refactor: fix modularization

RafalWilinski · Aug 8, 2022 · b2f5e6e · b2f5e6e
1 parent 19efb4b
commit b2f5e6e
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Showing 6 changed files with 66 additions and 53 deletions.
diff --git a/package.json b/package.json
diff --git a/src/custom-resource-migrations-runner.ts b/src/custom-resource-migrations-runner.ts
@@ -1,41 +1,71 @@
-import { CloudFormationCustomResourceEvent } from "aws-lambda";
+import { Table as cdkTable } from "aws-cdk-lib/aws-dynamodb";
+import {
+  CloudFormationCustomResourceEvent,
+  CloudFormationCustomResourceResponse,
+  CloudFormationCustomResourceSuccessResponse,
+  CloudFormationCustomResourceFailedResponse,
+} from "aws-lambda";
 import { Construct } from "constructs";
-import { $AWS, Function } from "functionless";
+import { $AWS, Function, Table } from "functionless";
+import { MigrationHistoryItem } from "./migrations-manager";
 
 export type CustomResourceMigrationsRunnerProps = {
   migrationFiles: string[];
+  migrationsHistoryTable: Table<MigrationHistoryItem, "id">;
 };
 
 export default class CustomResourceMigrationsRunner extends Construct {
+  public readonly function: Function<
+    CloudFormationCustomResourceEvent,
+    CloudFormationCustomResourceResponse
+  >;
   constructor(
     scope: Construct,
     id: string,
     props: CustomResourceMigrationsRunnerProps
   ) {
     super(scope, id);
 
-    new Function(
+    const migrationsHistoryTable = Table.fromTable<MigrationHistoryItem, "id">(
+      cdkTable.fromTableArn(
+        scope,
+        "MigrationsHistoryTable",
+        props.migrationsHistoryTable.tableArn
+      )
+    );
+
+    this.function = new Function(
       scope,
       `${id}-MigrationsRunner`,
       async (event: CloudFormationCustomResourceEvent) => {
         console.log(event);
 
-        const migrations = await $AWS.DynamoDB.Scan({
-          Table: migrationsHistoryTable,
-        });
+        try {
+          const migrations = await $AWS.DynamoDB.Scan({
+            Table: migrationsHistoryTable,
+          });
+
+          console.log({ migrations });
 
-        console.log({ migrations });
+          const migrationsToRun = props.migrationFiles.filter(
+            (migrationFile) =>
+              !(migrations.Items ?? []).find(
+                (migration) => migration.id.S === migrationFile
+              )
+          );
 
-        const migrationsToRun = props.migrationFiles.filter(
-          (migrationFile) =>
-            !(migrations.Items ?? []).find(
-              (migration) => migration.id.S === migrationFile
-            )
-        );
+          console.log({ migrationsToRun });
 
-        console.log({ migrationsToRun });
+          // todo: Start the migrations
 
-        // todo: Start the migrations
+          return {
+            Status: "SUCCESS",
+          } as CloudFormationCustomResourceSuccessResponse;
+        } catch (error) {
+          return {
+            Status: "FAILED",
+          } as CloudFormationCustomResourceFailedResponse;
+        }
       }
     );
   }

diff --git a/src/examples/migrations/20220801-add-attribute.ts b/src/examples/migrations/20220801-add-attribute.ts
@@ -1,14 +1,7 @@
 import { Table as cdkTable } from "aws-cdk-lib/aws-dynamodb";
-import { Construct } from "constructs";
 import { $AWS, Table } from "functionless";
 import { unmarshall, marshall } from "typesafe-dynamodb/lib/marshall";
-import { MigrationProps, Migration } from "../../migration";
-
-export type MigrationFunction = (
-  scope: Construct,
-  id: string,
-  props: MigrationProps
-) => Migration<any>;
+import { Migration, MigrationFunction } from "../..";
 
 const tableArn =
   "arn:aws:dynamodb:us-east-1:085108115628:table/TestStack-TableCD117FA1-ZVV3ZWUOWPO";
@@ -20,16 +13,17 @@ export const migration: MigrationFunction = (scope, migrationName) => {
   });
 
   const table = Table.fromTable(
-    cdkTable.fromTableArn(scope, "SubjectTable", tableArn)
+    cdkTable.fromTableArn(scope, "TargetTable", tableArn)
   );
 
