Show Ajax requests in performance bar

But first, rewrite the performance bar in Vue:

1. Remove the peek-host gem and replace it with existing code. This also allows
   us to include the host in the JSON response, rather than in the page HTML.
2. Leave the line profiler parts as here-be-dragons: nicer would be a separate
   endpoint for these, so we could use them on Ajax requests too.
3. The performance bar is too fiddly to rewrite right now, so apply the same
   logic to that.

Then, add features! All requests made through Axios are able to be tracked. To
keep a lid on memory usage, only the first two requests for a given URL are
tracked, though. Each request that's tracked has the same data as the initial
page load, with the exception of the performance bar and the line profiler, as
explained above.

11 files changed, 500 insertions, 67 deletions

diff --git a/app/assets/javascripts/dispatcher.js b/app/assets/javascripts/dispatcher.js
index 42ecc415173..72f21f13860 100644
--- a/app/assets/javascripts/dispatcher.js
+++ b/app/assets/javascripts/dispatcher.js
@@ -53,8 +53,12 @@ function initPageShortcuts(page) {
 
 function initGFMInput() {
   $('.js-gfm-input:not(.js-vue-textarea)').each((i, el) => {
-    const gfm = new GfmAutoComplete(gl.GfmAutoComplete && gl.GfmAutoComplete.dataSources);
-    const enableGFM = convertPermissionToBoolean(el.dataset.supportsAutocomplete);
+    const gfm = new GfmAutoComplete(
+      gl.GfmAutoComplete && gl.GfmAutoComplete.dataSources,
+    );
+    const enableGFM = convertPermissionToBoolean(
+      el.dataset.supportsAutocomplete,
+    );
     gfm.setup($(el), {
       emojis: true,
       members: enableGFM,
@@ -67,9 +71,9 @@ function initGFMInput() {
 }
 
 function initPerformanceBar() {
-  if (document.querySelector('#peek')) {
+  if (document.querySelector('#js-peek')) {
     import('./performance_bar')
-      .then(m => new m.default({ container: '#peek' })) // eslint-disable-line new-cap
+      .then(m => new m.default({ container: '#js-peek' })) // eslint-disable-line new-cap
       .catch(() => Flash('Error loading performance bar module'));
   }
 }
diff --git a/app/assets/javascripts/performance_bar.js b/app/assets/javascripts/performance_bar.js
deleted file mode 100644
index c22598ee665..00000000000
--- a/app/assets/javascripts/performance_bar.js
+++ /dev/null
@@ -1,57 +0,0 @@
-import $ from 'jquery';
-import 'vendor/peek';
-import 'vendor/peek.performance_bar';
-import { getParameterValues } from './lib/utils/url_utility';
-
-export default class PerformanceBar {
-  constructor(opts) {
-    if (!PerformanceBar.singleton) {
-      this.init(opts);
-      PerformanceBar.singleton = this;
-    }
-    return PerformanceBar.singleton;
-  }
-
-  init(opts) {
-    const $container = $(opts.container);
-    this.$lineProfileLink = $container.find('.js-toggle-modal-peek-line-profile');
-    this.$lineProfileModal = $('#modal-peek-line-profile');
-    this.initEventListeners();
-    this.showModalOnLoad();
-  }
-
-  initEventListeners() {
-    this.$lineProfileLink.on('click', e => this.handleLineProfileLink(e));
-    $(document).on('click', '.js-lineprof-file', PerformanceBar.toggleLineProfileFile);
-  }
-
-  showModalOnLoad() {
-    // When a lineprofiler query-string param is present, we show the line
-    // profiler modal upon page load
-    if (/lineprofiler/.test(window.location.search)) {
-      PerformanceBar.toggleModal(this.$lineProfileModal);
-    }
-  }
-
-  handleLineProfileLink(e) {
-    const lineProfilerParameter = getParameterValues('lineprofiler');
-    const lineProfilerParameterRegex = new RegExp(`lineprofiler=${lineProfilerParameter[0]}`);
-    const shouldToggleModal = lineProfilerParameter.length > 0 &&
-      lineProfilerParameterRegex.test(e.currentTarget.href);
-
-    if (shouldToggleModal) {
-      e.preventDefault();
-      PerformanceBar.toggleModal(this.$lineProfileModal);
-    }
-  }
-
-  static toggleModal($modal) {
-    if ($modal.length) {
-      $modal.modal('toggle');
-    }
-  }
-
-  static toggleLineProfileFile(e) {
-    $(e.currentTarget).parents('.peek-rblineprof-file').find('.data').toggle();
-  }
-}
diff --git a/app/assets/javascripts/performance_bar/components/detailed_metric.vue b/app/assets/javascripts/performance_bar/components/detailed_metric.vue
new file mode 100644
index 00000000000..145465f4ee9
--- /dev/null
+++ b/app/assets/javascripts/performance_bar/components/detailed_metric.vue
@@ -0,0 +1,78 @@
+<script>
+import GlModal from '~/vue_shared/components/gl_modal.vue';
+
+export default {
+  components: {
+    GlModal,
+  },
+  props: {
+    currentRequest: {
+      type: Object,
+      required: true,
+    },
+    metric: {
+      type: String,
+      required: true,
+    },
+    header: {
+      type: String,
+      required: true,
+    },
+    details: {
+      type: String,
+      required: true,
+    },
+    keys: {
+      type: Array,
+      required: true,
+    },
+  },
+};
+</script>
+<template>
+  <div
+    :id="`peek-view-${metric}`"
+    class="view"
+  >
+    <button
+      :data-target="`#modal-peek-${metric}-details`"
+      class="btn-blank btn-link bold"
+      type="button"
+      data-toggle="modal"
+    >
+      <span
+        v-if="currentRequest.details"
+        class="bold"
+      >
+        {{ currentRequest.details[metric].duration }}
+        /
+        {{ currentRequest.details[metric].calls }}
+      </span>
+    </button>
+    <gl-modal
+      v-if="currentRequest.details"
+      :id="`modal-peek-${metric}-details`"
+      :header-title-text="header"
+      class="performance-bar-modal"
+    >
+      <table class="table">
+        <tr
+          v-for="(item, index) in currentRequest.details[metric][details]"
+          :key="index"
+        >
+          <td><strong>{{ item.duration }}ms</strong></td>
+          <td
+            v-for="key in keys"
+            :key="key"
+          >
+            {{ item[key] }}
+          </td>
+        </tr>
+      </table>
+
+      <div slot="footer">
+      </div>
+    </gl-modal>
+    {{ metric }}
+  </div>
+</template>
diff --git a/app/assets/javascripts/performance_bar/components/performance_bar_app.vue b/app/assets/javascripts/performance_bar/components/performance_bar_app.vue
new file mode 100644
index 00000000000..88345cf2ad9
--- /dev/null
+++ b/app/assets/javascripts/performance_bar/components/performance_bar_app.vue
@@ -0,0 +1,191 @@
+<script>
+import $ from 'jquery';
+
+import PerformanceBarService from '../services/performance_bar_service';
+import detailedMetric from './detailed_metric.vue';
+import requestSelector from './request_selector.vue';
+import simpleMetric from './simple_metric.vue';
+import upstreamPerformanceBar from './upstream_performance_bar.vue';
+
+import Flash from '../../flash';
+
+export default {
+  components: {
+    detailedMetric,
+    requestSelector,
+    simpleMetric,
+    upstreamPerformanceBar,
+  },
+  props: {
+    store: {
+      type: Object,
+      required: true,
+    },
+    env: {
+      type: String,
+      required: true,
+    },
+    requestId: {
+      type: String,
+      required: true,
+    },
+    peekUrl: {
+      type: String,
+      required: true,
+    },
+    profileUrl: {
+      type: String,
+      required: true,
+    },
+  },
+  detailedMetrics: [
+    { metric: 'pg', header: 'SQL queries', details: 'queries', keys: ['sql'] },
+    {
+      metric: 'gitaly',
+      header: 'Gitaly calls',
+      details: 'details',
+      keys: ['feature', 'request'],
+    },
+  ],
+  simpleMetrics: ['redis', 'sidekiq'],
+  data() {
+    return { currentRequestId: '' };
+  },
+  computed: {
+    requests() {
+      return this.store.requestsWithDetails();
+    },
+    currentRequest: {
+      get() {
+        return this.store.findRequest(this.currentRequestId);
+      },
+      set(requestId) {
+        this.currentRequestId = requestId;
+      },
+    },
+    initialRequest() {
+      return this.currentRequestId === this.requestId;
+    },
+    lineProfileModal() {
+      return $('#modal-peek-line-profile');
+    },
+  },
+  mounted() {
+    this.interceptor = PerformanceBarService.registerInterceptor(
+      this.peekUrl,
+      this.loadRequestDetails,
+    );
+
+    this.loadRequestDetails(this.requestId, window.location.href);
+    this.currentRequest = this.requestId;
+
+    if (this.lineProfileModal.length) {
+      this.lineProfileModal.modal('toggle');
+    }
+  },
+  beforeDestroy() {
+    PerformanceBarService.removeInterceptor(this.interceptor);
+  },
+  methods: {
+    loadRequestDetails(requestId, requestUrl) {
+      if (!this.store.canTrackRequest(requestUrl)) {
+        return;
+      }
+
+      this.store.addRequest(requestId, requestUrl);
+
+      PerformanceBarService.fetchRequestDetails(this.peekUrl, requestId)
+        .then(res => {
+          this.store.addRequestDetails(requestId, res.data.data);
+        })
+        .catch(() =>
+          Flash(`Error getting performance bar results for ${requestId}`),
+        );
+    },
+    changeCurrentRequest(newRequestId) {
+      this.currentRequest = newRequestId;
+    },
+  },
+};
+</script>
+<template>
+  <div
+    id="js-peek"
+    :class="env"
+  >
+    <request-selector
+      v-if="currentRequest"
+      :current-request="currentRequest"
+      :requests="requests"
+      @change-current-request="changeCurrentRequest"
+    />
+    <div
+      id="peek-view-host"
+      class="view prepend-left-5"
+    >
+      <span
+        v-if="currentRequest && currentRequest.details"
+        class="current-host"
+      >
+        {{ currentRequest.details.host.hostname }}
+      </span>
+    </div>
+    <div
+      v-if="currentRequest"
+      class="wrapper"
+    >
+      <upstream-performance-bar
+        v-if="initialRequest && currentRequest.details"
+      />
+      <detailed-metric
+        v-for="metric in $options.detailedMetrics"
+        :key="metric.metric"
+        :current-request="currentRequest"
+        :metric="metric.metric"
+        :header="metric.header"
+        :details="metric.details"
+        :keys="metric.keys"
+      />
+      <div
+        v-if="initialRequest"
+        id="peek-view-rblineprof"
+        class="view"
+      >
+        <button
+          v-if="lineProfileModal.length"
+          class="btn-link btn-blank"
+          data-toggle="modal"
+          data-target="#modal-peek-line-profile"
+        >
+          profile
+        </button>
+        <a
+          v-else
+          :href="profileUrl"
+        >
+          profile
+        </a>
+      </div>
+      <simple-metric
+        v-for="metric in $options.simpleMetrics"
+        :current-request="currentRequest"
+        :key="metric"
+        :metric="metric"
+      />
+      <div
+        id="peek-view-gc"
+        class="view"
+      >
+        <span
+          v-if="currentRequest.details"
+          class="bold"
+        >
+          <span title="Invoke Time">{{ currentRequest.details.gc.gc_time }}</span>ms
+          /
+          <span title="Invoke Count">{{ currentRequest.details.gc.invokes }}</span>
+          gc
+        </span>
+      </div>
+    </div>
+  </div>
+</template>
diff --git a/app/assets/javascripts/performance_bar/components/request_selector.vue b/app/assets/javascripts/performance_bar/components/request_selector.vue
new file mode 100644
index 00000000000..2f360ea6f6c
--- /dev/null
+++ b/app/assets/javascripts/performance_bar/components/request_selector.vue
@@ -0,0 +1,52 @@
+<script>
+export default {
+  props: {
+    currentRequest: {
+      type: Object,
+      required: true,
+    },
+    requests: {
+      type: Array,
+      required: true,
+    },
+  },
+  data() {
+    return {
+      currentRequestId: this.currentRequest.id,
+    };
+  },
+  watch: {
+    currentRequestId(newRequestId) {
+      this.$emit('change-current-request', newRequestId);
+    },
+  },
+  methods: {
+    truncatedUrl(requestUrl) {
+      const components = requestUrl.replace(/\/$/, '').split('/');
+      let truncated = components[components.length - 1];
+
+      if (truncated.match(/^\d+$/)) {
+        truncated = `${components[components.length - 2]}/${truncated}`;
+      }
+
+      return truncated;
+    },
+  },
+};
+</script>
+<template>
+  <div
+    id="peek-request-selector"
+    class="append-right-5 pull-right"
+  >
+    <select v-model="currentRequestId">
+      <option
+        v-for="request in requests"
+        :key="request.id"
+        :value="request.id"
+      >
+        {{ truncatedUrl(request.url) }}
+      </option>
+    </select>
+  </div>
+</template>
