Run an Image With an Immutable Configuration

This section describes how to add a basic route to your local IG configuration folder, copy it into a new Docker image, and run that Docker image.

Unlike the previous example, the Docker image is immutable. If you change your configuration locally, the Docker image is not changed.

Use this procedure to manage configuration within the Docker image. For example, use it when you want to deploy the same configuration multiple times.

Add the following route to your local IG configuration as $HOME/.openig/config/routes/hello.json:

{
  "name": "hello",
  "handler": {
    "type": "StaticResponseHandler",
    "config": {
      "status": 200,
      "reason": "OK",
      "headers": {
        "Content-Type": [ "text/plain" ]
      },
      "entity": "Hello world!"
    }
  },
  "condition": "${matches(request.uri.path, '^/hello')}"
}

The configuration contains a static response handler to return a "Hello world!" statement when the URI of a request finishes with /hello.

Add the following file to your local IG configuration as $HOME/.openig/Dockerfile, where $HOME/.openig is the instance directory:
```
FROM ig-image
COPY config/routes/hello.json "$IG_INSTANCE_DIR"/config/routes/hello.json
```
The Dockerfile copies hello.json into the Docker image. The $IG_INSTANCE_DIR environment variable is defined in the IG base image.

Build the Docker image:

$ docker build . -t ig-custom
      
Sending build context to Docker daemon
 Step 1/2 : FROM ig-image
 Step 2/2 : COPY config/routes/hello.json "$IG_INSTANCE_DIR"/config/routes/hello.json
 Successfully tagged ig-custom:latest

Make sure that the Docker image is available:

$ docker image list
REPOSITORY               TAG                IMAGE ID
ig-custom                image_tag          51b...3b7
gcr.io/forgerock-io/ig   image_tag          404...a2b

Run the Docker image on port 8080:
```
$ docker run -p 8080:8080 ig-custom
```
Go to http://localhost:8080/hello. The "Hello world!" statement is displayed.