From 29e1b69f06d0cc221890c0416500cd2865fd785f Mon Sep 17 00:00:00 2001
From: Cameron Matheson <cameron@instructure.com>
Date: Mon, 26 Feb 2018 16:05:10 -0700
Subject: [PATCH] graphql: data dog instrumentation

closes RECNVS-325

Test plan:
  * do something to monitor statsd traffic (maybe
    `nc -kul 8125`?)
  * queries written in graphiql should not be instrumented
  * student context card queries should be logged

Change-Id: Ie86075b739df36e49b5f9ebcf320e50f8c140ecc
Reviewed-on: https://gerrit.instructure.com/141965
Tested-by: Jenkins
Reviewed-by: Jonathan Featherstone <jfeatherstone@instructure.com>
QA-Review: Collin Parrish <cparrish@instructure.com>
Product-Review: Cameron Matheson <cameron@instructure.com>
---
 Gemfile.d/app.rb                              |  1 +
 app/controllers/graphql_controller.rb         | 12 +++++++-
 app/graphql/tracers/datadog_tracer.rb         | 28 +++++++++++++++++++
 .../GraphQLStudentContextTray.js              |  1 +
 spec/controllers/graphql_controller_spec.rb   | 13 +++++++++
 5 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 app/graphql/tracers/datadog_tracer.rb

diff --git a/Gemfile.d/app.rb b/Gemfile.d/app.rb
index 5edfafca99b..9bcc05c8ca3 100644
--- a/Gemfile.d/app.rb
+++ b/Gemfile.d/app.rb
@@ -163,3 +163,4 @@ gem 'twitter', path: 'gems/twitter'
 gem 'vericite_api', '1.5.3'
 gem 'utf8_cleaner', path: 'gems/utf8_cleaner'
 gem 'workflow', path: 'gems/workflow'
+gem 'dogstatsd-ruby', '3.3.0'
diff --git a/app/controllers/graphql_controller.rb b/app/controllers/graphql_controller.rb
index f07f2aa1675..a70cfd42f1e 100644
--- a/app/controllers/graphql_controller.rb
+++ b/app/controllers/graphql_controller.rb
@@ -4,22 +4,32 @@ class GraphQLController < ApplicationController
   before_action :require_user, except: :execute
   before_action :require_graphql_feature_flag
 
+
   def execute
     query = params[:query]
     variables = params[:variables] || {}
+    tracers = if request.headers["GraphQL-Metrics"] == "true"
+                domain = request.host_with_port.sub(':', '_')
+                [Tracers::DatadogTracer.new(domain)]
+              else
+                []
+              end
     context = {
       current_user: @current_user,
       session: session,
       request: request,
+      tracers: tracers
     }
+    result = nil
 
     ActiveRecord::Base.transaction do
       timeout = Integer(Setting.get('graphql_statement_timeout', '60_000'))
       ActiveRecord::Base.connection.execute "SET statement_timeout = #{timeout}"
 
       result = CanvasSchema.execute(query, variables: variables, context: context)
-      render json: result
     end
+
+    render json: result
   end
 
   def graphiql
diff --git a/app/graphql/tracers/datadog_tracer.rb b/app/graphql/tracers/datadog_tracer.rb
new file mode 100644
index 00000000000..6a38b7d496c
--- /dev/null
+++ b/app/graphql/tracers/datadog_tracer.rb
@@ -0,0 +1,28 @@
+require 'datadog/statsd'
+
+module Tracers
+  class DatadogTracer
+    def initialize(domain)
+      @domain = domain
+      @statsd = Datadog::Statsd.new('localhost', 8125)
+    end
+
+    def trace(key, metadata)
+      if key == "execute_query"
+        @statsd.batch do |statsd|
+          query_name = metadata[:query].operation_name || "unnamed"
+          tags = [
+            "query_md5:#{Digest::MD5.hexdigest(metadata[:query].query_string)}",
+            "domain:#@domain",
+          ]
+          statsd.increment("graphql.#{query_name}.count", tags: tags)
+          statsd.time("graphql.#{query_name}.time", tags: tags) do
+            yield
+          end
+        end
+      else
+        yield
+      end
+    end
+  end
+end
diff --git a/app/jsx/context_cards/GraphQLStudentContextTray.js b/app/jsx/context_cards/GraphQLStudentContextTray.js
index 349805fc2dc..949a661ddad 100644
--- a/app/jsx/context_cards/GraphQLStudentContextTray.js
+++ b/app/jsx/context_cards/GraphQLStudentContextTray.js
@@ -10,6 +10,7 @@ const client = new ApolloClient({
     opts: {
       headers: {
         'X-Requested-With': 'XMLHttpRequest',
+        'GraphQL-Metrics': true,
         'X-CSRF-Token': $.cookie('_csrf_token') // TODO: probably need to move this io a middleware (http://dev.apollodata.com/core/network.html)
       },
       credentials: 'same-origin'
diff --git a/spec/controllers/graphql_controller_spec.rb b/spec/controllers/graphql_controller_spec.rb
index dc577e5057e..541ba4bd351 100644
--- a/spec/controllers/graphql_controller_spec.rb
+++ b/spec/controllers/graphql_controller_spec.rb
@@ -62,5 +62,18 @@ describe GraphQLController do
       post :execute, params: {query: "{}"}
       expect(JSON.parse(response.body)["errors"]).not_to be_blank
     end
+
+    context "data dog metrics" do
+      it "reports data dog metrics if requested" do
+        expect_any_instance_of(Tracers::DatadogTracer).to receive :trace
+        request.headers["GraphQL-Metrics"] = "true"
+        post :execute, params: {query: '{legacyNode(User, 1) { id }'}
+      end
+
+      it "doesn't report normally" do
+        expect_any_instance_of(Tracers::DatadogTracer).not_to receive :trace
+        post :execute, params: {query: '{legacyNode(User, 1) { id }'}
+      end
+    end
   end
 end