diff --git a/app/assets/javascripts/performance_bar/components/simple_metric.vue b/app/assets/javascripts/performance_bar/components/simple_metric.vue
new file mode 100644
index 00000000000..b654bc66249
--- /dev/null
+++ b/app/assets/javascripts/performance_bar/components/simple_metric.vue
@@ -0,0 +1,30 @@
+<script>
+export default {
+  props: {
+    currentRequest: {
+      type: Object,
+      required: true,
+    },
+    metric: {
+      type: String,
+      required: true,
+    },
+  },
+};
+</script>
+<template>
+  <div
+    :id="`peek-view-${metric}`"
+    class="view"
+  >
+    <span
+      v-if="currentRequest.details"
+      class="bold"
+    >
+      {{ currentRequest.details[metric].duration }}
+      /
+      {{ currentRequest.details[metric].calls }}
+    </span>
+    {{ metric }}
+  </div>
+</template>
diff --git a/app/assets/javascripts/performance_bar/components/upstream_performance_bar.vue b/app/assets/javascripts/performance_bar/components/upstream_performance_bar.vue
new file mode 100644
index 00000000000..d438b1ec27b
--- /dev/null
+++ b/app/assets/javascripts/performance_bar/components/upstream_performance_bar.vue
@@ -0,0 +1,18 @@
+<script>
+export default {
+  mounted() {
+    const upstreamPerformanceBar = document
+      .getElementById('peek-view-performance-bar')
+      .cloneNode(true);
+
+    this.$refs.wrapper.appendChild(upstreamPerformanceBar);
+  },
+};
+</script>
+<template>
+  <div
+    id="peek-view-performance-bar-vue"
+    class="view"
+    ref="wrapper"
+  ></div>
+</template>
diff --git a/app/assets/javascripts/performance_bar/index.js b/app/assets/javascripts/performance_bar/index.js
new file mode 100644
index 00000000000..fca488120f6
--- /dev/null
+++ b/app/assets/javascripts/performance_bar/index.js
@@ -0,0 +1,37 @@
+import 'vendor/peek.performance_bar';
+
+import Vue from 'vue';
+import performanceBarApp from './components/performance_bar_app.vue';
+import PerformanceBarStore from './stores/performance_bar_store';
+
+export default () =>
+  new Vue({
+    el: '#js-peek',
+    components: {
+      performanceBarApp,
+    },
+    data() {
+      const performanceBarData = document.querySelector(this.$options.el)
+        .dataset;
+      const store = new PerformanceBarStore();
+
+      return {
+        store,
+        env: performanceBarData.env,
+        requestId: performanceBarData.requestId,
+        peekUrl: performanceBarData.peekUrl,
+        profileUrl: performanceBarData.profileUrl,
+      };
+    },
+    render(createElement) {
+      return createElement('performance-bar-app', {
+        props: {
+          store: this.store,
+          env: this.env,
+          requestId: this.requestId,
+          peekUrl: this.peekUrl,
+          profileUrl: this.profileUrl,
+        },
+      });
+    },
+  });
diff --git a/app/assets/javascripts/performance_bar/services/performance_bar_service.js b/app/assets/javascripts/performance_bar/services/performance_bar_service.js
new file mode 100644
index 00000000000..d8e792446c3
--- /dev/null
+++ b/app/assets/javascripts/performance_bar/services/performance_bar_service.js
@@ -0,0 +1,24 @@
+import axios from '../../lib/utils/axios_utils';
+
+export default class PerformanceBarService {
+  static fetchRequestDetails(peekUrl, requestId) {
+    return axios.get(peekUrl, { params: { request_id: requestId } });
+  }
+
+  static registerInterceptor(peekUrl, callback) {
+    return axios.interceptors.response.use(response => {
+      const requestId = response.headers['x-request-id'];
+      const requestUrl = response.config.url;
+
+      if (requestUrl !== peekUrl && requestId) {
+        callback(requestId, requestUrl);
+      }
+
+      return response;
+    });
+  }
+
+  static removeInterceptor(interceptor) {
+    axios.interceptors.response.eject(interceptor);
+  }
+}
diff --git a/app/assets/javascripts/performance_bar/stores/performance_bar_store.js b/app/assets/javascripts/performance_bar/stores/performance_bar_store.js
new file mode 100644
index 00000000000..c6b2f55243c
--- /dev/null
+++ b/app/assets/javascripts/performance_bar/stores/performance_bar_store.js
@@ -0,0 +1,39 @@
+export default class PerformanceBarStore {
+  constructor() {
+    this.requests = [];
+  }
+
+  addRequest(requestId, requestUrl, requestDetails) {
+    if (!this.findRequest(requestId)) {
+      this.requests.push({
+        id: requestId,
+        url: requestUrl,
+        details: requestDetails,
+      });
+    }
+
+    return this.requests;
+  }
+
+  findRequest(requestId) {
+    return this.requests.find(request => request.id === requestId);
+  }
+
+  addRequestDetails(requestId, requestDetails) {
+    const request = this.findRequest(requestId);
+
+    request.details = requestDetails;
+
+    return request;
+  }
+
+  requestsWithDetails() {
+    return this.requests.filter(request => request.details);
+  }
+
+  canTrackRequest(requestUrl) {
+    return (
+      this.requests.filter(request => request.url === requestUrl).length < 2
+    );
+  }
+}
diff --git a/app/assets/stylesheets/performance_bar.scss b/app/assets/stylesheets/performance_bar.scss
index 6e539e39ca1..d06148a7bf8 100644
--- a/app/assets/stylesheets/performance_bar.scss
+++ b/app/assets/stylesheets/performance_bar.scss
@@ -1,8 +1,8 @@
-@import "framework/variables";
-@import "peek/views/performance_bar";
-@import "peek/views/rblineprof";
+@import 'framework/variables';
+@import 'peek/views/performance_bar';
+@import 'peek/views/rblineprof';
 
