botocore.exceptions.NoRegionError: You must specify a region

# Table of Contents

1. botocore.exceptions.NoRegionError: You must specify a region
2. Passing the region_name argument when creating the boto3 client
3. Setting the default region in your ~/.aws/config file
4. Setting the AWS_DEFAULT_REGION environment variable in your shell
5. Setting the AWS_DEFAULT_REGION environment variable in your Python script
6. Creating the client in the same region as your Lambda function

# botocore.exceptions.NoRegionError: You must specify a region

The AWS and boto3 "botocore.exceptions.NoRegionError: You must specify a region" error occurs because you must specify the region in which the boto3 client should be created.

You can set the region in multiple ways:

1. By passing the region_name argument when creating the boto3 client.
2. By specifying a default region in your ~/.aws/config file.
3. By setting the AWS_DEFAULT_REGION environment variable via your shell.
4. By setting the AWS_DEFAULT_REGION environment variable in your Python script.

# Passing the region_name argument when creating the boto3 client

One way to solve the error is to pass the region_name argument when creating the boto3 client.

Here is an example that does that when creating an s3 client.

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import boto3

region = 'us-east-1'

s3_client = boto3.client('s3', region_name=region)

# 👇️ print region name
print(s3_client.meta.region_name)

print(s3_client)

The boto3.client() method creates a low-level service client.

The method takes a region_name argument that determines in which region the client should be created.

I used us-east-1 in the example, but you can use any other region.

# Setting the default region in your ~/.aws/config file

Alternatively, you can set the default region directly in your ~/.aws/config configuration file.

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[default]
region = us-east-1

The ~/.aws/config path is a shorthand for /home/YOUR_USER/.aws/config.

You can use gedit, nano or vim to edit your config file and add the default region.

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# gedit
sudo gedit ~/.aws/config

# nano
sudo nano ~/.aws/config

# vim
sudo vim ~/.aws/config

Once you open the file in your preferred text editor, set your default region.

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[default]
region = us-east-1

Once you've set your default region in ~/.aws/config, you are no longer required to provide the region_name argument when creating a client.

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import boto3

region = 'us-east-1'

s3_client = boto3.client('s3')

print(s3_client.meta.region_name)

print(s3_client)

As shown in the code sample, the region is taken from my ~/.aws/config file.

You can also run the aws configure command in your shell to set your default AWS region.

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aws configure

Press Enter until you get prompted for the region and specify your preferred default region.

# Setting the AWS_DEFAULT_REGION environment variable in your shell

You can also specify the default region by setting the AWS_DEFAULT_REGION environment variable in your shell.

If you are on macOS or Linux, issue the following command.

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export AWS_DEFAULT_REGION=us-east-1

The next time you create a boto3 client, the default region will be taken from the value of your AWS_DEFAULT_REGION environment variable.

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import boto3

s3_client = boto3.client('s3')

print(s3_client.meta.region_name)

print(s3_client)

If you need to set the environment variable in a Docker container, you would use the ENV prefix.

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ENV AWS_DEFAULT_REGION=us-east-1

# Setting the AWS_DEFAULT_REGION environment variable in your Python script

You can also set the AWS_DEFAULT_REGION environment variable directly in your Python script.

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import os
import boto3

os.environ['AWS_DEFAULT_REGION'] = 'us-east-1'

s3_client = boto3.client('s3')

print(s3_client.meta.region_name) # 👉️ us-east-1

print(s3_client)

The code sample uses the os.environ mapping object to set the AWS_DEFAULT_REGION environment variable to us-east-1.

Note that the line that sets the environment variable has to run before you create your boto3 client.

# Creating the client in the same region as your Lambda function

If you need to create the boto3 client in the same region as your Lambda function, access the AWS_REGION environment variable to get the current region.

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import os
import boto3


def main(event, context):
    lambda_region = os.environ['AWS_REGION']

    print(f'Lambda function region {lambda_region}')

    s3_client = boto3.client('s3', region_name=lambda_region)

Once you get the current Lambda region, supply the region_name argument in the call to boto3.client().

I've also written an article on how to solve the error when using the AWS CLI.

# Additional Resources

You can learn more about the related topics by checking out the following tutorials:

• AWS CDK Tutorial for Beginners - Step-by-Step Guide
• AWS CDK Tutorial for Beginners - Step-by-Step Guide
• How to use Parameters in AWS CDK
• Cannot find module (AWS Lambda Error) [Solved]
• How to handle Errors in AWS Lambda using Typescript
• Making Http Requests in a Node.js Lambda Function