add more documentation for AppConfig setup

README.md

@@ -29,10 +29,16 @@ in the `local.env.dist` file. Optionally, you can define configuration in AWS Ap
 To do this, set the following environment variables to point to the configuration in
 AWS:
 
+* `AWS_REGION` - the AWS region in use
 * `APP_ID` - the application ID or name
 * `CONFIG_ID` - the configuration profile ID or name
 * `ENV_ID` - the environment ID or name
 
+In addition, the AWS PHP SDK requires authentication. It is best to use an access role
+such as an [ECS Task Role](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-iam-roles.html).
+If that is not an option, you can specify an access token using the `AWS_ACCESS_KEY_ID` and
+`AWS_SECRET_ACCESS_KEY` variables.
+
 The content of the configuration profile takes the form of a typical .env file, using
 `#` for comments and `=` for variable assignment. Any variables read from AppConfig 
 will overwrite variables set in the execution environment.

local.env.dist

@@ -18,6 +18,21 @@
 IDP_NAME=
 
 
+# === AWS AppConfig ===
+
+# The AWS region in use
+AWS_REGION
+
+# The AppConfig Application ID (or name)
+APP_ID
+
+# The AppConfig Configuration Profile ID (or name)
+CONFIG_ID
+
+# The AppConfig Environment ID (or name)
+ENV_ID
+
+
 # === email template data ===
 
 # The user-friendly version of the name of this IdP. For example: