Merge pull request #269 from guardian/aa-asg-auto-userdata

feat: auto generating UserData

src/constructs/autoscaling/asg.test.ts

@@ -19,7 +19,9 @@ describe("The GuAutoScalingGroup", () => {
     publicSubnetIds: [""],
   });
 
-  const { userData } = new GuUserData().addCommands(...["service some-dependency start", "service my-app start"]);
+  const { userData } = new GuUserData(simpleGuStackForTesting()).addCommands(
+    ...["service some-dependency start", "service my-app start"]
+  );
 
   const defaultProps: GuAutoScalingGroupProps = {
     vpc,

src/constructs/autoscaling/user-data.test.ts

@@ -0,0 +1,117 @@
+import "@aws-cdk/assert/jest";
+import { Vpc } from "@aws-cdk/aws-ec2";
+import { Stack } from "@aws-cdk/core";
+import { simpleGuStackForTesting } from "../../../test/utils";
+import { Stage } from "../../constants";
+import { GuDistributionBucketParameter } from "../core";
+import { GuAutoScalingGroup } from "./asg";
+import type { GuUserDataProps } from "./user-data";
+import { GuUserData } from "./user-data";
+
+describe("GuUserData", () => {
+  const vpc = Vpc.fromVpcAttributes(new Stack(), "VPC", {
+    vpcId: "test",
+    availabilityZones: [""],
+    publicSubnetIds: [""],
+  });
+
+  test("Distributable should be downloaded from a standard path in S3 (bucket/stack/stage/app/filename)", () => {
+    const stack = simpleGuStackForTesting();
+
+    const props: GuUserDataProps = {
+      distributable: {
+        bucketName: new GuDistributionBucketParameter(stack).valueAsString,
+        fileName: "my-app.deb",
+        executionStatement: `dpkg -i /${stack.app}/my-app.deb`,
+      },
+    };
+
+    const { userData } = new GuUserData(stack, props);
+
+    new GuAutoScalingGroup(stack, "AutoscalingGroup", {
+      vpc,
+      userData,
+      stageDependentProps: {
+        [Stage.CODE]: {
+          minimumInstances: 1,
+        },
+        [Stage.PROD]: {
+          minimumInstances: 3,
+        },
+      },
+    });
+
+    expect(stack).toHaveResource("AWS::AutoScaling::LaunchConfiguration", {
+      UserData: {
+        "Fn::Base64": {
+          "Fn::Join": [
+            "",
+            [
+              "#!/bin/bash\nmkdir -p $(dirname '/testing/my-app.deb')\naws s3 cp 's3://",
+              {
+                Ref: "DistributionBucketName",
+              },
+              "/test-stack/",
+              {
+                Ref: "Stage",
+              },
+              "/testing/my-app.deb' '/testing/my-app.deb'\ndpkg -i /testing/my-app.deb",
+            ],
+          ],
+        },
+      },
+    });
+  });
+
+  test("Distributable should download configuration first", () => {
+    const stack = simpleGuStackForTesting();
+
+    const props: GuUserDataProps = {
+      distributable: {
+        bucketName: new GuDistributionBucketParameter(stack).valueAsString,
+        fileName: "my-app.deb",
+        executionStatement: `dpkg -i /${stack.app}/my-app.deb`,
+      },
+      configuration: {
+        bucketName: "test-app-config",
+        files: ["secrets.json", "application.conf"],
+      },
+    };
+
+    const { userData } = new GuUserData(stack, props);
+
+    new GuAutoScalingGroup(stack, "AutoscalingGroup", {
+      vpc,
+      userData,
+      stageDependentProps: {
+        [Stage.CODE]: {
+          minimumInstances: 1,
+        },
+        [Stage.PROD]: {
+          minimumInstances: 3,
+        },
+      },
+    });
+
+    expect(stack).toHaveResource("AWS::AutoScaling::LaunchConfiguration", {
+      UserData: {
+        "Fn::Base64": {
+          "Fn::Join": [
+            "",
+            [
+              "#!/bin/bash\nmkdir -p $(dirname '/etc/testing/secrets.json')\naws s3 cp 's3://test-app-config/secrets.json' '/etc/testing/secrets.json'\nmkdir -p $(dirname '/etc/testing/application.conf')\naws s3 cp 's3://test-app-config/application.conf' '/etc/testing/application.conf'\nmkdir -p $(dirname '/testing/my-app.deb')\naws s3 cp 's3://",
+              {
+                Ref: "DistributionBucketName",
+              },
+              "/test-stack/",
+              {
+                Ref: "Stage",
+              },
+              "/testing/my-app.deb' '/testing/my-app.deb'\ndpkg -i /testing/my-app.deb",
+            ],
+          ],
+        },
+      },
+    });
+  });
+});

src/constructs/autoscaling/user-data.ts

@@ -1,13 +1,94 @@
 import type { S3DownloadOptions } from "@aws-cdk/aws-ec2";
 import { UserData } from "@aws-cdk/aws-ec2";
+import { Bucket } from "@aws-cdk/aws-s3";
+import type { GuStack } from "../core";
 
+/**
+ * Where to download a distributable from.
+ * We'll look for `fileName` on the path "bucket/stack/stage/app/<fileName>".
+ * `executionStatement` will be something like "dpkg -i application.deb` or `service foo start`.
+ */
+export interface GuUserDataS3DistributableProps {
+  bucketName: string;
+  fileName: string;
+  executionStatement: string; // TODO can we detect this and auto generate it? Maybe from the file extension?
+}
+
+/**
+ * Where to download configuration from.
+ * `files` are paths from the root of the bucket.
+ *   TODO change this once we have defined best practice for configuration.
+ */
+export interface GuUserDataS3ConfigurationProps {
+  bucketName: string;
+  files: string[];
+}
+
+export interface GuUserDataProps {
+  distributable: GuUserDataS3DistributableProps;
+  configuration?: GuUserDataS3ConfigurationProps;
+}
+
+/**
+ * An abstraction over UserData to simplify its creation.
+ * Especially useful for simple user data where we:
+ *   - (optional) download config
+ *   - download distributable
+ *   - execute distributable
+ */
 export class GuUserData {
-  private _userData = UserData.forLinux();
+  private readonly _userData: UserData;
 
   get userData(): UserData {
     return this._userData;
   }
 
+  private downloadDistributable(scope: GuStack, props: GuUserDataS3DistributableProps) {
+    const localDirectory = `/${scope.app}`;
+    const { bucketName, fileName } = props;
+    const bucketKey = [scope.stack, scope.stage, scope.app, fileName].join("/");
+
+    const bucket = Bucket.fromBucketAttributes(scope, "DistributionBucket", {
+      bucketName,
+    });
+
+    this.addS3DownloadCommand({
+      bucket: bucket,
+      bucketKey,
+      localFile: `${localDirectory}/${fileName}`,
+    });
+  }
+
+  private downloadConfiguration(scope: GuStack, props: GuUserDataS3ConfigurationProps) {
+    const localDirectory = `/etc/${scope.app}`;
+    const { bucketName, files } = props;
+
+    const bucket = Bucket.fromBucketAttributes(scope, `${scope.app}ConfigurationBucket`, {
+      bucketName,
+    });
+
+    files.forEach((bucketKey) => {
+      const fileName = bucketKey.split("/").slice(-1)[0];
+
+      this.addS3DownloadCommand({
+        bucket,
+        bucketKey,
+        localFile: `${localDirectory}/${fileName}`,
+      });
+    });
+  }
+
+  // eslint-disable-next-line custom-rules/valid-constructors -- TODO only lint for things that extend IConstruct
+  constructor(scope: GuStack, props?: GuUserDataProps) {
+    this._userData = UserData.forLinux();
+
+    if (props) {
+      props.configuration && this.downloadConfiguration(scope, props.configuration);
+      this.downloadDistributable(scope, props.distributable);
+      this.addCommands(props.distributable.executionStatement);
+    }
+  }
+
   addCommands(...commands: string[]): GuUserData {
     this._userData.addCommands(...commands);
     return this;