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Matt's interfaces

03a1cf59a665945c4f5c65567c81f8ddb741071f · 2025-07-07 16:42:52 +0100 · Matt Beton

Added interfaces for chunks, worker, runner, supervisor, resourcemonitor, etc.

Files touched

• M master/api.py
• M pyproject.toml
• A shared/types/api.py
• A shared/types/events/chunks.py
• M shared/types/events/common.py
• M shared/types/events/events.py
• M shared/types/models/common.py
• A shared/types/models/model.py
• M shared/types/profiling/common.py
• M shared/types/tasks/common.py
• A shared/types/worker/commands_runner.py
• M shared/types/worker/common.py
• M shared/types/worker/downloads.py
• A shared/types/worker/mlx.py
• A shared/types/worker/resource_monitor.py
• M shared/types/worker/runners.py
• M shared/types/worker/shards.py
• A shared/utils.py

Diff

commit 03a1cf59a665945c4f5c65567c81f8ddb741071f
Author: Matt Beton <matthew.beton@gmail.com>
Date:   Mon Jul 7 16:42:52 2025 +0100

    Matt's interfaces
    
    Added interfaces for chunks, worker, runner, supervisor, resourcemonitor, etc.
---
 master/api.py                           |  5 +-
 pyproject.toml                          |  1 +
 shared/types/api.py                     | 10 ++++
 shared/types/events/chunks.py           | 89 ++++++++++++++++++++++++++++++++
 shared/types/events/common.py           |  8 ++-
 shared/types/events/events.py           | 20 ++++----
 shared/types/models/common.py           | 17 +-----
 shared/types/models/model.py            | 18 +++++++
 shared/types/profiling/common.py        | 47 ++++++++++++++++-
 shared/types/tasks/common.py            |  2 +-
 shared/types/worker/commands_runner.py  | 91 +++++++++++++++++++++++++++++++++
 shared/types/worker/common.py           |  3 +-
 shared/types/worker/downloads.py        |  4 +-
 shared/types/worker/mlx.py              | 13 +++++
 shared/types/worker/resource_monitor.py | 55 ++++++++++++++++++++
 shared/types/worker/runners.py          | 14 +++--
 shared/types/worker/shards.py           | 46 ++++++++++++++---
 shared/utils.py                         |  8 +++
 18 files changed, 403 insertions(+), 48 deletions(-)

diff --git a/master/api.py b/master/api.py
index 28c35ce1..50cc3bd3 100644
--- a/master/api.py
+++ b/master/api.py
@@ -1,6 +1,7 @@
 from typing import Protocol
 
-from shared.types.models.common import Model, ModelId
+from shared.types.models.common import ModelId
+from shared.types.models.model import ModelInfo
 from shared.types.models.sources import ModelSource
 from shared.types.networking.topology import ControlPlaneTopology, DataPlaneTopology
 from shared.types.worker.common import InstanceId
@@ -21,7 +22,7 @@ class ControlPlaneAPI(Protocol):
 
     def remove_instance(self, instance_id: InstanceId) -> None: ...
 
-    def get_model_data(self, model_id: ModelId) -> Model: ...
+    def get_model_data(self, model_id: ModelId) -> ModelInfo: ...
 
     def download_model(self, model_id: ModelId, model_source: ModelSource) -> None: ...
 
diff --git a/pyproject.toml b/pyproject.toml
index 73dca1bf..2e748695 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -66,6 +66,7 @@ only-include = ["pyproject.toml", "README.md"]
 [tool.basedpyright] 
 typeCheckingMode = "strict"
 failOnWarnings = true 
+stubPath = "stubs"
 
