AWS DynamoDB: How to install locally in Ubuntu?

It is possible to install dynamodb locally,lets explore how.

First Download jar file

wget https://d1ni2b6xgvw0s0.cloudfront.net/v2.x/dynamodb_local_latest.tar.gz

Now extract the the archieve.

Rename extracted folder as dynamodb

Copy it to location where you want to install binary

mv dynamodb /usr/share/

Now on command line go to folder in which dynamodb is copied,

in this case /usr/share/dynamodb.

cd /usr/share/dynamodb

Test i it runs from terminal by running this

sudo java -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb

Now if you want to test the server each time you would have to run this command

To keep it running each time without running manually we need a service.

To create a service

sudo nano /etc/systemd/system/dynamodb.service

add ollowing to it

[Unit]

Description=DynamoDB Service

[Service]

User=root

WorkingDirectory=/usr/share/dynamodb

ExecStart=/usr/share/dynamodb/dynamodb.sh

SuccessExitStatus=143

TimeoutStopSec=10

Restart=on-failure

RestartSec=5

[Install]

WantedBy=multi-user.target

save & exit

Now we will create a shell script file referred in service above.

cd /usr/share/dynamodb

nano dynamodb.sh

add

#!/bin/sh

sudo java -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb

save and exit.

Make shell script executable file

chmod u+x dynamodb.sh

Now let system know that we have created a new service

sudo systemctl daemon-reload

sudo systemctl enable dynamodb

sudo systemctl start dynamodb

sudo systemctl status dynamodb

output of last command in my case is like below

● dynamodb.service - Dynamo DB Local Service

Loaded: loaded (/etc/systemd/system/dynamodb.service; enabled; vendor preset: enabled)

Active: active (running) since Sat 2024-05-04 11:13:52 IST; 11min ago

Main PID: 33499 (dynamodb.sh)

Tasks: 41 (limit: 18708)

Memory: 150.8M

CPU: 4.333s

CGroup: /system.slice/dynamodb.service

├─33499 /bin/sh /usr/share/dynamodb/dynamodb.sh

├─33500 sudo java -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb

└─33501 java -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb

May 04 11:13:52 sangram-Inspiron-14-5430 sudo[33500]: root : PWD=/usr/share/dynamodb ; USER=root ; COMMAND=/usr/bin/java -Djava.library.path=./DynamoDBLocal_lib -jar DynamoDBLocal.jar -sharedDb

May 04 11:13:52 sangram-Inspiron-14-5430 sudo[33500]: pam_unix(sudo:session): session opened for user root(uid=0) by (uid=0)

May 04 11:13:53 sangram-Inspiron-14-5430 dynamodb.sh[33501]: Initializing DynamoDB Local with the following configuration:

May 04 11:13:53 sangram-Inspiron-14-5430 dynamodb.sh[33501]: Port: 8000

May 04 11:13:53 sangram-Inspiron-14-5430 dynamodb.sh[33501]: InMemory: false

May 04 11:13:53 sangram-Inspiron-14-5430 dynamodb.sh[33501]: Version: 2.4.0

May 04 11:13:53 sangram-Inspiron-14-5430 dynamodb.sh[33501]: DbPath: null

May 04 11:13:53 sangram-Inspiron-14-5430 dynamodb.sh[33501]: SharedDb: true

May 04 11:13:53 sangram-Inspiron-14-5430 dynamodb.sh[33501]: shouldDelayTransientStatuses: false

May 04 11:13:53 sangram-Inspiron-14-5430 dynamodb.sh[33501]: CorsParams: null

Now we need to install awscli on ubuntu as ollows

curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip"

-o "awscliv2.zip"

unzip awscliv2.zip

sudo ./aws/install

Now run aws configure

and give below response to when prompted.

AWS Access Key ID [****************yId"]: fakeMyKeyId

AWS Secret Access Key [****************Key"]: fakeSecretAccessKey

Default region name ["fakeRegion"]: fakeRegion

Default output format [None]:

The response need to be given as given above.

Now you can check lists o tables in dynamodb by running follwoing command

aws dynamodb list-tables --endpoint-url http://localhost:8000

You may also like to check how to do CRUD oprtion in dynamoDb using exprress

https://msdotnetbuddy.blogspot.com/2023/05/working-with-dynamo-db.html.

