feat: base opentelemetry integration

index.js

@@ -38,6 +38,7 @@ const {
   MER_ERR_METHOD_NOT_ALLOWED,
   MER_ERR_INVALID_METHOD
 } = require('./lib/errors')
+const tracer = require('./lib/tracer')
 
 const kLoaders = Symbol('mercurius.loaders')
 const kFactory = Symbol('mercurius.loadersFactory')
@@ -382,12 +383,18 @@ const plugin = fp(async function (app, opts) {
   }
 
   async function fastifyGraphQl (source, context, variables, operationName) {
+    const span = tracer.startSpan('mercurius - graphql', { parent: tracer.getCurrentSpan() })
+
     context = Object.assign({ app: this, lruGatewayResolvers }, context)
     const reply = context.reply
 
     // Parse, with a little lru
     const cached = lru !== null && lru.get(source)
     let document = null
+
+    // Add opentelemetry attributes
+    span.setAttribute('mercurius.cached', !!cached)
+
     if (!cached) {
       // We use two caches to avoid errors bust the good
       // cache. This is a protection against DoS attacks
@@ -397,6 +404,7 @@ const plugin = fp(async function (app, opts) {
         // this query errored
         const err = new MER_ERR_GQL_VALIDATION()
         err.errors = cachedError.validationErrors
+        span.end()
         throw err
       }
 
@@ -405,6 +413,7 @@ const plugin = fp(async function (app, opts) {
       } catch (syntaxError) {
         const err = new MER_ERR_GQL_VALIDATION()
         err.errors = [syntaxError]
+        span.end()
         throw err
       }
 
@@ -425,6 +434,7 @@ const plugin = fp(async function (app, opts) {
         }
         const err = new MER_ERR_GQL_VALIDATION()
         err.errors = validationErrors
+        span.end()
         throw err
       }
 
@@ -434,6 +444,7 @@ const plugin = fp(async function (app, opts) {
         if (queryDepthErrors.length > 0) {
           const err = new MER_ERR_GQL_VALIDATION()
           err.errors = queryDepthErrors
+          span.end()
           throw err
         }
       }
@@ -451,6 +462,7 @@ const plugin = fp(async function (app, opts) {
       if (operationAST.operation !== 'query') {
         const err = new MER_ERR_METHOD_NOT_ALLOWED()
         err.errors = [new Error('Operation cannot be performed via a GET request')]
+        span.end()
         throw err
       }
     }
@@ -463,7 +475,9 @@ const plugin = fp(async function (app, opts) {
     if (cached && cached.jit !== null) {
       const execution = await cached.jit.query(root, context, variables || {})
 
-      return maybeFormatErrors(execution, context)
+      const resWithFormatedErrors = maybeFormatErrors(execution, context)
+      span.end()
+      return resWithFormatedErrors
     }
 
     // Validate variables
@@ -472,6 +486,7 @@ const plugin = fp(async function (app, opts) {
       if (Array.isArray(executionContext)) {
         const err = new MER_ERR_GQL_VALIDATION()
         err.errors = executionContext
+        span.end()
         throw err
       }
     }
@@ -485,7 +500,9 @@ const plugin = fp(async function (app, opts) {
       operationName
     )
 
-    return maybeFormatErrors(execution, context)
+    const resWithFormatedErrors = maybeFormatErrors(execution, context)
+    span.end()
+    return resWithFormatedErrors
   }
 
   function maybeFormatErrors (execution, context) {

lib/tracer.js

@@ -0,0 +1,5 @@
+'use strict'
+const api = require('@opentelemetry/api')
+const meta = require('../package.json')
+
+module.exports = api.trace.getTracer(meta.name, meta.version)

package.json

@@ -28,6 +28,7 @@
     "@graphql-tools/merge": "^6.2.4",
     "@graphql-tools/schema": "^6.2.4",
     "@graphql-tools/utils": "^6.2.4",
+    "@opentelemetry/api": "^0.13.0",
     "@sinonjs/fake-timers": "^6.0.1",
     "@types/node": "^14.0.23",
     "@types/ws": "^7.2.6",

test/opentelemetry.js

@@ -0,0 +1,75 @@
+'use strict'
+const { test } = require('tap')
+const Fastify = require('fastify')
+const api = require('@opentelemetry/api')
+const GQL = require('..')
+
+test('Should add opentelemetry span and cached attribute', async (t) => {
+  t.plan(6)
+
+  const testSpanContext = {
+    traceId: 'd4cda95b652f4a1592b449d5929fda1b',
+    spanId: '6e0c63257de34c92',
+    traceFlags: api.TraceFlags.NONE
+  }
+  class TestSpan extends api.NoopSpan {
+    setAttribute (name, value) {
+      t.is(name, 'mercurius.cached')
+      t.is(value, false)
+    }
+
+    end () {
+      t.pass()
+    }
+  }
+  const dummySpan = new TestSpan(testSpanContext)
+  class TestTracer extends api.NoopTracer {
+    startSpan (name, opts) {
+      t.is(name, 'mercurius - graphql')
+      t.deepEquals(opts.parent.context(), dummySpan.context())
+      return new TestSpan()
+    }
+
+    getCurrentSpan () {
+      return dummySpan
+    }
+  }
+  class TestTracerProvider extends api.NoopTracerProvider {
+    getTracer () {
+      return new TestTracer()
+    }
+  }
+  api.trace.setGlobalTracerProvider(new TestTracerProvider())
+
+  const app = Fastify()
+  const schema = `
+    type Query {
+      add(x: Int, y: Int): Int
+    }
+  `
+
+  const resolvers = {
+    add: async ({ x, y }) => x + y
+  }
+
+  app.register(GQL, {
+    schema,
+    resolvers
+  })
+
+  app.get('/', async function (req, reply) {
+    const query = '{ add(x: 2, y: 2) }'
+    return reply.graphql(query)
+  })
+
+  const res = await app.inject({
+    method: 'GET',
+    url: '/'
+  })
+
+  t.deepEqual(JSON.parse(res.body), {
+    data: {
+      add: 4
+    }
+  })
+})