Documentation
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Overview ¶
Command muniverse-bind uses stdin and stdout to serve an API for controlling muniverse environments. It is intended to be executed by muniverse packages in other programming languages.
The API uses a BSON protocol over stdin and stdout. In this protocol, the front-end sends calls to the back-end and receives responses back. Multiple calls can be running asynchronously.
Call Format ¶
When a call is sent to the back-end, it is encoded as a BSON object with a preceding length field. The length field is a 4-byte little-endian integer indicating the size of the BSON object. Call objects have an "ID" field which is a string used to identify the response to the call. Call objects have a single field besides the "ID" field which stores the arguments of the call. The name of this field is the name of the call.
Response Format ¶
The response to a call is, like a call, encoded as a BSON object with a preceding length field. A response object has an "ID" field matching the "ID" of the call. If a call fails, it has a non-null Error field which is a string error message. Otherwise, the response object may have other fields depending on the type of the return value.
Types of Calls ¶
The SpecForName call looks up an environment by name. The call takes a "Name" string argument. The response has a "Spec" field which is an environment specification object. If the environment was not found, the "Spec" field will be absent.
The NewEnv call creates an environment from an environment specification object. The call takes a "Spec" argument, which is an environment specification object. The response has a "UID" field, which is a string identifier for the new environment instance.
The NewEnvContainer call is like NewEnv, but it uses a custom Docker container. The call and response are the same as NewEnv, except that the call has an extra "Container" argument naming the Docker container.
The NewEnvChrome call is like NewEnv, but it uses a custom Chrome instance and game server. The call and response are the same as NewEnv, except that the call has "Host" and "GameHost" arguments.
The CloseEnv call closes an environment. The call takes a "UID" argument. The response has no fields.
The Reset call resets an environment. The call takes a "UID" argument. The response has no fields.
The Step call takes a step in an environment. It takes three arguments: a "UID" string, a "Seconds" floating point, and an "Events" array. Each event in the "Events" array contains either a "KeyEvent" or "MouseEvent" field. The contents of those fields match chrome.KeyEvent and chrome.MouseEvent. The response has a "StepResult" field which is an object containing a "Reward" and "Done" field.
The Observe call takes an environment screenshot. It takes a "UID" argument. The response has an "Observation" field which is an object containing "Width", "Height", and "RGB" fields. The "Width" and "Height" are integers. The "RGB" field is 24-bit RGB data.
The KeyForCode call looks up the default fields of a key event given its code. It takes a "Code" argument. The response has a "KeyEvent" field with the fields from the chrome.KeyEvent object. If the code was not found, the "KeyEvent" field will be absent.
Source Files