Initial commit

Author: Szpadel

.clang-format

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+Language:        JavaScript
+BasedOnStyle:    Google
+ColumnLimit:     80
+IndentWidth:     4

.gitignore

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+/node_modules
+/dist

.travis.yml

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+os: linux
+language: generic
+
+services:
+  - docker
+
+script:
+  - ./build.sh
+
+deploy:
+  - provider: releases
+    token: $GITHUB_OAUTH_TOKEN
+    file_glob: true
+    file: "dist/lambda.zip"
+    skip_cleanup: true
+    cleanup: false
+    on:
+      tags: true

build.sh

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+#!/usr/bin/env bash
+set -e
+
+if command -v podman;then
+    DOCKER=podman
+elif command -v docker;then
+    DOCKER=docker
+else
+    echo "Could not locate any docker runtime"
+    exit 1
+fi
+
+IMAGE=local/mageops-node-coordinator-build
+
+"$DOCKER" build -t "$IMAGE" ./build
+"$DOCKER" run --rm -v "$PWD:/workdir:z" "$IMAGE"

build/Dockerfile

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+FROM node:12-alpine
+
+RUN apk add --no-cache zip
+
+VOLUME /workdir
+WORKDIR /workdir
+
+ENTRYPOINT set -ex && yarn install \
+    && rm -rf dist \
+    && yarn build \
+    && rm -rf node_modules \
+    && yarn install --prod \
+    && mv node_modules dist/node_modules \
+    && (cd dist && zip -r9 /tmp/lambda-$$.zip *) \
+    && rm dist -rf \
+    && mkdir -p dist \
+    && mv /tmp/lambda-$$.zip dist/lambda.zip

package.json

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+{
+  "name": "mageops-node-coordinator",
+  "version": "1.0.0",
+  "main": "index.js",
+  "license": "MIT",
+  "private": true,
+  "scripts": {
+    "build": "tsc"
+  },
+  "devDependencies": {
+    "@types/node": "^13.13.1",
+    "typescript": "^3.8.3"
+  },
+  "dependencies": {
+    "aws-sdk": "^2.659.0"
+  }
+}

src/ec2-facade.ts

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+import {EC2} from 'aws-sdk';
+
+export class EC2Facade {
+    protected ec2 = new EC2();
+
+
+    describeInstances(req: EC2.DescribeInstancesRequest):
+        Promise<EC2.DescribeInstancesResult> {
+        return new Promise(
+            (resolve, reject) =>
+                this.ec2.describeInstances(req, (err, data) => {
+                    if (!!err) {
+                        reject(err);
+                    } else {
+                        resolve(data);
+                    }
+                }));
+    }
+
+    createTags(req: EC2.CreateTagsRequest): Promise<{}> {
+        return new Promise(
+            (resolve, reject) => this.ec2.createTags(req, (err, data) => {
+                if (!!err) {
+                    reject(err);
+                } else {
+                    resolve(data);
+                }
+            }));
+    }
+
+    deleteTags(req: EC2.DeleteTagsRequest): Promise<{}> {
+        return new Promise(
+            (resolve, reject) => this.ec2.deleteTags(req, (err, data) => {
+                if (!!err) {
+                    reject(err);
+                } else {
+                    resolve(data);
+                }
+            }));
+    }
+
+    createInstanceTags(instance: EC2.Instance, tags: EC2.TagList): Promise<{}> {
+        const id = instance.InstanceId;
+        if (!id) {
+            throw Error('InstanceId is missing');
+        }
+        return this.createTags({
+            Resources: [id],
+            Tags: tags,
+        });
+    }
+
+    deleteInstanceTags(instance: EC2.Instance, tags: EC2.TagList): Promise<{}> {
+        const id = instance.InstanceId;
+        if (!id) {
+            throw Error('InstanceId is missing');
+        }
+        return this.deleteTags({
+            Resources: [id],
+            Tags: tags,
+        });
+    }
+}

