viam.services.generic

Submodules

Classes

Generic

Generic service, which represents any type of service that can execute arbitrary commands

Package Contents

class viam.services.generic.Generic(name: str, *, logger: logging.Logger | None = None)[source]

Bases: viam.services.service_base.ServiceBase

Generic service, which represents any type of service that can execute arbitrary commands

This acts as an abstract base class for any drivers representing generic services. This cannot be used on its own. If the __init__() function is overridden, it must call the super().__init__() function.

To create a Generic service (an arbitrary service that can process commands), this Generic service should be subclassed and the do_command function implemented.

Example:

class ComplexService(Generic):

    async def do_command(
        self,
        command: Mapping[str, ValueTypes],
        *,
        timeout: Optional[float] = None,
        **kwargs
    ) -> Mapping[str, ValueTypes]:
        result = {key: False for key in command.keys()}
        for (name, args) in command.items():
            if name == 'set_val':
                self.set_val(*args)
                result[name] = True
            if name == 'get_val':
                result[name] = self.val
            if name == 'complex_command':
                self.complex_command(*args)
                result[name] = True
        return result

    def set_val(self, val: int):
        self.val = val

    def complex_command(self, arg1, arg2, arg3):
        ...

To execute commands, simply call the do_command function with the appropriate parameters.

await service.do_command({'set_val': 10})
service.val  # 10
await service.do_command({'set_val': 5})
service.val  # 5

SUBTYPE: Final: The Subtype of the Resource

classmethod from_robot(robot: viam.robot.client.RobotClient, name: str) → typing_extensions.Self

Get the service named name from the provided robot.

async def connect() -> RobotClient:
    # Replace "<API-KEY>" (including brackets) with your API key and "<API-KEY-ID>" with your API key ID
    options = RobotClient.Options.with_api_key("<API-KEY>", "<API-KEY-ID>")
    # Replace "<MACHINE-URL>" (included brackets) with your machine's connection URL or FQDN
    return await RobotClient.at_address("<MACHINE-URL>", options)

async def main():
    robot = await connect()

    # Can be used with any resource, using the motion service as an example
    motion = MotionClient.from_robot(robot=machine, name="builtin")

    robot.close()

Parameters:

robot (RobotClient) – The robot
name (str) – The name of the service

Returns:

The service, if it exists on the robot

Return type:

Self

abstract do_command(command: Mapping[str, viam.utils.ValueTypes], *, timeout: float | None = None, **kwargs) → Mapping[str, viam.utils.ValueTypes]

Async:

Send/receive arbitrary commands.

service = SERVICE.from_robot(robot=machine, "builtin")  # replace SERVICE with the appropriate class

my_command = {
  "cmnd": "dosomething",
  "someparameter": 52
}

# Can be used with any resource, using the motion service as an example
await service.do_command(command=my_command)

Parameters:: command (Dict[str, ValueTypes]) – The command to execute
Returns:: Result of the executed command
Return type:: Dict[str, ValueTypes]

classmethod get_resource_name(name: str) → viam.proto.common.ResourceName

Get the ResourceName for this Resource with the given name

# Can be used with any resource, using an arm as an example
my_arm_name = Arm.get_resource_name("my_arm")

Parameters:: name (str) – The name of the Resource
Returns:: The ResourceName of this Resource
Return type:: ResourceName

get_operation(kwargs: Mapping[str, Any]) → viam.operations.Operation

Get the Operation associated with the currently running function.

When writing custom resources, you should get the Operation by calling this function and check to see if it’s cancelled. If the Operation is cancelled, then you can perform any necessary (terminating long running tasks, cleaning up connections, etc. ).

Parameters:: kwargs (Mapping[str, Any]) – The kwargs object containing the operation
Returns:: The operation associated with this function
Return type:: viam.operations.Operation

async close()

Safely shut down the resource and prevent further use.

Close must be idempotent. Later configuration may allow a resource to be “open” again. If a resource does not want or need a close function, it is assumed that the resource does not need to return errors when future non-Close methods are called.

await component.close()