 reportAny = "error"
 reportUnknownVariableType = "error"
diff --git a/shared/types/api.py b/shared/types/api.py
new file mode 100644
index 00000000..1d5d9cfd
--- /dev/null
+++ b/shared/types/api.py
@@ -0,0 +1,10 @@
+from typing import Literal
+from pydantic import BaseModel
+from openai.types.chat.completion_create_params import CompletionCreateParams
+
+from shared.types.tasks.common import TaskId
+
+class ChatTask(BaseModel):
+  task_id: TaskId
+  kind: Literal["chat"] = "chat"
+  task_data: CompletionCreateParams
\ No newline at end of file
diff --git a/shared/types/events/chunks.py b/shared/types/events/chunks.py
new file mode 100644
index 00000000..67834aca
--- /dev/null
+++ b/shared/types/events/chunks.py
@@ -0,0 +1,89 @@
+from typing import Any, Literal, TypeVar, Generic, Annotated
+from collections.abc import AsyncGenerator
+from enum import Enum
+from pydantic import BaseModel, Field, TypeAdapter
+
+from shared.types.tasks.common import TaskId
+from shared.types.models.common import ModelId
+from shared.openai import FinishReason
+
+class ChunkType(str, Enum):
+    token = 'token'
+    image = 'image'
+
+ChunkT = TypeVar('ChunkT', bound=ChunkType)
+
+class BaseChunk(BaseModel, Generic[ChunkT]):
+    task_id: TaskId
+    idx: int
+    model: ModelId
+
+###
+
+class TokenChunkData(BaseModel):
+    text: str
+    token_id: int
+    finish_reason: FinishReason | None = None
+
+class ImageChunkData(BaseModel):
+    data: bytes
+
+###
+
+class TokenChunk(BaseChunk[ChunkType.token]):
+    chunk_data: TokenChunkData
+    chunk_type: Literal[ChunkType.token] = Field(
+        default=ChunkType.token, frozen=True
+    )
+
+class ImageChunk(BaseChunk[ChunkType.image]):
+    chunk_data: ImageChunkData
+    chunk_type: Literal[ChunkType.image] = Field(
+        default=ChunkType.image, frozen=True
+    )
+
+###
+
+GenerationChunk = Annotated[
+    TokenChunk | ImageChunk,
+    Field(discriminator="chunk_type")
+]
+GenerationChunkTypeAdapter: TypeAdapter[GenerationChunk] = TypeAdapter(GenerationChunk)
+
+# my_chunk: dict[str, Any] = TokenChunk(
+#     task_id=TaskId('nicerid'),
+#     idx=0,
+#     chunk_data=TokenChunkData(
+#         text='hello',
+#         token_id=12,
+#     ),
+#     chunk_type=ChunkType.token,
+#     model='llama-3.1',
+# ).model_dump()
+# print(my_chunk)
+# restored = GenerationChunkTypeAdapter.validate_python(my_chunk)
+# print(restored)
+
+#### OpenAI API Interfaces ### 
+
+from openai.types.chat.chat_completion import ChatCompletion
+from openai.types.chat.chat_completion_chunk import ChatCompletionChunk
+
+OpenAIResponse = ChatCompletion | ChatCompletionChunk ## Currently we only support chat completions
+
+def send_task(task: Any) -> AsyncGenerator[GenerationChunk]:
+    """
+    This is the 'command' - turns the task into an event and pushes to the event queue.
+    Tokens are then read off the event queue and pushed back to the api via an AsyncGenerator.
+    """
+    ...
+
+def parse_chunk_to_openai_response(chunk: GenerationChunk) -> OpenAIResponse:
+    ...
+
+async def handle_task(task: Any) -> AsyncGenerator[OpenAIResponse]:
+    ## In our api call function, we will do:
+    generator: AsyncGenerator[GenerationChunk] = send_task(task)
+
+    async for chunk in generator:
+        yield parse_chunk_to_openai_response(chunk)
diff --git a/shared/types/events/common.py b/shared/types/events/common.py
index ab920306..df759c53 100644
--- a/shared/types/events/common.py
+++ b/shared/types/events/common.py
@@ -16,8 +16,8 @@ from pydantic import BaseModel, Field, TypeAdapter, model_validator
 from shared.types.common import NewUUID, NodeId
 
