test: lint the driver in a single evergreen task

This change speeds up evergreen runs by only linting the project
once per build. The linting variant will also show up separately
on PR builds, giving better signal about whether that is the cause
of build failures

Author: mbroadst

.evergreen/config.yml

@@ -112,6 +112,14 @@ functions:
 
           AUTH=${AUTH} SSL=${SSL} UNIFIED=${UNIFIED} MONGODB_URI="${MONGODB_URI}" bash
           ${PROJECT_DIRECTORY}/.evergreen/run-tests.sh
+  run checks:
+    - command: shell.exec
+      type: test
+      params:
+        working_dir: src
+        script: |
+          ${PREPARE_SHELL}
+          bash ${PROJECT_DIRECTORY}/.evergreen/run-checks.sh
   cleanup:
     - command: shell.exec
       params:
@@ -744,14 +752,20 @@ tasks:
     commands:
       - func: install dependencies
       - func: run atlas tests
+  - name: run-checks
+    tags:
+      - run-checks
+    commands:
+      - func: install dependencies
         vars:
-          VERSION: latest
+          NODE_LTS_NAME: erbium
+      - func: run checks
 buildvariants:
-  - name: macos-1014-dubnium
-    display_name: macOS 10.14 Node Dubnium
+  - name: macos-1014-erbium
+    display_name: macOS 10.14 Node Erbium
     run_on: macos-1014
     expansions:
-      NODE_LTS_NAME: dubnium
+      NODE_LTS_NAME: erbium
     tasks: &ref_0
       - test-latest-server
       - test-latest-replica_set
@@ -802,6 +816,12 @@ buildvariants:
       - test-2.6-replica_set-unified
       - test-2.6-sharded_cluster-unified
       - test-atlas-connectivity
+  - name: macos-1014-dubnium
+    display_name: macOS 10.14 Node Dubnium
+    run_on: macos-1014
+    expansions:
+      NODE_LTS_NAME: dubnium
+    tasks: *ref_0
   - name: macos-1014-carbon
     display_name: macOS 10.14 Node Carbon
     run_on: macos-1014
@@ -820,6 +840,12 @@ buildvariants:
     expansions:
       NODE_LTS_NAME: argon
     tasks: *ref_0
+  - name: rhel70-erbium
+    display_name: RHEL 7.0 Node Erbium
+    run_on: rhel70-small
+    expansions:
+      NODE_LTS_NAME: erbium
+    tasks: *ref_0
   - name: rhel70-dubnium
     display_name: RHEL 7.0 Node Dubnium
     run_on: rhel70-small
@@ -844,11 +870,11 @@ buildvariants:
     expansions:
       NODE_LTS_NAME: argon
     tasks: *ref_0
-  - name: ubuntu-14.04-dubnium
-    display_name: Ubuntu 14.04 Node Dubnium
+  - name: ubuntu-14.04-erbium
+    display_name: Ubuntu 14.04 Node Erbium
     run_on: ubuntu1404-test
     expansions:
-      NODE_LTS_NAME: dubnium
+      NODE_LTS_NAME: erbium
     tasks: &ref_1
       - test-4.0-server
       - test-4.0-replica_set
@@ -886,6 +912,13 @@ buildvariants:
       - test-2.6-server-unified
       - test-2.6-replica_set-unified
       - test-2.6-sharded_cluster-unified
+      - test-atlas-connectivity
+  - name: ubuntu-14.04-dubnium
+    display_name: Ubuntu 14.04 Node Dubnium
+    run_on: ubuntu1404-test
+    expansions:
+      NODE_LTS_NAME: dubnium
+    tasks: *ref_1
   - name: ubuntu-14.04-carbon
     display_name: Ubuntu 14.04 Node Carbon
     run_on: ubuntu1404-test
@@ -904,11 +937,11 @@ buildvariants:
     expansions:
       NODE_LTS_NAME: argon
     tasks: *ref_1
-  - name: ubuntu-18.04-dubnium
-    display_name: Ubuntu 18.04 Node Dubnium
+  - name: ubuntu-18.04-erbium
+    display_name: Ubuntu 18.04 Node Erbium
     run_on: ubuntu1804-test
     expansions:
-      NODE_LTS_NAME: dubnium
+      NODE_LTS_NAME: erbium
       CLIENT_ENCRYPTION: true
     tasks: &ref_2
       - test-latest-server
@@ -948,6 +981,13 @@ buildvariants:
       - test-3.2-replica_set-unified
       - test-3.2-sharded_cluster-unified
       - test-atlas-connectivity
+  - name: ubuntu-18.04-dubnium
+    display_name: Ubuntu 18.04 Node Dubnium
+    run_on: ubuntu1804-test
+    expansions:
+      NODE_LTS_NAME: dubnium
+      CLIENT_ENCRYPTION: true
+    tasks: *ref_2
   - name: ubuntu-18.04-carbon
     display_name: Ubuntu 18.04 Node Carbon
     run_on: ubuntu1804-test
@@ -969,3 +1009,8 @@ buildvariants:
       NODE_LTS_NAME: argon
       CLIENT_ENCRYPTION: true
     tasks: *ref_2
+  - name: lint
+    display_name: lint
+    run_on: rhel70
+    tasks:
+      - run-checks

.evergreen/config.yml.in

@@ -130,6 +130,15 @@ functions:
 
