" : 0,
      "status" : "success",
      "type" : "dependencies",
      "source" : "inference",
      "failed" : null
    } ] },
    {"name" : "lein2 trampoline midje",
    "actions" : [ {
      "bash_command" : "lein2 trampoline midje",
      "run_time_millis" : 2310,
      "continue" : null,
      "parallel" : true,
      "start_time" : "2013-02-12T21:33:59Z",
      "name" : "lein2 trampoline midje",
      "messages" : [ ],
      "step" : 6,
      "exit_code" : 1,
      "end_time" : "2013-02-12T21:34:01Z",
      "index" : 0,
      "status" : "failed",
      "timedout" : null,
      "infrastructure_fail" : null,
      "type" : "test",
      "source" : "inference",
      "failed" : true
    } ]
  } ]
}

wt_hack.js

var MongoClient = require('mongodb').MongoClient;

/**
 * After the data is inserted it returs the count of succes / failure among all stored build data
 */
function showStats(db, done) {
  db.collection('builds').aggregate([{
    $group: {
        _id: "$outcome",
        count: {$sum: 1}
        },
 }], function(err, result) {
   if (err) {
     done(err, 'Saved but unable to aggregate');
   }
  done(null, result); 
 });
}

module.exports = function (ctx, done) {
  MongoClient.connect(ctx.data.MONGO_URL, function (err, db) {
    if (err) {
      done(err);
    }
    const buildsCollection = db.collection('builds');
    buildsCollection.insertOne(JSON.parse(ctx.body_raw), function (insertErr, result){
      if (insertErr)   {
        done(insertErr, 'Unable to insert build record');
      }
      showStats(db, done);
    });

  });
}

To use the tasks access this url: https://wt-3c4d6e49c62a7db180a095900783ffc5-0.run.webtask.io/hello