Service Discovery

Service discovery is used in service-oriented architectures to dynamically detect and connect services within a network. At FlexStack, you get this out-of-the-box.

When you create an environment in FlexStack, we set up your network with Service Discovery enabled. There are two ways to use it:

  • If you're communicating between services within the cluster (for example, between web services and private services) you can use proxy addresses. A service's proxy address can be found under the "Internal service URL" heading on a component overview page. In the example below, calling http://ingest.flexstack.internal:8080 from another service within the cluster to hit the "ingest" service on port 8080.
A screen grab of the Internal Service URL
  • If you would like to call a service from outside the cluster, but within the private network (for example, from a serverless function) you may use the address dns.[COMPONENT_NAME].[PROJECT_NAME]-[ENVIRONMENT_NAME].internal:[PORT] to use DNS queries for discovery, or dns.ingest.[PROJECT_NAME]-[ENVIRONMENT_NAME].internal:8080 using the same example above. To select a specific or random healthy instance within the namespace, you can use the AWS CloudMap DiscoverInstances API. Here is an example using TypeScript. In this example, the ServiceName property would be ingest and the NamespaceName property would be [PROJECT_NAME]-[ENVIRONMENT_NAME].internal.

How it works

The architecture for this is pretty straightforward. Every container service you create in FlexStack gets registered in AWS CloudMap and AWS ECS Service Connect. In the case of Service Connect, every port you expose in your service gets its own address in service connect at [PORT_NAME].[COMPONENT_NAME].[PROJECT_NAME]-[ENVIRONMENT_NAME].internal.

You can programmatically access the discovery DNS namespace in your application using the FLEXSTACK_DISCOVERY_NAMESPACE environment variable.

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