Pulumi SES Suppression List Bug: ConfigurationSet Update Fails
Experiencing issues with Pulumi and SES suppression lists? You're not alone. This article dives into a specific bug where Pulumi silently fails to disable SES suppression lists on existing configuration sets. We'll explore the problem, provide a sample program to reproduce it, and discuss potential causes and workarounds. Let's get started!
Understanding the Issue: Pulumi and SES Suppression Lists
When working with Amazon Simple Email Service (SES), suppression lists are crucial for maintaining a good sender reputation. They prevent you from sending emails to addresses that have bounced, complained, or unsubscribed. Pulumi, as an Infrastructure as Code (IaC) tool, allows you to manage SES configuration sets, including their suppression options. However, a bug exists where Pulumi fails to update the suppressed_reasons setting to an empty list ([]) once the resource has been created. This means that if you initially create a configuration set with certain suppression reasons enabled, you won't be able to disable them later using Pulumi. This can lead to unexpected behavior and prevent you from sending emails to intended recipients.
Let's delve deeper into the specifics of this issue and how to reproduce it.
The Problem in Detail
The core of the problem lies in Pulumi's inability to correctly process updates to the suppressed_reasons attribute within the suppression_options block of a pulumi_aws.sesv2.ConfigurationSet resource. When you attempt to change suppressed_reasons from a non-empty list to an empty list ([]), Pulumi shows a diff indicating the change, but the actual AWS resource remains unaffected. This discrepancy between the desired state in Pulumi and the actual state in AWS leads to Pulumi continuously attempting the update on subsequent runs, creating a frustrating loop. It's important to note that this issue specifically affects disabling suppression reasons; enabling them during initial creation works as expected.
This behavior can have significant implications for your email sending strategy. If you need to temporarily disable certain suppression reasons for testing or other purposes, you'll find yourself unable to do so through Pulumi. This forces you to resort to manual changes through the AWS console or other means, which defeats the purpose of using IaC in the first place. Furthermore, this issue can lead to inconsistencies between your infrastructure definition in Pulumi and the actual state in AWS, making it harder to manage and maintain your email infrastructure.
Reproducing the Bug: A Step-by-Step Guide
To illustrate the issue, let's walk through a sample program that demonstrates the bug. Follow these steps to reproduce the problem in your own Pulumi environment.
Step 1: Initial Configuration Set Creation
First, create a Pulumi program that defines a basic SES configuration set. This initial configuration will not have any suppression options explicitly set. Create a file named __main__.py (or your preferred language equivalent) with the following code:
import pulumi
import pulumi_aws.sesv2 as sesv2
example = sesv2.ConfigurationSet(
"example",
configuration_set_name="example",
)
This code defines a ConfigurationSet resource named "example" with a configuration_set_name of "example". At this stage, we are not specifying any suppression options. Run pulumi up to create the resource in your AWS account. This initial creation should succeed without any issues.
Step 2: Attempting to Disable Suppression Reasons
Now, let's modify the program to explicitly disable all suppression reasons. Update your __main__.py file with the following code:
import pulumi
import pulumi_aws.sesv2 as sesv2
example = sesv2.ConfigurationSet(
"example",
configuration_set_name="example",
suppression_options=sesv2.ConfigurationSetSuppressionOptionsArgs(
suppressed_reasons=[],
),
)
In this updated code, we've added the suppression_options block and set suppressed_reasons to an empty list ([]). This indicates our intention to disable all suppression reasons for this configuration set. Run pulumi up again. You will observe that Pulumi shows a diff indicating the change, but the update will not actually be applied to the AWS resource.
Step 3: Observing the Persistent Diff
After running pulumi up in Step 2, you'll notice that the next time you run pulumi up, Pulumi will again show the same diff, indicating that it's still trying to disable the suppression reasons. This creates a persistent diff loop, where Pulumi repeatedly attempts an update that never succeeds. This is the core symptom of the bug. This persistent diff highlights the inconsistency between Pulumi's desired state and the actual state in AWS.
By following these steps, you can easily reproduce the Pulumi SES suppression list bug and confirm that it affects your environment.
Analyzing the Root Cause: Potential Terraform Issue
The Pulumi team suspects that this issue might stem from an upstream bug within the Terraform AWS provider, which Pulumi relies on for managing AWS resources. While a definitive confirmation requires further investigation, the symptoms strongly suggest a problem in how Terraform handles updates to the suppressed_reasons attribute. It's possible that Terraform is not correctly translating the empty list ([]) into the appropriate API call to disable suppression reasons in SES.
If the root cause indeed lies within Terraform, the fix would need to be implemented in the Terraform AWS provider and then incorporated into Pulumi. This highlights the importance of understanding the underlying providers that IaC tools like Pulumi depend on. While Pulumi provides a convenient abstraction layer, issues in the underlying providers can still impact your infrastructure management.
Workarounds and Solutions: Temporary Measures
While a permanent fix is being investigated, here are a few potential workarounds you can consider:
- Manual Update via AWS Console: The most direct workaround is to manually disable the suppression reasons through the AWS SES console. This allows you to achieve the desired state, but it bypasses Pulumi and introduces manual steps into your infrastructure management process. This approach should be considered a temporary measure as it deviates from the principles of IaC.
- AWS CLI or SDK: You can use the AWS Command Line Interface (CLI) or the AWS SDK to programmatically update the suppression options. This approach is more aligned with IaC principles than manual updates, but it requires you to write additional code outside of your Pulumi program. This workaround offers more automation but adds complexity to your deployment process.
- Avoid Disabling Suppression Reasons (If Possible): If your use case allows, you might consider designing your email sending strategy to minimize the need to disable suppression reasons. This could involve more careful management of your recipient lists and adherence to best practices for email deliverability. This proactive approach can help you avoid the bug altogether, but it might not be feasible in all situations.
Conclusion: Staying Informed and Contributing
The Pulumi SES suppression list bug highlights the complexities of managing cloud infrastructure and the importance of staying informed about potential issues. While a permanent fix is being worked on, the workarounds discussed above can help you mitigate the impact of this bug. It's crucial to remember that IaC tools like Pulumi are constantly evolving, and bugs can occur. By understanding the underlying mechanisms and potential workarounds, you can effectively manage your infrastructure even in the face of unexpected issues.
We encourage you to stay updated on the progress of this issue by following the relevant discussions on the Pulumi and Terraform forums. Your contributions, whether through reporting bugs, providing feedback, or even submitting code, can help improve the overall quality of these tools.
For further information on AWS SES and suppression lists, you can refer to the official AWS documentation: Amazon SES Suppression List
