Golem Python API Reference

Golem

class yapapi.Golem(*, budget, strategy=None, subnet_tag=None, driver=None, payment_driver=None, network=None, payment_network=None, event_consumer=None, stream_output=False, app_key=None)

The main entrypoint of Golem's high-level API.

Its principal role is providing an interface to run the requestor’s payload using one of two modes of operation - executing tasks and running services.

The first one, available through execute_tasks(), instructs Golem to take a sequence of tasks that the user wishes to compute on Golem and distributes those among the providers.

The second one, invoked with run_service(), makes Golem spawn a certain number of instances of a service based on a single service specification (a specialized implementation inheriting from Service).

While the two modes are not necessarily completely disjoint - in that we can create a service that exists to process a certain number of computations and, similarly, we can use the task model to run some service - the main difference lies in the lifetime of such a job.

Whereas a task-based job exists for the purpose of computing the specific sequence of tasks and is done once the whole sequence has been processed, the service-based job is created for a potentially indefinite period and the services spawned within it are kept alive for as long as they’re needed.

Additionally, the service interface provides a way to easily define handlers for certain, discrete phases of a lifetime of each service instance - startup, running and shutdown.

Internally, Golem’s job includes running the engine which takes care of first finding the providers interested in the jobs the requestors want to execute, then negotiating agreements with them and facilitating the execution of those jobs and lastly, processing payments. For this reason, it’s usually good to have just one instance of Golem operative at any given time.

__init__(*, budget, strategy=None, subnet_tag=None, driver=None, payment_driver=None, network=None, payment_network=None, event_consumer=None, stream_output=False, app_key=None)

Initialize Golem engine.

Parameters

budget (Union[float, Decimal]) – maximum budget for payments
strategy (Optional[BaseMarketStrategy]) – market strategy used to select providers from the market (e.g. yapapi.strategy.LeastExpensiveLinearPayuMS or yapapi.strategy.DummyMS)
subnet_tag (Optional[str]) – use only providers in the subnet with the subnet_tag name. Uses YAGNA_SUBNET environment variable, defaults to None
driver (Optional[str]) – deprecated, please use payment_driver instead
payment_driver (Optional[str]) – name of the payment driver to use. Uses YAGNA_PAYMENT_DRIVER environment variable, defaults to erc20. Only payment platforms with the specified driver will be used
network (Optional[str]) – deprecated, please use payment_network instead
payment_network (Optional[str]) – name of the network to use. Uses YAGNA_NETWORK environment variable, defaults to rinkeby. Only payment platforms with the specified network will be used
event_consumer (Optional[Callable[[Event], None]]) – a callable that processes events related to the computation; by default it is a function that logs all events
stream_output (bool) – stream computation output from providers
app_key (Optional[str]) – optional Yagna application key. If not provided, the default is to get the value from YAGNA_APPKEY environment variable

add_event_consumer(event_consumer, event_classes_or_names=(<class 'yapapi.events.Event'>, ))

Initialize another event_consumer, working just like the event_consumer passed to Golem.__init__()

Parameters

event_consumer (Callable[[Event], None]) – A callable that will be executed on every event.
event_classes_or_names (Iterable[Union[Type[Event], str]]) – An iterable defining classes of events that should be passed to this event_consumer. Both classes and class names are accepted (in the latter case classes must be available in the yapapi.events namespace). If this argument is omitted, all events inheriting from yapapi.events.Event (i.e. all currently implemented events) will be passed to the event_consumer.

Example usages:

def event_consumer(event: "yapapi.events.Event"):
    print(f"Got an event! {type(event).__name__}")

golem.add_event_consumer(event_consumer)

def event_consumer(event: "yapapi.events.AgreementConfirmed"):
    provider_name = event.agreement.details.provider_node_info.name
    print(f"We're trading with {provider_name}! Nice!")

golem.add_event_consumer(event_consumer, ["AgreementConfirmed"])

async start()

Start the Golem engine in non-contextmanager mode.

The default way of using Golem:

async with Golem(...) as golem:
    # ... work with golem

Is roughly equivalent to:

golem = Golem(...)
try:
    await golem.start()
    # ... work with golem
finally:
    await golem.stop()

A repeated call to Golem.start():

If Golem is already starting, or started and wasn’t stopped - will be ignored (and harmless)
If Golem was stopped - will initialize a new engine that knows nothing about the previous operations

Return type: None

async stop()

Stop the Golem engine after it was started in non-contextmanager mode.

Details: Golem.start()

Return type: None

async execute_tasks(worker, data, payload, max_workers=None, timeout=None, job_id=None, implicit_init=True)

Submit a sequence of tasks to be executed on providers.

Internally, this method creates an instance of yapapi.executor.Executor and calls its submit() method with given worker function and sequence of tasks.

