Use config.env for parameterization config

Author: aweiteka

README.md

@@ -45,6 +45,7 @@ The following types of data are being considered:
  | authoritative-source-url | The authoritative location in which the image is published|
  | distribution-scope  | Intended scope of distribution for image (see below for possible values)|
  | changelog-url | URL of a page containing release notes for the image|
+ | config       | A namespace for defining the application configuration (see below for possible values)|
 
 3. Possible values of distribution-scope field
 
@@ -55,11 +56,27 @@ The following types of data are being considered:
  | restricted  | Redistribution only with permission|
  | public      | No redistribution limits beyond licenses|
 
-4. Custom labels may be defined by a namespace prefix using reverse DNS notation of a domain controlled by the author. For example, `com.redhat.access`.
+4. Possible values of config field. Application configuration may be defined or hinted using the config label. This allows documentation and tooling to provide parameterization control. Currently, environment variables are the only parameter, with three attributes.
+
+ |Name         | Description |
+ |-------------|-------------|
+ | config.env.KEY             | Default value. Use empty string "" if no default.|
+ | config.env.KEY.description | Description|
+ | config.env.KEY.required    | Required boolean, true or false.|
+
+Example:
+
+```
+LABEL config.env.foo=bar \
+      config.env.foo.description="Lorem ipsum dolor sit amet" \
+      config.env.foo.required=true
+```
+5. Custom labels may be defined by a namespace prefix using reverse DNS notation of a domain controlled by the author. For example, `com.redhat.access`.
 
         LABEL io.openshift.expose-services="8080:http" \
               io.openshift.tags="builder,nodejs,nodejs010"
 
+
 ## Details on Labels
 
 ## `authoritative-source-url`

vendor/redhat/labels.md

@@ -45,10 +45,6 @@ $authoritative-source[:PORT]/PRODUCT[$PRODUCTGEN][--$PLATFORMDIFFERENTIATOR]/REP
 | io.k8s.display-name | no | Name of the container displayed in Kubernetes |
 | io.openshift.expose-services | no | port:service pairs separated with comma, e.g. `"8080:http,8443:https"` |
 | io.openshift.tags | no | tags used by searching engine, e.g. `"builder,php,php56,rh-php56"` |
-| io.openshift.env-KEY | no | Required environment variable. Creates parameter named "KEY". If no value is provided user input required. |
-| io.openshift.podhook.pre | no | Pre exec pod-based lifecycle hook command. See [documentation](https://docs.openshift.org/latest/dev_guide/deployments.html#pod-based-lifecycle-hook) |
-| io.openshift.podhook.post | no | Post exec pod-based lifecycle hook command. See [documentation](https://docs.openshift.org/latest/dev_guide/deployments.html#pod-based-lifecycle-hook) |
-
 
 ### Examples
 
@@ -116,3 +112,5 @@ $authoritative-source[:PORT]/PRODUCT[$PRODUCTGEN][--$PLATFORMDIFFERENTIATOR]/REP
                     "io.openshift.expose-services="8080:http",
                     "io.openshift.tags="builder,php,php56,rh-php56"
                 },
+
+