           AUTH=${AUTH} SSL=${SSL} UNIFIED=${UNIFIED} MONGODB_URI="${MONGODB_URI}" bash ${PROJECT_DIRECTORY}/.evergreen/run-tests.sh
 
+  "run checks":
+    - command: shell.exec
+      type: test
+      params:
+        working_dir: "src"
+        script: |
+          ${PREPARE_SHELL}
+          bash ${PROJECT_DIRECTORY}/.evergreen/run-checks.sh
+
   "cleanup":
     - command: shell.exec
       params:

.evergreen/generate_evergreen_tasks.js

@@ -6,7 +6,7 @@ const yaml = require('js-yaml');
 
 const LATEST_EFFECTIVE_VERSION = '5.0';
 const MONGODB_VERSIONS = ['latest', '4.2', '4.0', '3.6', '3.4', '3.2', '3.0', '2.6'];
-const NODE_VERSIONS = ['dubnium', 'carbon', 'boron', 'argon'];
+const NODE_VERSIONS = ['erbium', 'dubnium', 'carbon', 'boron', 'argon'];
 const TOPOLOGIES = ['server', 'replica_set', 'sharded_cluster'].concat([
   'server-unified',
   'replica_set-unified',
@@ -37,7 +37,7 @@ const OPERATING_SYSTEMS = [
     run_on: 'ubuntu1804-test',
     mongoVersion: '>=3.2',
     clientEncryption: true
-  },
+  }
 
   // Windows. reenable this when nvm supports windows, or we settle on an alternative tool
   // {
@@ -67,6 +67,7 @@ const OPERATING_SYSTEMS = [
 );
 
 const TASKS = [];
+const SINGLETON_TASKS = [];
 
 function makeTask({ mongoVersion, topology }) {
   let topologyForTest = topology;
@@ -80,9 +81,7 @@ function makeTask({ mongoVersion, topology }) {
     name: `test-${mongoVersion}-${topology}`,
     tags: [mongoVersion, topology],
     commands: [
-      {
-        func: 'install dependencies'
-      },
+      { func: 'install dependencies' },
       {
         func: 'bootstrap mongo-orchestration',
         vars: {
@@ -101,20 +100,11 @@ MONGODB_VERSIONS.forEach(mongoVersion => {
   });
 });
 
+// singleton task for connectivity tests
 TASKS.push({
   name: 'test-atlas-connectivity',
   tags: ['atlas-connect'],
-  commands: [
-    {
-      func: 'install dependencies'
-    },
-    {
-      func: 'run atlas tests',
-      vars: {
-        VERSION: 'latest'
-      }
-    }
-  ]
+  commands: [{ func: 'install dependencies' }, { func: 'run atlas tests' }]
 });
 
 const BUILD_VARIANTS = [];
@@ -129,8 +119,12 @@ const getTaskList = (() => {
     }
 
     const ret = TASKS.filter(task => {
-      const { VERSION } = task.commands.filter(task => !!task.vars)[0].vars;
+      const tasksWithVars = task.commands.filter(task => !!task.vars);
+      if (!tasksWithVars.length) {
+        return true;
+      }
 
+      const { VERSION } = tasksWithVars[0].vars || {};
       if (VERSION === 'latest') {
         return semver.satisfies(semver.coerce(LATEST_EFFECTIVE_VERSION), mongoVersion);
       }
@@ -170,9 +164,30 @@ OPERATING_SYSTEMS.forEach(
   }
 );
 
-const fileData = yaml.safeLoad(fs.readFileSync(`${__dirname}/config.yml.in`, 'utf8'));
+// singleton build variant for linting
+SINGLETON_TASKS.push({
+  name: 'run-checks',
+  tags: ['run-checks'],
+  commands: [
+    {
+      func: 'install dependencies',
+      vars: {
+        NODE_LTS_NAME: 'erbium'
+      }
+    },
+    { func: 'run checks' }
+  ]
+});
 
-fileData.tasks = (fileData.tasks || []).concat(TASKS);
+BUILD_VARIANTS.push({
+  name: 'lint',
+  display_name: 'lint',
+  run_on: 'rhel70',
+  tasks: ['run-checks']
+});
+
+const fileData = yaml.safeLoad(fs.readFileSync(`${__dirname}/config.yml.in`, 'utf8'));
+fileData.tasks = (fileData.tasks || []).concat(TASKS).concat(SINGLETON_TASKS);
 fileData.buildvariants = (fileData.buildvariants || []).concat(BUILD_VARIANTS);
 
 fs.writeFileSync(`${__dirname}/config.yml`, yaml.safeDump(fileData, { lineWidth: 120 }), 'utf8');

.evergreen/run-checks.sh

@@ -0,0 +1,9 @@
+#!/bin/bash
+set -o errexit  # Exit the script with error if any of the commands fail
+
+export PROJECT_DIRECTORY="$(pwd)"
+NODE_ARTIFACTS_PATH="${PROJECT_DIRECTORY}/node-artifacts"
+export NVM_DIR="${NODE_ARTIFACTS_PATH}/nvm"
+[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
+
+npm run lint

.evergreen/run-tests.sh

@@ -30,4 +30,4 @@ else
   npm install mongodb-client-encryption
 fi
 
-MONGODB_UNIFIED_TOPOLOGY=${UNIFIED} MONGODB_URI=${MONGODB_URI} npm test
+MONGODB_UNIFIED_TOPOLOGY=${UNIFIED} MONGODB_URI=${MONGODB_URI} npm run test-nolint