Parameters

worker (Callable[[WorkContext, AsyncIterator[Task[TypeVar(D), TypeVar(R)]]], AsyncGenerator[Script, Awaitable[List[CommandEvent]]]]) – an async generator that takes a WorkContext object and a sequence of tasks, and generates as sequence of scripts to be executed on providers in order to compute given tasks
data (Union[AsyncIterator[Task[TypeVar(D), TypeVar(R)]], Iterable[Task[TypeVar(D), TypeVar(R)]]]) – an iterable or an async generator of Task objects to be computed on providers
payload (Payload) – specification of the payload that needs to be deployed on providers (for example, a VM runtime package) in order to compute the tasks, passed to the created Executor instance
max_workers (Optional[int]) – maximum number of concurrent workers, passed to the Executor instance
timeout (Optional[timedelta]) – timeout for computing all tasks, passed to the Executor instance
job_id (Optional[str]) – an optional string to identify the job created by this method. Passed as the value of the id parameter to yapapi.engine.Job.
implicit_init (bool) – True -> deploy() and start() will be called internally by the Executor. False -> those calls must be in the worker function

Return type

AsyncIterator[Task[TypeVar(D), TypeVar(R)]]

Returns

an async iterator that yields completed Task objects

example usage:

async def worker(context: WorkContext, tasks: AsyncIterable[Task]):
    async for task in tasks:
        context.run("/bin/sh", "-c", "date")

        future_results = yield context.commit()
        results = await future_results
        task.accept_result(result=results[-1])

package = await vm.repo(
    image_hash="d646d7b93083d817846c2ae5c62c72ca0507782385a2e29291a3d376",
)

async with Golem(budget=1.0, subnet_tag="devnet-beta") as golem:
    async for completed in golem.execute_tasks(worker, [Task(data=None)], payload=package):
        print(completed.result.stdout)

async run_service(service_class, num_instances=None, instance_params=None, payload=None, expiration=None, respawn_unstarted_instances=True, network=None, network_addresses=None)

Run a number of instances of a service represented by a given Service subclass.

Parameters

service_class (Type[TypeVar(ServiceType, bound= Service)]) – a subclass of Service that represents the service to be run
num_instances (Optional[int]) – optional number of service instances to run. Defaults to a single instance, unless instance_params is given, in which case, the Cluster will be created with as many instances as there are elements in the instance_params iterable. if num_instances is set to < 1, the Cluster will still be created but no instances will be spawned within it.
instance_params (Optional[Iterable[Dict]]) – optional list of dictionaries of keyword arguments that will be passed to consecutive, spawned instances. The number of elements in the iterable determines the number of instances spawned, unless num_instances is given, in which case the latter takes precedence. In other words, if both num_instances and instance_params are provided, the Cluster will be created with the number of instances determined by num_instances and if there are too few elements in the instance_params iterable, it will results in an error.
payload (Optional[Payload]) – optional runtime definition for the service; if not provided, the payload specified by the get_payload() method of service_class is used
expiration (Optional[datetime]) – optional expiration datetime for the service
respawn_unstarted_instances – if an instance fails in the starting state, should the returned Cluster try to spawn another instance
network (Optional[Network]) – optional Network, representing a VPN to attach this Cluster’s instances to
network_addresses (Optional[List[str]]) – optional list of addresses to assign to consecutive spawned instances. If there are too few addresses given in the network_addresses iterable to satisfy all spawned instances, the rest (or all when the list is empty or not provided at all) of the addresses will be assigned automatically. Requires the network argument to be provided at the same time.

example usage:

DATE_OUTPUT_PATH = "/golem/work/date.txt"
REFRESH_INTERVAL_SEC = 5


class DateService(Service):
    @staticmethod
    async def get_payload():
        return await vm.repo(
            image_hash="d646d7b93083d817846c2ae5c62c72ca0507782385a2e29291a3d376",
        )

    async def start(self):
        async for script in super().start():
            yield script

        # every `DATE_POLL_INTERVAL` write output of `date` to `DATE_OUTPUT_PATH`
        script = self._ctx.new_script()
        script.run(
            "/bin/sh",
            "-c",
            f"while true; do date > {DATE_OUTPUT_PATH}; sleep {REFRESH_INTERVAL_SEC}; done &",
        )
        yield script

    async def run(self):
        while True:
            await asyncio.sleep(REFRESH_INTERVAL_SEC)
            script = self._ctx.new_script()
            future_result = script.run(
                "/bin/sh",
                "-c",
                f"cat {DATE_OUTPUT_PATH}",
            )

            yield script

            result = (await future_result).stdout
            print(result.strip() if result else "")


async def main():
    async with Golem(budget=1.0, subnet_tag="devnet-beta") as golem:
        cluster = await golem.run_service(DateService, num_instances=1)
        start_time = datetime.now()

        while datetime.now() < start_time + timedelta(minutes=1):
            for num, instance in enumerate(cluster.instances):
                print(f"Instance {num} is {instance.state.value} on {instance.provider_name}")
            await asyncio.sleep(REFRESH_INTERVAL_SEC)

Return type: Cluster[TypeVar(ServiceType, bound= Service)]

async create_network(ip, owner_ip=None, mask=None, gateway=None)

Create a VPN inside Golem network.

Requires yagna >= 0.8

Parameters

ip (str) – the IP address of the network. May contain netmask, e.g. “192.168.0.0/24”
owner_ip (Optional[str]) – the desired IP address of the requestor node within the newly-created Network
mask (Optional[str]) – Optional netmask (only if not provided within the ip argument)
gateway (Optional[str]) – Optional gateway address for the network

Return type

Network

Task API

Task

class yapapi.Task(data)

One computation unit.

Represents one computation unit that will be run on the provider (e.g. rendering of one frame of an animation).

__init__(data)

Create a new Task object.

Parameters: data (TypeVar(TaskData)) – contains information needed to prepare command list for the provider

property running_time: Optional[datetime.timedelta]

Return the running time of the task (if in progress) or time it took to complete it.

Return type: Optional[timedelta]

accept_result(result=None)

Accept the result of this task.

Must be called when the result is correct to mark this task as completed.

