Category Archives: Autonomous

How To Connect your Node.js app in Docker to your Oracle Database

In this post I’ll cover how to make a connection from a Node.js application in a Docker container to your Oracle Database in three different scenarios.

  • Typical Database connection.
  • Database inside a different Docker container.
  • Oracle Autonomous Transaction Processing Cloud Database.

Simple Test App

When attempting something new, I find it’s best to make sure all of the pieces that are not part of the new thing, are as simple as possible.

For my examples I will be using a small Node.js application that:

  • Connects to the Oracle Database.
  • Runs a simple query.
  • Prints the results to the console.

Create a new file named dbConfig.js to set the database connection information.

Create a new file named server.js used to test the connection.

Install the node-oracledb driver. (If you have any questions about the node-oracledb driver, you can find the answers here.)

Create environment variables for the connection information.  (Replace my values with yours)

Test the Node.js application.  You should see something similar to the following.

Create a Docker Container for the Node.js app

Create a Dockerfile

Build the image

Now that you have an image you’ll run a container and to connect it to:

Typical Oracle Database
The container will run, execute the query and stop.  You should see something similar to this output.
An Oracle Database inside a Docker Container

In a previous post I walked through how to setup both an ORDS instance and an Oracle XE instance in Docker Containers.  Follow through the section showing how to create an Oracle XE Database in a Docker container.

When you followed the steps in that post you should have also created a Docker Network.

You’ll use that same network to connect from the Node.js container to the Oracle XE container.

First, change your NODE_ORACLEDB_CONNECTIONSTRING environment variable to use the Oracle XE container name.

Now when you run a new docker container you will attach it to the same Docker Network as the Oracle XE container.

The container will run, execute the query and stop.  You should see something similar to this output.

Since both containers are using the same Docker network, you do not need to open the port when you run the Oracle XE container.  This is useful if you’d like to keep your database private inside the Docker environment.

Oracle Autonomous Transaction Processing Cloud Database

After you create an Oracle ATP Cloud Database you’ll need to download the credentials file and extract it into a secure location.

For this database, you will be using an entry in the tnsnames.ora file to make the database connection.  Change the NODE_ORACLEDB_CONNECTIONSTRING environment variable to use the tnsnames entry:

Before you run the container, you need to modify the sqlnet.ora file found in the credentials directory.  Change the wallet location to the value that will be mapped inside the Docker container.

When you run the new container for the node app you will map a volume from the directory where you extracted your credentials file to the internal container directory.  Mapping a volume makes sure that there is not a copy of the credential files inside the Docker container.

Finally, when you run the new container, you will add an additional environment variable defining where the tns admin information is located.

The full command looks like this:

The container will run, execute the query and stop.  You should see something similar to this output.

I used the same docker image for all of the examples

You may have noticed that you only built the Docker image once at the beginning of the post.  The application in the Docker image uses environment variables to connect to the database.  This allows you to run the same application in one or more containers and each container can connect to different Oracle Databases without having to rebuild the image.

Oracle REST Data Services on Autonomous Transaction Processing Database

Whenever I give a presentation, write a blog post or make a video I like to run all of my examples and demos locally and on an Oracle Cloud instance.  I keep a Virtual Box machine or Docker Container ready on my laptop, just in case I can’t get to the internet, but for speed and dependability, you just can’t beat a cloud instance.

I like to have some automation scripts handy to create and destroy my environments and depending on what I’m doing that can sometimes take a while.

So when Oracle’s Autonomous Transaction Processing Database was released I was excited by how fast I could spin up a new instance.  It takes a few minutes instead of around an hour for other options.  Oracle wanted to make sure ATP was solid, so they initially launched with a limited feature set and new features have been making their way into Oracle’s Autonomous Transaction Processing Database almost every month.

At KScope19 it was announced that Oracle REST Data Services is now available on ATP.

I was scheduled to give my ‘Creating REST APIs Is Fast, Easy, and Secure with Oracle REST Data Services‘ talk on Wednesday and I like to live dangerously, so I decide (Tuesday afternoon) to convert my demos over to ORDS on ATP.  I figured worst case, if I couldn’t figure it out I’d just use my Docker container.

It’s going to be hard… right?

I already had a couple of ATP instances that I use for stuff and things.  Since I wanted to do a live demo, I decided to spin up a new instance just in case I expose anything that could be used to get in.  It took under 5 minutes to fully create and start up a brand new ATP database.  After that, I downloaded my Client Credentials (Wallet) and connected with SQL Developer.  There are lots of examples for this part so I’ll move on to the new stuff.

New User

I try to do as little as possible as the Admin user so I created a rest_demo user with a couple of tables and a view.

Create a test API

Then I used the SQL Developer ‘Auto REST’ feature to REST enable the schema and a table.   (PL/SQL exported below in case you want to try it.)

Get the URI

Now I just needed the URI to test my new service.  Here are the steps:

  1. Log into your Oracle Cloud Dashboard.
  2. From the menu, select ‘Autonomous Transaction Processing’.
  3. From the instance menu, select ‘Service Console’.

    Or, Click on your Instance Name then Click the ‘Service Console’ button.
  4. Click ‘Administration’.
  5. In the Rest Data Services box, click either button.
  6. Copy from the beginning of the URL up to and including ‘/ords/’
    https://someIdstuff-blaineords.adb.my-region-1.oraclecloudapps.com/ords/
    Ignore the rest.
Test it

For a simple fast test, I just used an internet browser with the following URI:
https://someIdstuff-blaineords.adb.my-region-1.oraclecloudapps.com/ords/api/cool_data

Well, that was easy.

To be honest I expected this to be a lot harder and that I’d have problems.  I ran through all of the demos for my presentation and they just worked, first try.

The thing I spent the most time on was re-checking everything.  Since it was so easy, I thought I had connected to one of my pre-existing cloud databases.

Go try it!

As always, don’t take my word for it, go try it yourself.

Here are some links to help get you going: