Source code: https://git.io/fjEzw
In our last blog post we created API for our book catalog. But all the data is hard-coded in lambda functions. So lets make changes to it so that we can use a database for persisting book catalog data.
Amazon has a service called DynamoDB, which is a NoSQL database hosted and managed by AWS.
We will be using this for our backend data persistence.
1. DATABASE SETUP
Let’s start with setting up our database. Login to console and open DynamoDB service. You will see the Dashboard page as show below
Click on Create Table button
After a while, a table will be created as follows
If you click Items tab, you will see that there are no items present right now
Now lets add one item here. Click on Create item button and add the following data
We created only one field/column in our table called “id”. That is because NoSQL databases have the option of having dynamic schema where each row/record can have different columns.
So add 3 other columns using + button > Append > String options
Click Save button. Now you should be able to see the new item like shown below
This complets our database setup. Now lets continue with our project setup
2. PROJECT SETUP
Create Blog11 folder in your IDE as shown below and copy the files from GitHub and place it here, as shown below
Changes have been made to these files so that they can now interact with our DynamoDB table we created above. We are still doing basic CRUD operations and hence have 4 handler files in handlers folder for each operation.
Index.js is our main handler file that receives API requests and routes it to appropriate handler
Now, lets take a look at get-book.js file
Here we can see the changes have been made to use the AWS.DynamoDB. DocumentClient library to interact with DynamoDB database from the code. If this code is passed parameter bookid, it will return one book. Otherwise it will return All books.
3. DEPLOYMENT
We will now deploy this api project using the easy deployment method we have seen till now,i.e. using Claudia.js framework.
npm init
Type yes and ENTER to confirm.
Install claudia.js framework
npm install -g claudia
Install claudia api builder
npm install claudia-api-builder -s
We also have to install aws sdk for javascript.
npm install aws-sdk
Now, lets deploy our API
claudia create –region us-east-1 –api-module index
This completes the deploymetn and we have got URL for accessing our API, as shown above
4. DEPLOYMENT CHECK
First lets check whether deployment was done correctly and artifacts are visible in AWS Console
Now open Postman API testing tool and hit /books URL
You will see that it was Not successful and we get the below error.
This is correct. We have Not given permission to our role “books-catalog-api-executor” to access DynamoDB and hence it cnanot access it. So lets fix it by creating the correct policy that has right permissions to access DynamoDB and attach that policy to our api role.
5. SET PERMISSIONS
Go to AWS IAM and click Policies and then click Create policy button
Click JSON tab in below window and ignore the message shown.
Now paste the following policy statement in it
This policies allow CRUD operations on DynamoDb database. You can find this in a file called dynamodb.json in policies folder. Paste this in side JSON tab and click Review policy button
Then click Create policy button. Enter Name and Description and click Create policy button
Now we have to attach this policy to our Role.
Click Roles and find and open books-catalog-api-executor role
Click Attach policy button and select our newly created plolicy BasicDynamoDBPermissions and click Attach policy button
You can see now that our Role has two policies attached to it.
That’s it. Permissoins have been given so now let’s resume testing
6. TESTING
1. Get all books
Method: GET
Url: https://wgf1dr1rv0.execute-api.us-east-1.amazonaws.com/latest/books
Result:
2. Add a new book
Method POST
Url: https://wgf1dr1rv0.execute-api.us-east-1.amazonaws.com/latest/bookadd
Payload:
Result:
We can verify whether the book is added by calling GET again
3. Get a single book
Method PUT
Url: https://wgf1dr1rv0.execute-api.us-east-1.amazonaws.com/latest/books/2
Result
4. Update a book’s details.
Lets change price of Redemption book to 13.95
Method PUT
Url: https://wgf1dr1rv0.execute-api.us-east-1.amazonaws.com/latest/bookupdate/2
Payload:
Result:
We can verify by going to DynamoDb database
5. Delete a book
Lets delete Redemption book
Method DELETE
Url: https://wgf1dr1rv0.execute-api.us-east-1.amazonaws.com/latest/bookdelete/2
Result:
That’s it. We are done.
7. Clean up:
To cleanup, execute the following command
claudia destroy
This will Not cleanup (delete) table we created in DynamoDB (books-catalog). So make sure to delete the table manually.
8. Conclusion
So now, our API’s has ability to store and retrieve data usign a NoSQL database on AWS called DynamoDB.
Happy Clouding!
Adventures In Cloud 