Parameters: result (Optional[TypeVar(TaskResult)]) – task computation result (optional)
Return type: None

reject_result(reason=None, retry=False)

Reject the result of this task.

Must be called when the result is not correct to indicate that the task should be retried.

Parameters: reason (Optional[str]) – task rejection description (optional)
Return type: None

Service API

Service

class yapapi.services.Service

Base class for service specifications.

To be extended by application developers to define their own, specialized Service specifications.

property id: str

Return the unique id of this service instance.

Return type: str

property provider_name: Optional[str]

Return the name of the provider that runs this service instance.

Return type: Optional[str]

property network: Optional[yapapi.network.Network]

Return the Network to which this instance belongs (if any)

Return type: Optional[Network]

property network_node: Optional[yapapi.network.Node]

Return the network Node record associated with this instance.

Return type: Optional[Node]

async send_message(message=None): Send a control message to this instance.

send_message_nowait(message=None)

Send a control message to this instance without blocking.

May raise asyncio.QueueFull if the channel for sending control messages is full.

async receive_message()

Wait for a control message sent to this instance.

Return type: ServiceSignal

receive_message_nowait()

Retrieve a control message sent to this instance.

Return None if no message is available.

Return type: Optional[ServiceSignal]

async static get_payload()

Return the payload (runtime) definition for this service.

To be overridden by the author of a specific Service class.

If get_payload() is not implemented, the payload will need to be provided in the run_service() call.

Return type: Optional[Payload]

async start()

Implement the handler for the starting state of the service.

To be overridden by the author of a specific Service class.

Should perform the minimum set of operations after which the instance of a service can be treated as “started”, or, in other words, ready to receive service requests. It’s up to the developer of the specific Service class to decide what exact operations constitute a service startup. In the most common scenario deploy() and start() are required, check the Default implementation section for more details.

As a handler implementing the work generator pattern, it’s expected to be a generator that yields Script (generated using the service’s instance of the WorkContext - self._ctx) that are then dispatched to the activity by the engine.

Results of those batches can then be retrieved by awaiting the values captured from yield statements.

A clean exit from a handler function triggers the engine to transition the state of the instance to the next stage in service’s lifecycle - in this case, to running.

On the other hand, any unhandled exception will cause the instance to be either retried on another provider node, if the Cluster’s respawn_unstarted_instances argument is set to True in run_service(), which is also the default behavior, or altogether terminated, if respawn_unstarted_instances is set to False.

Example:

async def start(self):
    s = self._ctx.new_script()
    # deploy the exe-unit
    s.deploy(**self.get_deploy_args())
    # start the exe-unit's container
    s.start()
    # start some service process within the container
    s.run("/golem/run/service_ctl", "--start")
    # send the batch to the provider
    yield s

### Default implementation

The default implementation assumes that, in order to accept commands, the runtime needs to be first deployed using the deploy() command, which is analogous to creation of a container corresponding with the desired payload, and then started using the start() command, actually launching the process that runs the aforementioned container.

Additionally, it also assumes that the exe-unit doesn’t need any additional parameters in its start() call (e.g. for the VM runtime, all the required parameters are already passed as part of the agreement between the requestor and the provider), and parameters passed to deploy() are returned by Service.get_deploy_args() method.

Therefore, this default implementation performs the minimum required for a VM payload to start responding to run commands. If your service requires any additional operations - you’ll need to override this method (possibly first yielding from the parent - super().start() - generator) to add appropriate preparatory steps.

In case of runtimes other than VM, deploy and/or start might be optional or altogether disallowed, or they may take some parameters. It is up to the author of the specific Service implementation that uses such a payload to adjust this method accordingly based on the requirements for the given runtime/exe-unit type.

Return type: AsyncGenerator[Script, Awaitable[List[CommandEvent]]]

async run()

Implement the handler for the running state of the service.

To be overridden by the author of a specific Service class.

Should contain any operations needed to ensure continuous operation of a service.

As a handler implementing the work generator pattern, it’s expected to be a generator that yields Script (generated using the service’s instance of the WorkContext - self._ctx) that are then dispatched to the activity by the engine.

Results of those batches can then be retrieved by awaiting the values captured from yield statements.

A clean exit from a handler function triggers the engine to transition the state of the instance to the next stage in service’s lifecycle - in this case, to stopping.

Any unhandled exception will cause the instance to be terminated.

Example:

async def run(self):
    while True:
        script = self._ctx.new_script()
        stats_results = script.run(self.SIMPLE_SERVICE, "--stats")
        yield script
        stats = (await stats_results).stdout.strip()
        print(f"stats: {stats}")

Default implementation

Because the nature of the operations required during the “running” state depends directly on the specifics of a given Service and because it’s entirely plausible for a service not to require any direct interaction with the exe-unit (runtime) from the requestor’s end after the service has been started, the default is to just wait indefinitely without producing any batches.

Return type: AsyncGenerator[Script, Awaitable[List[CommandEvent]]]

async shutdown()

Implement the handler for the stopping state of the service.

To be overridden by the author of a specific Service class.

Should contain any operations that the requestor needs to ensure the instance is correctly and gracefully shut-down - e.g. that its final state is retrieved.

As a handler implementing the work generator pattern, it’s expected to be a generator that yields Script (generated using the service’s instance of the WorkContext - self._ctx) that are then dispatched to the activity by the engine.

Results of those batches can then be retrieved by awaiting the values captured from yield statements.

Finishing the execution of this handler will trigger termination of this instance.

