Merge pull request #16 from nib-health-funds/dry-run

Implements dry run feature

Author: krutisfood

README.md

@@ -32,6 +32,15 @@ Hammertime is intended to be run in response to a Lambda scheduled event, e.g
 
 Note when constructing schedule events in AWS, that times are in UTC.
 
+### Enabling/Disabling
+
+You can enable/disable hammertime using the environment variable `HAMMERTIME_ENABLED` at the time of deployment. 'true' enables hammertime.
+
+### Dry run
+
+Hammertime has a dry-run feature for when you are not quite ready to unleash the [hammer pants](https://en.wikipedia.org/wiki/Hammer_pants) on your entire fleet of EC2s just yet.
+By setting `HAMMERTIME_DRY_RUN` to 'true', you enable dry-run in which hammertime does not touch your EC2s but will still log what it _would_ have touched.
+
 ## Deployment
 
 Refer to the [serverless framework](!https://serverless.com/) for detailed instructions, but should be as simple as

hammertime.js

@@ -1,7 +1,10 @@
 const start = require('./src/start');
 const stop = require('./src/stop');
 
+// Try and use env var, otherwise default to false.
+const dryRun = process.env.hammerTimeDryRun === 'true' || false;
+
 module.exports = {
-  start,
-  stop,
+  start: (event, context, callback) => start({ event, context, callback, dryRun }),
+  stop: (event, context, callback) => stop({ event, context, callback, dryRun }),
 };

isDryRun.js

@@ -0,0 +1 @@
+module.exports.isDryRun = () => process.env.HAMMERTIME_DRY_RUN === 'true';

isEnabled.js

@@ -0,0 +1 @@
+module.exports.isEnabled = () => process.env.HAMMERTIME_ENABLED === 'true';

schedule.js

@@ -26,6 +26,10 @@ provider:
         - "logs:CreateLogStream"
         - "logs:PutLogEvents"
       Resource: "arn:aws:logs:*:*:*"
+    environment:
+      hammerTimeDryRun: ${file(./isDryRun.js):isDryRun}
+  custom:
+    enabled: ${file(./isEnabled.js):isEnabled}
 
 functions:
   stop-hammertime:
@@ -34,12 +38,12 @@ functions:
     events:
       - schedule:
           rate: cron(30 9 * * ? *) # ADST 8:30PM, AEST 7:30PM every day
-          enabled: ${file(./schedule.js):enabled}
+          enabled: ${self:custom:enabled}
 
   start-hammertime:
     handler: hammertime.start
     timeout: 180
     events:
       - schedule:
           rate: cron(30 19 * * ? *) # ADST 6:30AM, AEST 5:30AM every day
-          enabled: ${file(./schedule.js):enabled}
+          enabled: ${self:custom:enabled}

serverless.yml

@@ -5,53 +5,67 @@ const startInstances = require('./instances/startInstances');
 const listInstancesToStart = require('./instances/listInstancesToStart');
 const untagInstances = require('./instances/untagInstances');
 
-function startAllInstances() {
+function startAllInstances(dryRun) {
   return listInstancesToStart()
     .then((startableInstances) => {
-      console.log(`Found the following ${startableInstances.length} instances to start up...`);
+      if (dryRun) {
+        console.log('Dry run is enabled, will not start or untag any instances.');
+        return [];
+      }
+
       if (startableInstances.length === 0) {
-        console.log('None! Moving on.');
-        return 'No instances to turn on';
+        console.log('No instances found to start, moving on...');
+        return [];
       }
 
+      console.log(`Found the following ${startableInstances.length} instances to start up...`);
       startableInstances.forEach((instance) => {
         console.log(instance);
       });
-      return startInstances(startableInstances);
-    })
-    .then((startedInstances) => {
-      console.log('Finished starting instances. Moving on to untag them.');
-      return untagInstances(startedInstances);
+
+      return startInstances(startableInstances).then((startedInstanceIds) => {
+        console.log('Finished starting instances. Moving on to untag them.');
+        return untagInstances(startedInstanceIds);
+      });
     });
 }
 
-function spinUpASGs() {
+function spinUpASGs(dryRun) {
   return listASGsToStart()
     .then((startableASGs) => {
-      console.log(`Found the following ${startableASGs.length} instances to start up...`);
+      if (dryRun) {
+        console.log('Dry run is enabled, will not start or untag any ASGs.');
+        return [];
+      }
+
       if (startableASGs.length === 0) {
-        console.log('None! Moving on.');
-        return 'No ASGs to spin up';
+        console.log('No ASGs found to spin up, moving on...');
+        return [];
       }
 