References:

https://medium.com/aws-lambda-serverless-developer-guide-with-hands/

amazon-dynamodb-primary-key-partition-key-and-sort-key-how-to-choose-right-

key-for-dynamodb-ea5673cb87c0

Sequelize-Postgres-Express:Upload file to database

Today we will explore how to upload an file (image) into

mysql database using sequelize.

Lets first create a express application using express generator.

express --view=ejs express-postgres-upload-file

Here is my package.json whivh you can check to install required npm

packages,

{

"name": "express-mysql-upload-file",

"version": "0.0.0",

"private": true,

"scripts": {

"start": "node ./bin/www"

},

"dependencies": {

"cookie-parser": "~1.4.4",

"debug": "~2.6.9",

"dotenv": "^16.4.5",

"ejs": "~2.6.1",

"express": "~4.16.1",

"http-errors": "~1.6.3",

"morgan": "~1.9.1",

"multer": "^1.4.5-lts.1",

"pg": "^8.11.5",

"sequelize": "^6.37.3"

}

}

Here we are installing multer,dotenv,sequelize,mysql2 packages.

Run npm i.

create .env file in root folder with content

PG_USER=sangram

PG_PASSWORD="sangram#81"

PG_PORT=5432

PG_DATABASE=playground

PG_SERVER=localhost

Now add upload.js in root folder with ollowing content.

var multer = require("multer");

var storage = multer.diskStorage({

destination: (req, file, cb) => {

cb(null, "./public/uploads/profile_pic/");

},

filename: function (req, file, cb) {

var fileparts = file.originalname.split(".");

var ext = fileparts[fileparts.length - 1];

cb(null, file.fieldname + "-" + Date.now() + "." + ext);

},

});

var upload = multer({ storage: storage });

module.exports = upload;

create models folder in root location & add image.js in it.

module.exports = function (sequelize, DataTypes) {

const Image = sequelize.define('image', {

imageId: {

type: DataTypes.INTEGER,

autoIncrement: true,

primaryKey: true

},

mimeType: {

type: DataTypes.STRING,

},

fileName: {

type: DataTypes.STRING,

field: 'name'

},

data: {

type: DataTypes.BLOB("long"),

}

}, {

freezeTableName: true

});

return Image;

}

Now create index.js inside model folder with following content

let { sequelize, Sequelize } = require("../connection.js");

let db = {};

db.Images = require("./image.js")(Sequelize,sequelize);

db.Sequelize = Sequelize;

db.sequelize = sequelize;

module.exports = db;

Now add uploads folder in public folder & inside uploads folder

add profile_pic folder.

Now create demo.js inside rotes folder with following content.

var express = require("express");

var router = express.Router();

var db = require("../models");

var upload = require("../uploads");

var fs = require("fs");

var path = require("path");

router.post("/", upload.single("image"), async (req, res, next) => {

try {

let imageCreated = await db.Images.create({

mimeType: req.file.mimetype,

fileName: req.file.filename,

data: fs.readFileSync(

path.join("./public/uploads/profile_pic/" + req.file.filename)

),

});

res.json({

success: true,

message: "File Uploaded to Mysql Successfully",

data: imageCreated,

});

} catch (exp) {

res.json({ success: false, message: exp.message.toString() });

}

});

router.get("/:fileId", async (req, res) => {

try {

var imageFound = await db.Images.findOne({

where: { imageId: req.params.fileId },

});

var buffer = imageFound.data;

var mimeType = imageFound.mimeType;

res.contentType(mimeType);

res.send(buffer);

} catch (exp) {

res.json({ success: false, message: exp.message.toString() });

}

});

module.exports = router;

Inside app.js add

var demoRouter = require('./routes/demo');

and

app.use('/demo', demoRouter);

in suitable location.

Now we are ready to run our application.Usually testing can be done using

postman.

For uploading image

curl --location 'http://localhost:3000/demo' \

--form 'image=@"/home/sangram/Pictures/Photo.jpg"'

Output:

{

"success": true,

"message": "File Uploaded to Mysql Successfully",

"data": {

"imageId": 1,

"mimeType": "image/jpeg",

"fileName": "image-1714485923005.jpg",

"data":{contain binary data},

"updatedAt": "2024-04-30T13:07:35.512Z",

"createdAt": "2024-04-30T13:07:35.512Z"

}

}

Please notice imageId that we are going to use in next api call.

curl --location 'http://localhost:3000/demo/1'

This will output image uploaded in previous step.

The complete code of this application can be found at

https://github.com/gitsangramdesai/express-sequelize-pg-upload-file