-#peek {
+#js-peek {
   position: fixed;
   left: 0;
   top: 0;
@@ -21,14 +21,26 @@
 
   &.production {
     background-color: $perf-bar-production;
+
+    select {
+      background: $perf-bar-production;
+    }
   }
 
   &.staging {
     background-color: $perf-bar-staging;
+
+    select {
+      background: $perf-bar-staging;
+    }
   }
 
   &.development {
     background-color: $perf-bar-development;
+
+    select {
+      background: $perf-bar-development;
+    }
   }
 
   .wrapper {
@@ -42,11 +54,12 @@
     background: $perf-bar-bucket-bg;
     display: inline-block;
     padding: 4px 6px;
-    font-family: Consolas, "Liberation Mono", Courier, monospace;
+    font-family: Consolas, 'Liberation Mono', Courier, monospace;
     line-height: 1;
     color: $perf-bar-bucket-color;
     border-radius: 3px;
-    box-shadow: 0 1px 0 $perf-bar-bucket-box-shadow-from, inset 0 1px 2px $perf-bar-bucket-box-shadow-to;
+    box-shadow: 0 1px 0 $perf-bar-bucket-box-shadow-from,
+      inset 0 1px 2px $perf-bar-bucket-box-shadow-to;
 
     .hidden {
       display: none;
@@ -94,6 +107,10 @@
       max-width: 10000px !important;
     }
   }
+
+  .performance-bar-modal .modal-footer {
+    display: none;
+  }
 }
 
 #modal-peek-pg-queries-content {