+      console.log(`Found the following ${startableASGs.length} instances to start up...`);
+      // Log startableASGs for easy debugging
       startableASGs.forEach((asg) => {
         console.log(asg.AutoScalingGroupName);
       });
-      return startASGs(startableASGs);
-    })
-    .then((startedASGs) => {
-      console.log(`Finished spinning up ASGs. Moving on to untag ${startedASGs.length} of them.`);
-      return untagASGs(startedASGs);
+
+      return startASGs(startableASGs).then((startedASGs) => {
+        console.log(`Finished spinning up ASGs. Moving on to untag ${startedASGs.length} of them.`);
+        return untagASGs(startedASGs);
+      });
     });
 }
 
-module.exports = function start(event, context, callback) {
+module.exports = function start(options) {
+  const { event, callback, dryRun } = options;
   console.log('Break it down!');
   Promise.all([
-    startAllInstances(),
-    spinUpASGs(),
+    startAllInstances(dryRun),
+    spinUpASGs(dryRun),
   ]).then(() => {
-    console.log('All instances and ASGs started successfully. Good morning!');
+    if (!dryRun) {
+      console.log('All instances and ASGs started successfully. Good morning!');
+    }
     callback(null, { message: 'Start: Hammertime successfully completed.' }, event);
   }).catch((err) => {
     console.error(err);

src/start.js

@@ -5,57 +5,74 @@ const listInstancesToStop = require('./instances/listInstancesToStop');
 const tagInstances = require('./instances/tagInstances');
 const stopInstances = require('./instances/stopInstances');
 
-function spinDownASGs() {
+function stopAllInstances(dryRun) {
+  return listInstancesToStop()
+    .then((stoppableInstances) => {
+      if (dryRun) {
+        console.log('Dry run is enabled, will not stop or tag any instances.');
+        return [];
+      }
+
+      if (stoppableInstances.length === 0) {
+        console.log('No instances found to stop, moving on...');
+        return [];
+      }
+
+      console.log('Found the following instances to shut down...');
+      stoppableInstances.forEach((instance) => {
+        console.log(instance);
+      });
+
+      return tagInstances(stoppableInstances).then((taggedInstances) => {
+        if (taggedInstances.length > 0) {
+          console.log('Finished tagging instances. Moving on to stop them.');
+          return stopInstances(taggedInstances);
+        }
+
+        return [];
+      });
+    });
+}
+
+function spinDownASGs(dryRun) {
   return listASGsToStop()
     .then((stoppableASGs) => {
-      console.log(`Found the following ${stoppableASGs.length} instances to spin down...`);
+      if (dryRun) {
+        console.log('Dry run is enabled, will not stop or tag any ASGs.');
+        return [];
+      }
+
       if (stoppableASGs.length === 0) {
-        console.log('None! Moving on.');
+        console.log('No ASGs to spin down, moving on...');
         return [];
       }
 
+      console.log(`Found the following ${stoppableASGs.length} instances to spin down...`);
       stoppableASGs.forEach((asg) => {
         console.log(asg.AutoScalingGroupName);
       });
-      return tagASGs(stoppableASGs);
-    })
-    .then((taggedASGs) => {
-      if (taggedASGs.length > 0) {
-        console.log(`Finished tagging ASGs. Moving on to spin down ${taggedASGs.length} of them.`);
-        return stopASGs(taggedASGs);
-      }
-    });
-}
 
-function stopAllInstances() {
-  return listInstancesToStop()
-    .then((stoppableInstances) => {
-      console.log('Found the following instances to shut down...');
-      if (stoppableInstances.length === 0) {
-        console.log('None! Moving on.');
-        return [];
-      }
+      return tagASGs(stoppableASGs).then((taggedASGs) => {
+        if (taggedASGs.length > 0) {
+          console.log(`Finished tagging ASGs. Moving on to spin down ${taggedASGs.length} of them.`);
+          return stopASGs(taggedASGs);
+        }
 
-      stoppableInstances.forEach((instance) => {
-        console.log(instance);
+        return [];
       });
-      return tagInstances(stoppableInstances);
-    })
-    .then((taggedInstances) => {
-      if (taggedInstances.length > 0) {
-        console.log('Finished tagging instances. Moving on to stop them.');
-        return stopInstances(taggedInstances);
-      }
     });
 }
 
-module.exports = function stop(event, context, callback) {
+module.exports = function stop(options) {
+  const { event, callback, dryRun } = options;
   console.log('Stop. Hammertime!');
   Promise.all([
-    stopAllInstances(),
-    spinDownASGs(),
+    stopAllInstances(dryRun),
+    spinDownASGs(dryRun),
   ]).then(() => {
-    console.log('All instances and ASGs stopped successfully. Good night!');
+    if (!dryRun) {
+      console.log('All instances and ASGs stopped successfully. Good night!');
+    }
     callback(null, { message: 'Stop: Hammertime successfully completed.' }, event);
   }).catch((err) => {
     console.error(err);