 
-class EventId(NewUUID):
-    pass
+class EventId(NewUUID): pass
+class TimerId(NewUUID): pass
 
 
 class MLXEventTypes(str, Enum):
@@ -67,6 +67,9 @@ class TimerEventTypes(str, Enum):
     TimerCreated = "TimerCreated"
     TimerFired = "TimerFired"
 
+class ResourceEventTypes(str, Enum):
+    ResourceProfiled = "ResourceProfiled"
+
 
 EventTypes = Union[
     TaskEventTypes,
@@ -78,6 +81,7 @@ EventTypes = Union[
     DataPlaneEventTypes,
     TimerEventTypes,
     MLXEventTypes,
+    ResourceEventTypes,
 ]
 
 EventTypeT = TypeVar("EventTypeT", bound=EventTypes)
diff --git a/shared/types/events/events.py b/shared/types/events/events.py
index 712e8936..a2c9bc08 100644
--- a/shared/types/events/events.py
+++ b/shared/types/events/events.py
@@ -4,7 +4,8 @@ from typing import Any, Literal, Tuple
 
 from pydantic import BaseModel
 
-from shared.types.common import NewUUID, NodeId
+from shared.types.common import NodeId
+from shared.types.events.common import TimerId
 from shared.types.events.common import (
     ControlPlaneEventTypes,
     DataPlaneEventTypes,
@@ -16,6 +17,7 @@ from shared.types.events.common import (
     StreamingEventTypes,
     TaskEventTypes,
     TimerEventTypes,
+    ResourceEventTypes,
 )
 from shared.types.networking.control_plane import (
     ControlPlaneEdgeId,
@@ -41,14 +43,7 @@ from shared.types.tasks.common import (
 from shared.types.worker.common import InstanceId, NodeStatus
 from shared.types.worker.instances import InstanceData, InstanceStatus
 from shared.types.worker.runners import RunnerId, RunnerState, RunnerStateType
-
-
-class RequestId(NewUUID):
-    pass
-
-
-class TimerId(NewUUID):
-    pass
+from shared.types.profiling.common import ProfiledResourceName
 
 
 class TimerData(BaseModel):
@@ -205,3 +200,10 @@ class TimerScheduled(Event[TimerEventTypes.TimerCreated]):
 class TimerFired(Event[TimerEventTypes.TimerFired]):
     event_type: Literal[TimerEventTypes.TimerFired] = TimerEventTypes.TimerFired
     timer_data: TimerData
+
+class ResourceProfiled(Event[ResourceEventTypes.ResourceProfiled]):
+    event_type: Literal[ResourceEventTypes.ResourceProfiled] = (
+        ResourceEventTypes.ResourceProfiled
+    ) 
+    resource_name: ProfiledResourceName
+    resource_profile: NodePerformanceProfile
\ No newline at end of file
diff --git a/shared/types/models/common.py b/shared/types/models/common.py
index d4471eb3..c65cd884 100644
--- a/shared/types/models/common.py
+++ b/shared/types/models/common.py
@@ -1,18 +1,3 @@
-from typing import Sequence, final
-
-from pydantic import BaseModel
-
 from shared.types.common import NewUUID
-from shared.types.models.metadata import ModelMetadata
-from shared.types.models.sources import ModelSource
-
-
-class ModelId(NewUUID):
-    pass
-
 