   // Actual migration code goes here.
   // For each item in the table
   migrationDefinition.scan(async ({ result }) => {
     for (const i of result.Items as any[]) {
-      // Do the following:
+      // Do the following
       await $AWS.DynamoDB.PutItem({
         Table: table,
+        // Add migratedAt attribute to the item
         Item: marshall({ ...unmarshall(i), migratedAt: Date.now() }),
       });
     }

diff --git a/src/examples/test-stack.ts b/src/examples/test-stack.ts
@@ -1,6 +1,6 @@
 import { App, CfnOutput, Stack } from "aws-cdk-lib";
 import { AttributeType, BillingMode, Table } from "aws-cdk-lib/aws-dynamodb";
-import { MigrationsManager } from "../app";
+import { MigrationsManager } from "../";
 
 const app = new App();
 

diff --git a/src/migration.ts b/src/migration.ts
@@ -94,3 +94,9 @@ export class Migration<T extends object> extends NestedStack {
     );
   }
 }
+
+export type MigrationFunction = (
+  scope: Construct,
+  id: string,
+  props: MigrationProps
+) => Migration<any>;
diff --git a/src/migrations-manager.ts b/src/migrations-manager.ts
@@ -2,9 +2,9 @@ import * as fs from "fs";
 import * as path from "path";
 import { aws_dynamodb, CustomResource } from "aws-cdk-lib";
 import { Provider } from "aws-cdk-lib/custom-resources";
-import { CloudFormationCustomResourceEvent } from "aws-lambda";
 import { Construct } from "constructs";
-import { $AWS, Table, Function } from "functionless";
+import { Table } from "functionless";
+import CustomResourceMigrationsRunner from "./custom-resource-migrations-runner";
 
 export type MigrationManagerProps = {
   /**
@@ -45,10 +45,10 @@ export class MigrationsManager extends Construct {
 
     const migrationsDir = path.resolve(props.migrationsDir);
     const migrationFiles = fs.readdirSync(migrationsDir);
-
     let migrationStacks = [];
 
     for (const migrationFile of migrationFiles) {
+      // Cannot use dynamic imports here due to synchronous nature of CDKs synthesis process
       // eslint-disable-next-line @typescript-eslint/no-require-imports
       const migrationStack = require(path.resolve(
         migrationsDir,
@@ -58,35 +58,17 @@ export class MigrationsManager extends Construct {
       migrationStacks.push(migrationStack.migration(this, migrationFile));
     }
 
-    const onEventHandler = new Function(
+    const onEventHandler = new CustomResourceMigrationsRunner(
       this,
-      "OnEventHandler",
-      async (event: CloudFormationCustomResourceEvent) => {
-        console.log(event);
-
-        const migrations = await $AWS.DynamoDB.Scan({
-          Table: migrationsHistoryTable,
-        });
-
-        console.log({ migrations });
-
-        const migrationsToRun = migrationFiles.filter(
-          (migrationFile) =>
-            !(migrations.Items ?? []).find(
-              (migration) => migration.id.S === migrationFile
-            )
-        );
-
-        console.log({ migrationsToRun });
-
-        // todo: Start the migrations
-      }
+      "MigrationsRunner",
+      { migrationsHistoryTable, migrationFiles }
     );
 
     const migrationsProvider = new Provider(this, "MigrationsProvider", {
-      onEventHandler: onEventHandler.resource,
+      onEventHandler: onEventHandler.function.resource,
     });
 
+    // Ensure migrations provider is ran after all nested stacks are created
     migrationStacks.map((stack) =>
       migrationsProvider.node.addDependency(stack)
     );