add command option also to docker job type

Author: ib-steffen

docs/doc.md

@@ -25,6 +25,7 @@ The job type docker is one of the most important jobs. You can use it to run any
         "type": "docker",
         "name": "build",
         "docker_file": "infrabox/build-and-test/Dockerfile",
+        "command": ["echo", "hello world"]
         "resources": { "limits": { "cpu": 1, "memory": 1024 } },
         "build_only": false,
         "build_context": "...",
@@ -46,6 +47,7 @@ The job type docker is one of the most important jobs. You can use it to run any
 |type|true|string||Has to be "docker" to run a single Docker container|
 |name|true|string||Name of the job|
 |docker_file|true|string||Path to the `Dockerfile`|
+|command|false|string||The command in [exec form](https://docs.docker.com/engine/reference/builder/#cmd) to be used when the container is run. Ignored if `build_only=false`|
 |resources|true|[Resource Configuration](#resource-configuration)||Specify the required resources for your job|
 |build_only|true|boolean|true|If set to true the container will only be build but not run. Use it if you only want to build a container and push it to a registry. See here for how to push to a docker registry.|
 |build_context|false|string||Specify the docker build context. If not set the directory containing the `infrabox.json` file will be used.|

src/pyinfrabox/infrabox/__init__.py

@@ -246,7 +246,7 @@ def parse_docker_image(d, path):
 def parse_docker(d, path):
     check_allowed_properties(d, path, ("type", "name", "docker_file", "depends_on", "resources",
                                        "build_only", "environment",
-                                       "build_arguments", "deployments", "timeout", "security_context",
+                                       "build_arguments", "deployments", "timeout", "security_context", "command",
                                        "build_context", "cache", "repository", "cluster", "services", "registries"))
     check_required_properties(d, path, ("type", "name", "docker_file", "resources"))
     check_name(d['name'], path + ".name")
@@ -292,6 +292,9 @@ def parse_docker(d, path):
     if 'registries' in d:
         parse_registries(d['registries'], path + '.registries')
 
+    if 'command' in d:
+        check_string_array(d['command'], path + ".command")
+
 def parse_docker_compose(d, path):
     check_allowed_properties(d, path, ("type", "name", "docker_compose_file", "depends_on",
                                        "environment", "resources", "cache", "timeout", "cluster", "repository"))