-@final
-class Model(BaseModel):
-    model_id: ModelId
-    model_sources: Sequence[ModelSource]
-    model_metadata: ModelMetadata
+class ModelId(NewUUID): pass
\ No newline at end of file
diff --git a/shared/types/models/model.py b/shared/types/models/model.py
new file mode 100644
index 00000000..8588f043
--- /dev/null
+++ b/shared/types/models/model.py
@@ -0,0 +1,18 @@
+from typing import final, Sequence
+
+from pydantic import BaseModel, TypeAdapter
+
+from shared.types.models.common import ModelId
+from shared.types.models.metadata import ModelMetadata
+from shared.types.models.sources import ModelSource
+
+
+@final
+# Concerned by the naming here; model could also be an instance of a model.
+class ModelInfo(BaseModel):
+    model_id: ModelId
+    model_sources: Sequence[ModelSource]
+    model_metadata: ModelMetadata
+
+
+ModelIdAdapter: TypeAdapter[ModelId] = TypeAdapter(ModelId)
\ No newline at end of file
diff --git a/shared/types/profiling/common.py b/shared/types/profiling/common.py
index 0c09b8f3..ecf07729 100644
--- a/shared/types/profiling/common.py
+++ b/shared/types/profiling/common.py
@@ -1,4 +1,47 @@
-from pydantic import BaseModel
+from typing import Annotated, Literal, Coroutine, Generic, TypeVar
+from enum import Enum
+from abc import ABC
+from pydantic import BaseModel, Field, TypeAdapter
 
 
-class NodePerformanceProfile(BaseModel): ...
+class ProfiledResourceName(str, Enum):
+    memory = 'memory'   
+    system = 'system'
+
+ProfiledResourceT = TypeVar(name='ProfiledResourceT', bound=ProfiledResourceName)
+
+class BasePerformanceProfile(BaseModel, Generic[ProfiledResourceT]):
+    """
+    Details a single resource (or resource type) that is being monitored by the resource monitor.
+    """
+    pass
+
+class MemoryPerformanceProfile(BasePerformanceProfile[ProfiledResourceName.memory]):
+    resource_name: Literal[ProfiledResourceName.memory] = Field(
+        default=ProfiledResourceName.memory, frozen=True
+    )
+    ram_total: int
+    ram_used: int
+    swap_total: int
+    swap_used: int
+
+class NetworkInterfaceInfo(BaseModel):
+    name: str
+    ip_address: str
+    type: str
+
+class SystemPerformanceProfile(BasePerformanceProfile[ProfiledResourceName.system]):
+    resource_name: Literal[ProfiledResourceName.system] = Field(
+        default=ProfiledResourceName.system, frozen=True
+    )
+    model_id: str
+    chip_id: str
+    memory: int
+    network_interfaces: list[NetworkInterfaceInfo] = Field(default_factory=list)
+
+NodePerformanceProfile = Annotated[
+    MemoryPerformanceProfile | SystemPerformanceProfile,
+    Field(discriminator="resource_name")
+]
+
+NodePerformanceProfileTypeAdapter: TypeAdapter[NodePerformanceProfile] = TypeAdapter(NodePerformanceProfile)
\ No newline at end of file
diff --git a/shared/types/tasks/common.py b/shared/types/tasks/common.py
index 114c0550..886ac51b 100644
--- a/shared/types/tasks/common.py
+++ b/shared/types/tasks/common.py
@@ -1,6 +1,6 @@
 from collections.abc import Mapping
 from enum import Enum
-from typing import Annotated, Generic, Literal, TypeVar, Union
+from typing import Annotated, Generic, Literal, TypeVar
 
