Using characteristic flags and different runtime configuration varieties is a fast-evolving know-how section. Adjusting your software program conduct with a minor configuration replace as a substitute of deploying code lets groups transfer quicker and extra safely. Furthermore, releasing a characteristic utilizing a characteristic flag permits engineering groups to activate options to a restricted set of customers after which measure the affect. The functionality can immediately flip off and roll again if one thing goes flawed, considerably limiting the change’s affect. At Amazon, we name the follow of utilizing characteristic flags and runtime configuration, Continuous Configuration.
AWS AppConfig began in 2017 as an inside instrument for Amazon. It rapidly grew to become a top-used service for inside groups that wished a protected and measured strategy to handle their characteristic flags and operational flags. In 2019, AWS launched AppConfig for exterior clients. This providing had all the discovered classes and greatest practices for using runtime configuration and have flags constructed into the product. Now we’re asserting AppConfig Extensions, which permits clients to increase the facility of dynamic configuration and have flags in new and revolutionary methods. After studying this put up, you’ll perceive what AppConfig Extensions are, what issues they remedy, and what extension varieties you may construct.
What are AppConfig Extensions?
Since the inner launch of AppConfig in 2017, and the exterior launch in 2019, we’ve added many options that clients have requested. These embody integrations with Lambda, AWS CodePipeline, and Amazon CloudWatch, in addition to releasing an opinionated format for characteristic flags in 2021. We’ve innovated on behalf of our clients, and we frequently obtain many requests for brand spanking new performance. One statement we’ve had on these requests is that there are points to them that make them impractical to construct in a generic approach. Another statement was seeing how some clients have constructed options on prime of our service in ways in which have been particular to their very own workflows. However, as a substitute of getting the AppConfig group construct all new options as requested, we determined to empower others to construct on prime of AppConfig. We knew that permitting different engineers, each inside and exterior, to make the most of a framework to increase AppConfig could be a drive multiplier, plus give the liberty to assist integrations into customer-specific programs and processes.
AppConfig Extensions are add-ons to AppConfig that improve the facility and security of the principle AppConfig service. Managing configuration sometimes follows a lifecycle just like growing code: create/replace, validate/check, deploy, and monitor. The AppConfig Extension framework exposes hooks, known as motion factors, at every of those lifecycle milestones. When an motion level is triggered, no matter actions (e.g. calling a Lambda operate) are outlined within the set of AppConfig Extensions relevant at that lifecycle step shall be invoked.
The framework permits for simpler integration of different providers (AWS and in any other case) to assist clients enhance their velocity and security. Over the approaching months and years, we anticipate the variety of extensions to develop considerably, offering bespoke options created by AWS and our clients.
Self-authored AppConfig Extensions
To present a way of the performance that AppConfig Extensions can present, we’ll illustrate some examples comparable to the lifecycle steps talked about above, beginning with the primary part: the creation of configuration information. Let’s say, for instance, that you just wished so as to add a timestamp inside your hosted configuration information’s JSON every time it will get up to date. With an extension, you would hook into the PRE_CREATE_HOSTED_CONFIGURATION_VERSION motion level and write a easy AWS Lambda to insert the timestamp. You could subsequent determine that you just need to export a duplicate of every model of your hosted configuration information right into a supply repository like Github, no matter its information format. You may create one other extension that additionally hooks into the PRE_CREATE_HOSTED_CONFIGURATION_VERSION motion level to export the hosted information into your repo each time the info adjustments. While each extensions may very well be related to a selected Configuration Profile, you would as a substitute affiliate this extension to an Application which is able to trigger it to robotically apply to all hosted Configuration Profiles in your Application, even these created at a later date. Continuing down the lifecycle steps, you would possibly must merge information from one other supply, equivalent to a legacy configuration database, into your configuration information earlier than it deploys. Your extension would comprise an motion that triggers at PRE_START_DEPLOYMENT and calls a Lambda to retrieve the info and merge it into the to-be-deployed model of configuration information. As a last instance, you would set off check automation to run after you’ve deployed new configuration information by hooking into the ON_DEPLOYMENT_COMPLETE motion level that publishes a message to an SNS matter.
Available Action Points
As famous above, an extension can hook into AppConfig Extension motion factors. Currently, AppConfig exposes the next motion factors:
| Action level | Description |
| PRE_CREATE_HOSTED_CONFIGURATION_VERSION | happens when an AppConfig hosted configuration is created or up to date, however simply earlier than it’s saved |
| PRE_START_DEPLOYMENT | happens simply earlier than a deployment begins |
| ON_DEPLOYMENT_START | happens when an AppConfig deployment begins |
| ON_DEPLOYMENT_STEP | happens throughout a deployment, and increments relying on the deployment technique step share |
| ON_DEPLOYMENT_BAKING | happens after the deployment completes, however bake time (if specified) begins |
| ON_DEPLOYMENT_COMPLETE | happens after the deployment and bake time is full |
| ON_DEPLOYMENT_ROLLED_BACK | happens if a deployment roll again initiates |
AWS-authored AppConfig Extensions
In addition to the AppConfig extensions you create, we have now a handful of extensions which are already accessible so that you can use. The AppConfig Notification Extensions enable clients to be notified for the ON_DEPLOYMENT_START, ON_DEPLOYMENT_COMPLETE, and ON_DEPLOYMENT_ROLLEDBACK motion factors. Customers can have these notifications despatched to Amazon EventBridge, Amazon Simple Notification Service (Amazon SNS), or Amazon Simple Queue Service (Amazon SQS). We even have an AppConfig Feature Flags Helper extension, which performs a task in our Feature Flags characteristic and is robotically related to Feature Flag Configuration Profiles, in addition to a Jira Integration extension that creates and manages Jira Issues related to your characteristic flags.
Looking forward
This preliminary launch of AppConfig Extensions lays the muse for the platforming of configuration information and have flags. However, that is simply the beginning. In the longer term, we anticipate to launch many AWS-owned extensions and a few third-party extensions. Moreover, we’re trying ahead to speaking to clients concerning the extensions they’ve authored, and persevering with to innovate with our clients in how they’re using characteristic flags and runtime configuration.
Get began with AWS AppConfig Extensions.
By Steve Rice and Jonathan (JT) Thompson
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