04 DynamoDB

DynamoDB

Diagram

Create DynamoDB

code ./stacks/resources/table.ts

import { Table, Stack } from "@serverless-stack/resources";

export const createTable = (stack: Stack) =>
  new Table(stack, "table", {
    fields: {
      id: "string",
    },
    primaryIndex: { partitionKey: "id" },
  });

Update queue

code ./stacks/resources/queue.ts

import { ..., Table } from "@serverless-stack/resources";
...

type CreateQueueOptions = { bucket: Bucket; table: Table };

...

export const createQueue: CreateQueue = (stack, { bucket, table }) => {
  ...

  const queue = new Queue(stack, "queue", {
    consumer: {
      function: {
        ...
        environment: {
          table: table.tableName,
        },
      },
    },
  });

  queue.attachPermissions([bucket, table]);

  return queue;
};

Save process on table

code ./services/functions/process.ts

...
import { ..., DynamoDB } from "aws-sdk";

...

const dynamoDb = new DynamoDB.DocumentClient();

const getLabels = async (...) => {
  ...
};

const saveLabels = async (
  key: string,
  labels?: Rekognition.Types.DetectLabelsResponse,
  error?: AWSError
) => {
  try {
    const params = {
      TableName: String(process.env.table),
      Item: {
        id: key,
        createdAt: Date.now(),
        labels,
        error,
      },
    };
    const result = await dynamoDb.put(params).promise();
    console.log("Labels have been saved");
    return result;
  } catch (error) {
    console.log(error);
  }
};

const deleteImage = async (...) => {
  ...
};

export const handler: SQSHandler = async (sqsEvent) => {
  sqsEvent.Records.forEach(async (record) => {
    ...
    const { key } = detail.object;
    try {
      const labels = await getLabels(detail);
      await saveLabels(key, labels);
    } catch (error) {
      const awsError = error as AWSError;
      await saveLabels(key, undefined, awsError);
    } finally {
      await deleteImage(detail);
    }
  });
};

Update resources index

code ./stacks/resources/index.ts

...
export * from "./table";

Update stack

code ./stacks/MyStack.ts

...
import {
  ...
  createTable,
} from "./resources";

export function MyStack({ stack }: StackContext) {
  const bucket = createBucket(stack);
  const table = createTable(stack);
  const queue = createQueue(stack, { bucket, table });
  const bus = createBus(stack, { bucket, queue });
}

Deploy changes

npm start # or press ENTER to redeploy if SST is already running

Test on SST Console

open https://console.sst.dev/sst-rekognition/sst-jp/local

Commit

git add .
git commit -m "Dynamo DB"

Next step

API Gateway