 import openai.types.chat as openai
 from pydantic import BaseModel, Field, TypeAdapter
diff --git a/shared/types/worker/commands_runner.py b/shared/types/worker/commands_runner.py
new file mode 100644
index 00000000..5a4b8cfa
--- /dev/null
+++ b/shared/types/worker/commands_runner.py
@@ -0,0 +1,91 @@
+from typing import Annotated, Generic, Literal, TypeVar
+from enum import Enum
+from pydantic import BaseModel, Field, TypeAdapter
+
+from shared.types.api import ChatTask
+from shared.types.worker.shards import ShardMeta
+from shared.types.worker.mlx import Host
+from shared.openai import FinishReason
+
+## Messages passed TO the runner
+
+class MessageType(str, Enum):
+    Setup = 'setup'
+    ChatTask = "chat_task"
+    Exit = 'exit'
+
+MT = TypeVar(name='MT', bound=MessageType)
+
+class BaseRunnerMessage(BaseModel, Generic[MT]):
+    pass
+
+class SetupMessage(BaseRunnerMessage[MessageType.Setup]):
+    type: Literal[MessageType.Setup] = Field(
+        default=MessageType.Setup, frozen=True
+    )
+    model_shard_meta: ShardMeta
+    hosts: list[Host]
+
+class ChatTaskMessage(BaseRunnerMessage[MessageType.ChatTask]):
+    type: Literal[MessageType.ChatTask] = Field(
+        default=MessageType.ChatTask, frozen=True
+    )
+    task: ChatTask
+
+class ExitMessage(BaseRunnerMessage[MessageType.Exit]):
+    type: Literal[MessageType.Exit] = Field(
+        default=MessageType.Exit, frozen=True
+    )
+
+RunnerMessage = Annotated[
+    SetupMessage | ChatTaskMessage | ExitMessage,
+    Field(discriminator="type")
+]
+RunnerMessageTypeAdapter: TypeAdapter[RunnerMessage] = TypeAdapter(RunnerMessage)
+
+## Responses passed FROM the runner
+
+class RunnerResponseType(str, Enum):
+    GenerationResponse = "generation_response"
+    FinishedResponse = "finished_response"
+    PrintResponse = "print_response"
+    ErrorResponse = "error_response"
+
+RRT = TypeVar(name='RRT', bound=RunnerResponseType)
+
+class BaseRunnerResponse(BaseModel, Generic[RRT]):
+    pass
+
+class GenerationResponse(BaseRunnerResponse[RunnerResponseType.GenerationResponse]):
+  type: Literal[RunnerResponseType.GenerationResponse] = Field(
+    default=RunnerResponseType.GenerationResponse, frozen=True
+  )
+  text: str
+  token: int
+  # logprobs: Optional[list[float]] = None # too big. we can change to be top-k
+  finish_reason: FinishReason | None = None
+
+class PrintResponse(BaseRunnerResponse[RunnerResponseType.PrintResponse]):
+  type: Literal[RunnerResponseType.PrintResponse] = Field(
+    default=RunnerResponseType.PrintResponse, frozen=True
+  )
+  text: str
+
+class FinishedResponse(BaseRunnerResponse[RunnerResponseType.FinishedResponse]):
+  type: Literal[RunnerResponseType.FinishedResponse] = Field(
+    default=RunnerResponseType.FinishedResponse, frozen=True
+  )
+
+class ErrorResponse(BaseRunnerResponse[RunnerResponseType.ErrorResponse]):
+  type: Literal[RunnerResponseType.ErrorResponse] = Field(
+    default=RunnerResponseType.ErrorResponse, frozen=True
+  )
+  error_type: str
+  error_message: str
+  traceback: str | None = None
+
+RunnerResponse = Annotated[
+    GenerationResponse | PrintResponse | FinishedResponse | ErrorResponse,
+    Field(discriminator="type")
+]
+RunnerResponseTypeAdapter: TypeAdapter[RunnerResponse] = TypeAdapter(RunnerResponse)
diff --git a/shared/types/worker/common.py b/shared/types/worker/common.py
index 5fa78f74..786e0e73 100644
--- a/shared/types/worker/common.py
+++ b/shared/types/worker/common.py
@@ -2,7 +2,6 @@ from enum import Enum
 