src/index.ts

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+import {EC2} from 'aws-sdk';
+import {exactTag, except, flatten, instanceAge, namedTag} from 'utils';
+
+import {EC2Facade} from './ec2-facade';
+
+const cronTagName = 'Cron';
+const cronTagValue = 'Present';
+
+class CreateTags {
+    private project: string;
+    private environment: string;
+    private globalFilter: EC2.FilterList = [
+        {Name: 'tag:Infrastructure', Values: ['mageops']},
+    ];
+
+    private projectFilter: EC2.FilterList;
+
+    private appNodeFilter: EC2.FilterList = [
+        {Name: 'tag:Role', Values: ['app']},
+        {Name: 'instance-state-name', Values: ['running']},
+    ];
+
+    private ec2 = new EC2Facade();
+
+    constructor() {
+        const project = process.env['PROJECT'];
+        if (!project) {
+            throw Error('PROJECT not specified');
+        }
+        this.project = project;
+
+        const environment = process.env['ENVIRONMENT'];
+        if (!environment) {
+            throw Error('ENVIRONMENT not specified');
+        }
+        this.environment = environment;
+        console.log(
+            `Using project: ${this.project}, environment: ${this.environment}`);
+
+        this.projectFilter = [
+            {Name: 'tag:Project', Values: [this.project]},
+            {Name: 'tag:Environment', Values: [this.environment]},
+        ];
+    }
+
+    async tagCron() {
+        const reservations = await this.ec2.describeInstances({
+            Filters: [
+                ...this.globalFilter,
+                ...this.projectFilter,
+                ...this.appNodeFilter,
+            ],
+        });
+
+        const instances =
+            (reservations.Reservations ?? []).map(r => r.Instances)
+            .filter((i): i is EC2.InstanceList => !!i)
+            .reduce(flatten, [])
+            .sort(instanceAge);
+
+        const [oldest, ...rest] = instances;
+
+        if (!oldest) {
+            console.log(`There is no instances found!`);
+            return;
+        }
+
+        const updates = [];
+
+        if(!oldest.Tags?.find(exactTag(cronTagName, cronTagValue))) {
+            updates.push(this.ec2.createInstanceTags(oldest, [
+                {Key: cronTagName, Value: cronTagValue},
+            ]));
+        }
+
+        for (const instance of rest) {
+            if(instance.Tags?.find(exactTag(cronTagName, cronTagValue))) {
+                updates.push(
+                    this.ec2.deleteInstanceTags(
+                        instance, instance.Tags.filter(namedTag(cronTagName))),
+                );
+            }
+        }
+
+        await Promise.all(updates);
+    }
+}
+
+export async function handler() {
+    const tagger = new CreateTags();
+    await tagger.tagCron();
+
+    return {
+        statusCode: 200,
+        body: 'OK',
+    };
+}

src/utils.ts

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+import {EC2} from 'aws-sdk';
+
+export function flatten<T>(acc: T[], item: T[]): T[] {
+    return [...acc, ...item];
+}
+
+export function instanceAge(a: EC2.Instance, b: EC2.Instance): number {
+    // ?? is not formatted correctly
+    // clang-format off
+    const aTime = a.LaunchTime ?.getTime() ?? Infinity;
+    const bTime = b.LaunchTime ?.getTime() ?? Infinity;
+    // clang-format on
+    return aTime - bTime;
+}
+
+export function exactTag(name: string, value: string): (tag: EC2.Tag) =>
+    boolean {
+    return (tag) => tag.Key === name && tag.Value === value;
+}
+
+export function namedTag(name: string): (tag: EC2.Tag) => boolean {
+    return (tag) => tag.Key === name;
+}
+
+export function except<T>(fn: (i: T) => boolean): (i: T) => boolean {
+    return (i) => !fn(i);
+}

tsconfig.json

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+{
+  "compilerOptions": {
+    "target": "ES2019",
+    "module": "commonjs",
+    "strict": true,
+    "noFallthroughCasesInSwitch": true,
+    "strictBindCallApply": true,
+    "noImplicitReturns": true,
+    "experimentalDecorators": true,
+    "downlevelIteration": true,
+    "moduleResolution": "node",
+    "esModuleInterop": true,
+    "forceConsistentCasingInFileNames": true,
+    "outDir": "./dist",
+    "sourceRoot": "./src",
+    "declaration": true,
+    "sourceMap": true,
+    "baseUrl": "./src",
+  }
+}