This handler will only be called if the activity running the service is still available. If the activity has already been deemed terminated or if the connection with the provider has been lost, the service will transition to the terminated state and the shutdown handler won’t be run.

Example:

async def shutdown(self):
    self._ctx.run("/golem/run/dump_state")
    self._ctx.download_file("/golem/output/state", "/some/local/path/state")
    self._ctx.terminate()
    yield self._ctx.commit()

Default implementation

By default, the activity is just sent a terminate command. Whether it’s absolutely required or not, again, depends on the implementation of the given runtime.

Return type: AsyncGenerator[Script, Awaitable[List[CommandEvent]]]

async reset()

Reset the service to the initial state.

This method is called internally when the service is restarted in yapapi.services.ServiceRunner, so it is not necessary for services that are never restarted (note that run_service() by default restarts services that didn’t start properly).

Handlers of a restarted service are called more then once - all of the cleanup necessary between calls should be implemented here. E.g. if we initialize a counter in Service.__init__() and increment it in Service.start(), we might want to reset it here to the initial value.

Target implementation (0.10.0 and up) will raise NotImplementedError. Current implementation only warns about this future change.

Return type: None

property is_available: Return True iff this instance is available (that is, starting, running or stopping).

property state: Return the current state of this instance.

Cluster

class yapapi.services.Cluster(engine, service_class, payload, expiration=None, respawn_unstarted_instances=True, network=None)

Golem’s sub-engine used to spawn and control instances of a single Service.

async terminate(): Signal the whole Cluster and the underlying ServiceRunner to stop.

stop(): Stop all services in this Cluster

property expiration: datetime.datetime

Return the expiration datetime for agreements related to services in this Cluster.

Return type: datetime

property payload: yapapi.payload.Payload

Return the service runtime definition for this Cluster.

Return type: Payload

property service_class: Type[yapapi.services.service.ServiceType]

Return the class instantiated by all service instances in this Cluster.

Return type: Type[TypeVar(ServiceType, bound= Service)]

property network: Optional[yapapi.network.Network]

Return the Network record associated with the VPN used by this Cluster.

Return type: Optional[Network]

property instances: List[yapapi.services.service.ServiceType]

Return the list of service instances in this Cluster.

Return type: List[TypeVar(ServiceType, bound= Service)]

stop_instance(service): Stop the specific Service instance belonging to this Cluster.

spawn_instances(num_instances=None, instance_params=None, network_addresses=None)

Spawn new instances within this Cluster.

Parameters

num_instances (Optional[int]) – optional number of service instances to run. Defaults to a single instance, unless instance_params is given, in which case, the Cluster will spawn as many instances as there are elements in the instance_params iterable. if num_instances is not None and < 1, the method will immediately return and log a warning.
instance_params (Optional[Iterable[Dict]]) – optional list of dictionaries of keyword arguments that will be passed to consecutive, spawned instances. The number of elements in the iterable determines the number of instances spawned, unless num_instances is given, in which case the latter takes precedence. In other words, if both num_instances and instance_params are provided, the number of instances spawned will be equal to num_instances and if there are too few elements in the instance_params iterable, it will results in an error.
network_addresses (Optional[List[str]]) – optional list of network addresses in case the Cluster is attached to VPN. If the list is not provided (or if the number of elements is less than the number of spawned instances), any instances for which the addresses have not been given, will be assigned an address automatically.

Return type

None

ServiceState

class yapapi.services.ServiceState(model=None, state_field='state', start_value=None): State machine describing the state and lifecycle of a Service instance.

Network API

Network

class yapapi.network.Network(net_api, ip, owner_id, owner_ip=None, mask=None, gateway=None)

Describes a VPN created between the requestor and the provider nodes within Golem Network.

async classmethod create(net_api, ip, owner_id, owner_ip=None, mask=None, gateway=None)

Create a new VPN.

Parameters

net_api (Net) – the mid-level binding used directly to perform calls to the REST API.
ip (str) – the IP address of the network. May contain netmask, e.g. “192.168.0.0/24”
owner_id (str) – the node ID of the owner of this VPN (the requestor)
owner_ip (Optional[str]) – the desired IP address of the requestor node within the newly-created network
mask (Optional[str]) – Optional netmask (only if not provided within the ip argument)
gateway (Optional[str]) – Optional gateway address for the network

Return type

Network

property owner_ip: str

The IP address of the requestor node within the network.

Return type: str

property network_address: str

The network address of this network, without a netmask.

Return type: str

property netmask: str

The netmask of this network.

Return type: str

property gateway: Optional[str]

The gateway address within this network, if provided.

Return type: Optional[str]

property nodes_dict: Dict[str, str]

Mapping between the IP addresses and Node IDs of the nodes within this network.

Return type: Dict[str, str]

property network_id: str

The automatically-generated, unique ID of this VPN.

Return type: str

async add_owner_address(ip)

Assign the given IP address to the requestor in the network.

Parameters: ip (str) – the IP address to assign to the requestor node.

async add_node(node_id, ip=None)

Add a new node to the network.

Parameters

node_id (str) – Node ID within the Golem network of this VPN node.
ip (Optional[str]) – IP address to assign to this node.

Return type

Node

Node

class yapapi.network.Node(network, node_id, ip)

Describes a node in a VPN, mapping a Golem node id to an IP address.

network: yapapi.network.Network: The Network (the specific VPN) this node is part of.

node_id: str: Golem id of the node.

ip: str: IP address of this node in this particular VPN.

get_deploy_args()

Generate a dictionary of arguments that are required for the appropriate Deploy command of an exescript in order to pass the network configuration to the runtime on the provider’s end.

