[docker] Add container docs and example usage

README.md

@@ -111,16 +111,41 @@ After cloning the project, you can build it from source with this command:
 mvn package
 ```
 
+### Homebrew
+
+To install, run `brew install swagger-codegen`
+
+Here is an example usage:
+```
+swagger-codegen generate -i http://petstore.swagger.io/v2/swagger.json -l ruby -o /tmp/test/
+```
+
 ### Docker
-#### Build and run using docker
+
+#### Development in docker
+
+You can use `run-in-docker.sh` to do all development. This script maps your local repository to `/gen`
+in the docker container. It also maps `~/.m2/repository` to the appropriate container location.
+
+To execute `mvn package`:
 
 ```
 git clone https://github.com/swagger-api/swagger-codegen
 cd swagger-codegen
 ./run-in-docker.sh mvn package
- ```
+```
 
+Build artifacts are now accessible in your working directory.
 
+Once built, `run-in-docker.sh` will act as an executable for swagger-codegen-cli. To generate code, you'll need to output to a directory under `/gen` (e.g. `/gen/out`). For example:
+
+```
+./run-in-docker.sh help # Executes 'help' command for swagger-codegen-cli
+./run-in-docker.sh langs # Executes 'langs' command for swagger-codegen-cli
+./run-in-docker.sh /gen/bin/go-petstore.sh  # Builds the Go client
+./run-in-docker.sh generate -i modules/swagger-codegen/src/test/resources/2_0/petstore.yaml \
+    -l go -o /gen/out/go-petstore -DpackageName=petstore # generates go client, outputs locally to ./out/go-petstore
+```
 
 #### Run Docker in Vagrant
 Prerequisite: install [Vagrant](https://www.vagrantup.com/downloads.html) and [VirtualBox](https://www.virtualbox.org/wiki/Downloads).
@@ -133,17 +158,53 @@ cd /vagrant
 ./run-in-docker.sh mvn package
  ```
 
-#### Public Docker image
+#### Public Pre-built Docker images
 
-https://hub.docker.com/r/swaggerapi/swagger-generator/
+* Swagger Generator: https://hub.docker.com/r/swaggerapi/swagger-generator/
+* Swagger Codegen  : https://hub.docker.com/r/swaggerapi/swagger-codegen/
 
-### Homebrew
-To install, run `brew install swagger-codegen`
+##### Swagger Generator Docker Image
+
+The Swagger Generator image can act as a self-hosted web application and API for generating code. This container can be  incorporated into a CI pipeline, and requires at least two HTTP requests and some docker orchestration to access generated code.
+
+Example usage (note this assumes `jq` is installed for command line processing of JSON):
 
-Here is an example usage:
 ```
-swagger-codegen generate -i http://petstore.swagger.io/v2/swagger.json -l ruby -o /tmp/test/
+# Start container and save the container id
+CID=$(docker run -d swaggerapi/swagger-generator)
+# allow for startup
+sleep 5
+# Get the IP of the running container
+GEN_IP=$(docker inspect --format '{{.NetworkSettings.IPAddress}}'  $CID)
+# Execute an HTTP request and store the download link
+RESULT=$(curl -X POST --header 'Content-Type: application/json' --header 'Accept: application/json' -d '{
+  "swaggerUrl": "http://petstore.swagger.io/v2/swagger.json"
+}' 'http://localhost:8188/api/gen/clients/javascript' | jq '.link' | tr -d '"')
+# Download the generated zip and redirect to a file
+curl $RESULT > result.zip
+# Shutdown the swagger generator image
+docker stop $CID && docker rm $CID
 ```
+
+In the example above, `result.zip` will contain the generated client.
+
+##### Swagger Codegen Docker Image
+
+The Swagger Codegen image acts as a standalone executable. It can be used as an alternative to installing via homebrew, or for developers who are unable to install Java or upgrade the installed version.
+
+To generate code with this image, you'll need to mount a local location as a volume.
+
+Example:
+
+```
+docker run --rm -v ${PWD}:/local swagger-api/swagger-codegen generate \
+    -i http://petstore.swagger.io/v2/swagger.json \
+    -l go \
+    -o /local/out/go
+```
+
+The generated code will be located under `./out/go` in the current directory.
+
 ## Getting Started
 
 To generate a PHP client for http://petstore.swagger.io/v2/swagger.json, please run the following