In order to provide environment-specific configurations, we introduced the environments configuration, which allows you to override the default configuration specified on the LCP.json.

There are some specific rules that apply depending on the type of property that you're trying to override. This article will cover these specific use cases. But first, let's take a look at a basic use case of this feature.

Basic Behavior

Let's say we want to block the CI service to be deployed from all environments, except the infra environment.

In this case, we can define deploy: false as the default behavior and add deploy: true only for that specific environment.

{
  "id": "ci",
  "memory": 8192,
  "cpu": 4,
  "deploy": false,
  "environments": {
    "infra": {
      "deploy": true
    }
  }
}

JSON Object Behavior

Now let's imagine we want to allow the CDN to be enabled in all environments, but in the dev environment we want it to be disabled.

In this case, we're dealing with loadBalancer, which is a JSON object. For these types of properties, we adopt a merging behavior. Therefore, you can only specify what changed. That's why we don't need to declare the targetPort once again.

{
  "id": "webserver",
  "memory": 512,
  "cpu": 2,
  "loadBalancer": {
    "targetPort": 80,
    "cdn": true
  },
  "environments": {
    "dev": {
      "loadBalancer": {
        "cdn": false
      }
    }
  }
}

The resulting loadBalancer object would look like this on the dev environment:

"loadBalancer": {
  "targetPort": 80,
  "cdn": false
}

JSON Array Behavior

Finally, let's say we want to have all ports closed, but open only one port externally available in the uat environment.

In this case, we're dealing with ports, which is a JSON array. For these types of properties, we adopt an override behavior. This means that we need to be explicit about what we want to change.

{
  "id": "database",
  "memory": 1024,
  "cpu": 2,
  "ports": [
    {
      "port": 3306,
      "external": false
    },
    {
      "port": 3000,
      "external": false
    }
  ],
  "environments": {
    "uat": {
      "ports": [
        {
          "port": 3306,
          "external": true
        }
      ]
    }
  }
}

The resulting ports array would look like this on the uat environment:

"ports": [
  {
    "port": 3306,
    "external": true
  }
]