Return type: Dict

Exceptions

class yapapi.network.NetworkError: Exception raised by Network when an operation is not possible

Payload definition

Payload

class yapapi.payload.Payload(**kwargs)

Base class for descriptions of the payload required by the requestor.

example usage:

import asyncio

from dataclasses import dataclass
from yapapi.props.builder import DemandBuilder
from yapapi.props.base import prop, constraint
from yapapi.props import inf

from yapapi.payload import Payload

CUSTOM_RUNTIME_NAME = "my-runtime"
CUSTOM_PROPERTY = "golem.srv.app.myprop"


@dataclass
class MyPayload(Payload):
    myprop: str = prop(CUSTOM_PROPERTY, default="myvalue")
    runtime: str = constraint(inf.INF_RUNTIME_NAME, default=CUSTOM_RUNTIME_NAME)
    min_mem_gib: float = constraint(inf.INF_MEM, operator=">=", default=16)
    min_storage_gib: float = constraint(inf.INF_STORAGE, operator=">=", default=1024)


async def main():
    builder = DemandBuilder()
    payload = MyPayload(myprop="othervalue", min_mem_gib=32)
    await builder.decorate(payload)
    print(builder)

asyncio.run(main())

output:

{'properties': {'golem.srv.app.myprop': 'othervalue'}, 'constraints': ['(&(golem.runtime.name=my-runtime)
(golem.inf.mem.gib>=32)
(golem.inf.storage.gib>=1024))']}

Package

class yapapi.payload.package.Package: Description of a task package (e.g. a VM image) deployed on the provider nodes

vm.repo

async yapapi.payload.vm.repo(*, image_hash, image_url=None, min_mem_gib=0.5, min_storage_gib=2.0, min_cpu_threads=1, capabilities=None)

Build a reference to application package.

Parameters

image_hash (str) – hash of the package’s image
image_url (Optional[str]) – URL of the package’s image
min_mem_gib (float) – minimal memory required to execute application code
min_storage_gib (float) – minimal disk storage to execute tasks
min_cpu_threads (int) – minimal available logical CPU cores
capabilities (Optional[List[Literal[‘vpn’]]]) – an optional list of required vm capabilities

Return type

Package

Returns

the payload definition for the given VM image

example usage:

package = await vm.repo(
    # if we provide only the image hash, the image will be
    # automatically pulled from Golem's image repository
    image_hash="d646d7b93083d817846c2ae5c62c72ca0507782385a2e29291a3d376",
)

example usage with an explicit GVMI image URL (useful to host images outside the Golem repository):

package = await vm.repo(
    # we still need to provide the image's hash because
    # the image's integrity is validated by the runtime on the provider node
    #
    # the hash can be calculated by running `sha3sum -a 224 <image_filename.gvmi>`
    #
    image_hash="d646d7b93083d817846c2ae5c62c72ca0507782385a2e29291a3d376",

    # the URL can point to any publicly-available location on the web
    image_url="http://girepo.dev.golem.network:8000/docker-golem-hello-world-latest-779758b432.gvmi",
)

example usage with additional constraints:

package = await vm.repo(
    image_hash="9a3b5d67b0b27746283cb5f287c13eab1beaa12d92a9f536b747c7ae",
    # only run on provider nodes that have more than 0.5gb of RAM available
    min_mem_gib=0.5,
    # only run on provider nodes that have more than 2gb of storage space available
    min_storage_gib=2.0,
    # only run on provider nodes which a certain number of CPU threads available
    min_cpu_threads=min_cpu_threads,
)

Execution control

WorkContext

class yapapi.WorkContext(activity, agreement, storage, emitter)

Provider node’s work context.

Used to schedule commands to be sent to the provider and enable other interactions between the requestor agent’s client code and the activity on provider’s end.

property id: str

Unique identifier for this work context.

Return type: str

property provider_name: Optional[str]

Return the name of the provider associated with this work context.

Return type: Optional[str]

property provider_id: str

Return the id of the provider associated with this work context.

Return type: str

new_script(timeout=None, wait_for_results=True)

Create an instance of Script attached to this WorkContext instance.

This is equivalent to calling Script(work_context). This method is intended to provide a direct link between the two object instances.

Return type: Script

async get_raw_usage()

Get the raw usage vector for the activity bound to this work context.

The value comes directly from the low level API and is not interpreted in any way.

Return type: ActivityUsage

async get_usage()

Get the current usage for the activity bound to this work context.

Return type: ActivityUsage

async get_raw_state()

Get the state activity bound to this work context.

The value comes directly from the low level API and is not interpreted in any way.

Return type: ActivityState

async get_cost()

Get the accumulated cost of the activity based on the reported usage.

Return type: Optional[float]

Script

class yapapi.script.Script(context, timeout=None, wait_for_results=True)

Represents a series of commands to be executed on a provider node.

New commands are added to the script either through its add() method or by calling one of the convenience methods provided (for example: run() or upload_json()). Adding a new command does not result in it being immediately executed. Once ready, a Script instance is meant to be yielded from a worker function (work generator pattern). Commands will be run in the order in which they were added to the script.

__init__(context, timeout=None, wait_for_results=True)

Initialize a Script

Parameters

context (WorkContext) – A yapapi.WorkContext that will be used to evaluate the script (i.e. to send commands to the provider)
timeout (Optional[timedelta]) – Time after which this script’s execution should be forcefully interrupted. The default value is None which means there’s no timeout set.
wait_for_results (bool) – Whether this script’s execution should block until its results are available. The default value is True.

property id: int

Return the ID of this Script instance.

IDs are provided by a global iterator and therefore are guaranteed to be unique during the program’s execution.

Return type: int

add(cmd)

Add a yapapi.script.command.Command to the Script

Return type: Awaitable[CommandExecuted]

deploy(**kwargs)

Schedule a Deploy command on the provider.

Return type: Awaitable[CommandExecuted]

start(*args)

Schedule a Start command on the provider.

Return type: Awaitable[CommandExecuted]

terminate()

Schedule a Terminate command on the provider.

Return type: Awaitable[CommandExecuted]

run(cmd, *args, env=None, stderr=None, stdout=None)

Schedule running a shell command on the provider.

Parameters

cmd (str) – command to run on the provider, e.g. /my/dir/run.sh
args (str) – command arguments, e.g. “input1.txt”, “output1.txt”
env (Optional[Dict[str, str]]) – optional dictionary with environment variables
stderr (Optional[CaptureContext]) – capture context to use for stderr
stdout (Optional[CaptureContext]) – capture context to use for stdout

Return type

Awaitable[CommandExecuted]

download_bytes(src_path, on_download, limit=1048576)

Schedule downloading a remote file from the provider as bytes.

Parameters

src_path (str) – remote (provider) source path
on_download (Callable[[bytes], Awaitable]) – the callable to run on the received data
limit (int) – limit of bytes to be downloaded (expected size)

Return type

Awaitable[CommandExecuted]

download_file(src_path, dst_path)

Schedule downloading a remote file from the provider.

Parameters

src_path (str) – remote (provider) source path
dst_path (str) – local (requestor) destination path

Return type

Awaitable[CommandExecuted]

download_json(src_path, on_download, limit=1048576)

Schedule downloading a remote file from the provider as JSON.

Parameters

src_path (str) – remote (provider) source path
on_download (Callable[[Any], Awaitable]) – the callable to run on the received data
limit (int) – limit of bytes to be downloaded (expected size)

Return type

Awaitable[CommandExecuted]

upload_bytes(data, dst_path)

Schedule sending bytes data to the provider.

Parameters

data (bytes) – bytes to send
dst_path (str) – remote (provider) destination path

Return type

Awaitable[CommandExecuted]

upload_file(src_path, dst_path)

Schedule sending a file to the provider.

Parameters

src_path (str) – local (requestor) source path
dst_path (str) – remote (provider) destination path

Return type

Awaitable[CommandExecuted]

upload_json(data, dst_path)

Schedule sending JSON data to the provider.

Parameters

data (dict) – dictionary representing JSON data to send
dst_path (str) – remote (provider) destination path

Return type

Awaitable[CommandExecuted]

Market strategies

class yapapi.strategy.MarketStrategy

Abstract market strategy.

async decorate_demand(demand)

Optionally add relevant constraints to a Demand.

Return type: None

abstract async score_offer(offer)

Score offer. Better offers should get higher scores.

Return type: float

class yapapi.strategy.DummyMS(max_fixed_price=Decimal('0.05'), max_price_for=mappingproxy({}), activity=None)

A default market strategy implementation.

Its score_offer() method returns SCORE_NEUTRAL for every offer with prices that do not exceed maximum prices specified for each counter. For other offers, returns SCORE_REJECTED.

class yapapi.strategy.LeastExpensiveLinearPayuMS(expected_time_secs=60, max_fixed_price=Decimal('Infinity'), max_price_for=mappingproxy({})): A strategy that scores offers according to cost for given computation time.

class yapapi.strategy.DecreaseScoreForUnconfirmedAgreement(base_strategy, factor): A market strategy that modifies a base strategy based on history of agreements.

Events

Objects representing events in a Golem computation.

Everytime something important happens, an event is emitted. Emitted events are passed to all current event consumers, set either in yapapi.Golem.__init__() or via yapapi.Golem.add_event_consumer().

Events are considered a semi-experimental feature:

The backward compatibility of subsequent future updates is not guaranteed, the interface might change between major releases without prior deprecation.
Some parts are not documented and should not be considered a public interface.

Every event is described by a set of attributes that can be divided into three groups:

Attributes common to all events, documented on yapapi.events.Event.
Internal parts of yapapi that define the context of the event (details in the next section).
Additional event-specific information, e.g. the reason of the agreement termination for the AgreementTerminated event, described along the particular event classes.

Events should be consumed in a strict read_only mode: event objects are shared between all event consumers, and their attributes are used internally by the Golem engine, so any modification may have unexpected side effects.

Attributes shared by various events

Name	Value	Description
job	`yapapi.engine.Job`	The highest-level unit of a Golem computation, corresponding to a single call to `yapapi.Golem.execute_tasks()` or `yapapi.Golem.run_service()`
subscription	`yapapi.rest.market.Subscription`	Object responsible for gathering offers from the market
proposal	`yapapi.rest.market.OfferProposal`	A single offer from the market
agreement	`yapapi.rest.market.Agreement`	An agreement between provider and requestor (not necessarly confirmed)
activity	`yapapi.rest.activity.Activity`	Object corresponding to a provider-side activity within an agreement
script	`yapapi.script.Script`	[Class documentation available]
command	`yapapi.script.command.Command`	A single command to be executed within a Script
task	`yapapi.executor.task.Task`	[Class documentation available]
service	`yapapi.services.Service`	[Class documentation available]
debit_note	`yapapi.rest.payment.DebitNote`	A single debit note sent by the provider
invoice	`yapapi.rest.payment.Invoice`	A final invoice sent by the provider

Events inheritance tree

Only leaf events are ever emitted, other events (named *Event) are abstract classes
Every abstract class has one more yapapi object attached then the parent, e.g.
- JobEvent is an Event that happened in the context of a particular job
- AgreementEvent is a JobEvent that happened in the context of a particular agreement

Event
    JobEvent
        SubscriptionFailed
        SubscriptionEvent
            SubscriptionCreated
            CollectFailed
        ProposalEvent
            ProposalReceived
            ProposalRejected
            ProposalResponded
            ProposalConfirmed
            ProposalFailed
        NoProposalsConfirmed
        JobStarted
        JobFinished
        AgreementEvent
            AgreementCreated
            AgreementConfirmed
            AgreementRejected
            AgreementTerminated
            ActivityCreateFailed
            WorkerStarted
            ActivityEvent
                ActivityCreated
                TaskEvent
                    TaskStarted
                    TaskFinished
                    TaskAccepted
                    TaskRejected
                ServiceEvent
                    ServiceStarted
                    ServiceFinished
                ScriptEvent
                    ScriptSent
                    CommandEvent
                        CommandStarted
                        CommandStdOut
                        CommandStdErr
                        CommandExecuted
                        DownloadStarted
                        DownloadFinished
                    GettingResults
                    ScriptFinished
                WorkerFinished
            InvoiceEvent
                InvoiceReceived
                InvoiceAccepted
            DebitNoteEvent
                DebitNoteReceived
                DebitNoteAccepted
            PaymentPrepared
            PaymentQueued
            PaymentFailed
    ExecutionInterrupted
    ShutdownFinished

List of event classes

class yapapi.events.Event(*, exc_info=None)

An abstract base class for all types of events.

exc_info: Optional[Tuple[Type[BaseException], BaseException, Optional[types.TracebackType]]]: Tuple containing exception info as returned by sys.exc_info(), if applicable.

timestamp: datetime.datetime: Event creation time

property exception: Optional[BaseException]

Exception associated with this event or None

Return type: Optional[BaseException]

class yapapi.events.JobEvent(job, *, exc_info=None)

class yapapi.events.SubscriptionEvent(job, subscription, *, exc_info=None)

class yapapi.events.ProposalEvent(job, proposal, *, exc_info=None)

class yapapi.events.AgreementEvent(job, agreement, *, exc_info=None)

class yapapi.events.ActivityEvent(job, agreement, activity, *, exc_info=None)

class yapapi.events.TaskEvent(job, agreement, activity, task, *, exc_info=None)

class yapapi.events.ServiceEvent(job, agreement, activity, service, *, exc_info=None)

class yapapi.events.ScriptEvent(job, agreement, activity, script, *, exc_info=None)

class yapapi.events.CommandEvent(job, agreement, activity, script, command, *, exc_info=None)

class yapapi.events.InvoiceEvent(job, agreement, invoice, *, exc_info=None)

class yapapi.events.DebitNoteEvent(job, agreement, debit_note, *, exc_info=None)

class yapapi.events.JobStarted(job, *, exc_info=None)

class yapapi.events.JobFinished(job, *, exc_info=None): job is done, succeded if exception is None failed otherwise.

class yapapi.events.SubscriptionCreated(job, subscription, *, exc_info=None)

class yapapi.events.SubscriptionFailed(job, reason, *, exc_info=None)

class yapapi.events.CollectFailed(job, subscription, reason, *, exc_info=None)

class yapapi.events.ProposalReceived(job, proposal, *, exc_info=None)

class yapapi.events.ProposalRejected(job, proposal, reason=None, *, exc_info=None): We decided to reject provider’s proposal because of a reason

class yapapi.events.ProposalResponded(job, proposal, *, exc_info=None)

class yapapi.events.ProposalConfirmed(job, proposal, *, exc_info=None)

class yapapi.events.ProposalFailed(job, proposal, *, exc_info=None)

class yapapi.events.NoProposalsConfirmed(job, timeout, *, exc_info=None): We didn’t confirm any proposal for a period of timeout

class yapapi.events.AgreementCreated(job, agreement, *, exc_info=None)

class yapapi.events.AgreementConfirmed(job, agreement, *, exc_info=None)

class yapapi.events.AgreementRejected(job, agreement, *, exc_info=None)

class yapapi.events.AgreementTerminated(job, agreement, reason, *, exc_info=None)

class yapapi.events.DebitNoteReceived(job, agreement, debit_note, *, exc_info=None)

class yapapi.events.DebitNoteAccepted(job, agreement, debit_note, *, exc_info=None)

class yapapi.events.PaymentPrepared(job, agreement, *, exc_info=None)

class yapapi.events.PaymentQueued(job, agreement, *, exc_info=None)

class yapapi.events.PaymentFailed(job, agreement, *, exc_info=None)

class yapapi.events.InvoiceReceived(job, agreement, invoice, *, exc_info=None)

class yapapi.events.InvoiceAccepted(job, agreement, invoice, *, exc_info=None)

class yapapi.events.WorkerStarted(job, agreement, *, exc_info=None)

class yapapi.events.ActivityCreated(job, agreement, activity, *, exc_info=None)

class yapapi.events.ActivityCreateFailed(job, agreement, *, exc_info=None)

class yapapi.events.TaskStarted(job, agreement, activity, task, *, exc_info=None)

class yapapi.events.TaskFinished(job, agreement, activity, task, *, exc_info=None)

class yapapi.events.ServiceStarted(job, agreement, activity, service, *, exc_info=None)

class yapapi.events.ServiceFinished(job, agreement, activity, service, *, exc_info=None)

class yapapi.events.WorkerFinished(job, agreement, activity, *, exc_info=None)

class yapapi.events.ScriptSent(job, agreement, activity, script, *, exc_info=None)

class yapapi.events.GettingResults(job, agreement, activity, script, *, exc_info=None)

class yapapi.events.ScriptFinished(job, agreement, activity, script, *, exc_info=None)

class yapapi.events.CommandExecuted(job, agreement, activity, script, command, success, message, stdout=None, stderr=None, *, exc_info=None)

class yapapi.events.CommandStarted(job, agreement, activity, script, command, *, exc_info=None)

class yapapi.events.CommandStdOut(job, agreement, activity, script, command, output, *, exc_info=None)

class yapapi.events.CommandStdErr(job, agreement, activity, script, command, output, *, exc_info=None)

class yapapi.events.TaskAccepted(job, agreement, activity, task, *, exc_info=None)

class yapapi.events.TaskRejected(job, agreement, activity, task, reason, *, exc_info=None)

class yapapi.events.DownloadStarted(job, agreement, activity, script, command, *, exc_info=None)

class yapapi.events.DownloadFinished(job, agreement, activity, script, command, *, exc_info=None)

class yapapi.events.ShutdownFinished(*, exc_info=None): Golem completed the shutdown sequence and is no longer operative

class yapapi.events.ExecutionInterrupted(*, exc_info=None): Golem was stopped by an unhandled exception in code not managed by yapapi

Exceptions

exception yapapi.NoPaymentAccountError(required_driver, required_network): The error raised if no payment account for the required driver/network is available.

exception yapapi.rest.activity.BatchTimeoutError: An exception that indicates that an execution of a batch of commands timed out.

Logging

yapapi.log.enable_default_logger(format_='[%(asctime)s %(levelname)s %(name)s] %(message)s', log_file=None, debug_activity_api=False, debug_market_api=False, debug_payment_api=False, debug_net_api=False)

Enable the default logger that logs messages to stderr with level INFO.

If log_file is specified, the logger with output messages with level DEBUG to the given file.

class yapapi.log.SummaryLogger(wrapped_emitter=None)

Aggregates information from computation events to provide a high-level summary.

The logger’s log() method can be used as event_consumer callback in Golem initialization. It will aggregate the events generated and output some summary information.

The optional wrapped_emitter argument can be used for chaining event emitters: each event logged with log() is first passed to wrapped_emitter.

For example, with the following setup, each event will be logged by log_event_repr, and additionally, certain events will cause summary messages to be logged.

detailed_logger = log_event_repr
summary_logger = SummaryLogger(wrapped_emitter=detailed_logger).log
golem = Golem(..., event_consumer=summary_logger)

log(event)

Register an event.

Return type: None

yapapi.log.log_summary(wrapped_emitter=None)

Output a summary of computation.

This is a utility function that creates a SummaryLogger instance wrapping an optional wrapped_emitter and returns its log() method.

See the documentation of SummaryLogger for more information.

Utils

yapapi.windows_event_loop_fix()

Set up asyncio to use ProactorEventLoop implementation for new event loops on Windows.

This work-around is only needed for Python 3.6 and 3.7. With Python 3.8, ProactorEventLoop is already the default on Windows.

yapapi.get_version()

Return type: str
Returns: the version of the yapapi library package

Contrib

Useful, reusable pieces of code built on top of Yapapi.

class yapapi.contrib.strategy.ProviderFilter(base_strategy, is_allowed)

ProviderFilter - extend a market strategy with a layer that excludes offers from certain issuers

Parameters

base_strategy (BaseMarketStrategy) – a market strategy that will be used to score offers from allowed providers
is_allowed (Union[Callable[[str], bool], Callable[[str], Awaitable[bool]]]) – a callable that accepts provider_id as an argument and returns either a boolean, or a boolean-returning awaitable, determining if offers from this provider should be considered (that is: scored by the base_strategy)

Example 1. Block selected providers:

bad_providers = ['bad_provider_1', 'bad_provider_2']
base_strategy = SomeStrategy(...)
strategy = ProviderFilter(base_strategy, lambda provider_id: provider_id not in bad_providers)

Example 2. Select providers using a database table:

#   create an async database connection
#   (sync would also work, but could hurt `yapapi` overall performance)
async_conn = ...

async def is_allowed(provider_id):
    result = await async_conn.execute("SELECT 1 FROM allowed_providers WHERE provider_id = ?", provider_id)
    return bool(result.fetchall())

base_strategy = SomeStrategy()
strategy = ProviderFilter(base_strategy, is_allowed)

Example 3. Use the default strategy, but disable every provider that fails to create an activity:

from yapapi import events

bad_providers = set()

def denying_event_consumer(event: events.Event):
    if isinstance(event, events.ActivityCreateFailed):
        bad_providers.add(event.provider_id)

golem = Golem(...)
golem.strategy = ProviderFilter(golem.strategy, lambda provider_id: provider_id not in bad_providers)
await golem.add_event_consumer(denying_event_consumer)

async with golem:
    ...

#   NOTE: this will currently work only for **new** offers from the provider, because old offers are already
#   scored, this should improve in https://github.com/golemfactory/yapapi/issues/820