 from shared.types.common import NewUUID
 
-
 class InstanceId(NewUUID):
     pass
 
@@ -14,4 +13,4 @@ class RunnerId(NewUUID):
 class NodeStatus(str, Enum):
     Idle = "Idle"
     Running = "Running"
-    Paused = "Paused"
+    Paused = "Paused"
\ No newline at end of file
diff --git a/shared/types/worker/downloads.py b/shared/types/worker/downloads.py
index c46da775..c539fb9c 100644
--- a/shared/types/worker/downloads.py
+++ b/shared/types/worker/downloads.py
@@ -15,7 +15,7 @@ from pydantic import BaseModel, Field, PositiveInt
 from shared.types.common import NodeId
 from shared.types.models.common import ModelId
 from shared.types.models.sources import ModelSource
-from shared.types.worker.shards import ShardData, ShardType
+from shared.types.worker.shards import ShardMeta
 
 
 class DownloadProgressData(BaseModel):
@@ -80,6 +80,6 @@ DownloadEffectHandler = Callable[
 def download_shard(
     model_id: ModelId,
     model_source: ModelSource,
-    shard_data: ShardData[ShardType],
+    shard_meta: ShardMeta,
     effect_handlers: Sequence[DownloadEffectHandler],
 ) -> None: ...
diff --git a/shared/types/worker/mlx.py b/shared/types/worker/mlx.py
new file mode 100644
index 00000000..0d5db1f5
--- /dev/null
+++ b/shared/types/worker/mlx.py
@@ -0,0 +1,13 @@
+from pydantic import BaseModel, field_validator
+
+
+# TODO: Is this the right place for this? Host is consumed by worker, but typically stored in the master
+class Host(BaseModel):
+    host: str
+    port: int
+
+    @field_validator('port')
+    def check_port(cls, v: int) -> int:
+        if not (0 <= v <= 65535):
+            raise ValueError("Port must be between 0 and 65535")
+        return v
\ No newline at end of file
diff --git a/shared/types/worker/resource_monitor.py b/shared/types/worker/resource_monitor.py
new file mode 100644
index 00000000..7ac27b2f
--- /dev/null
+++ b/shared/types/worker/resource_monitor.py
@@ -0,0 +1,55 @@
+from abc import ABC
+from collections.abc import Coroutine
+
+import asyncio
+
+from shared.types.events.events import ResourceProfiledEvent
+from shared.types.profiling.common import NodePerformanceProfile, MemoryPerformanceProfile, SystemPerformanceProfile
+
+class EventLog:
+    def append(self, event: ResourceProfiledEvent) -> None:
+        ...
+
+class ResourceCollector(ABC):
+    """
+    Details a single resource (or resource type) that is being monitored by the resource monitor.
+    """
+    def __init__(self, name: str):
+        self.name = name
+
+    async def collect(self) -> NodePerformanceProfile:
+        ...
+
+class SystemResourceCollector(ResourceCollector):
+    def __init__(self):
+        super().__init__('system')
+
+    async def collect(self) -> SystemPerformanceProfile:
+        ...
+
+class MemoryResourceCollector(ResourceCollector):
+    def __init__(self):
+        super().__init__('memory')
+
+    async def collect(self) -> MemoryPerformanceProfile:
+        ...
+
+class ResourceMonitor:
+    def __init__(self, event_outbox: EventLog):
+        self.event_outbox: EventLog = event_outbox
+
+        self.collectors: list[ResourceCollector] = [
+            SystemResourceCollector(),
+            MemoryResourceCollector(),
+        ]
+
+    async def collect(self) -> list[NodePerformanceProfile]:
+        tasks: list[Coroutine[None, None, NodePerformanceProfile]] = [
+            collector.collect() for collector in self.collectors
+        ]
+        return await asyncio.gather(*tasks)
+
+    async def collect_and_publish(self) -> None:
+        profiles = await self.collect()
+        for profile in profiles:
+            self.event_outbox.append(profile.to_event())
\ No newline at end of file
diff --git a/shared/types/worker/runners.py b/shared/types/worker/runners.py
index 1ca1dc22..dca7b290 100644
--- a/shared/types/worker/runners.py
+++ b/shared/types/worker/runners.py
@@ -1,6 +1,6 @@
 from collections.abc import Mapping, Sequence
 from enum import Enum
-from typing import Generic, Literal, TypeVar
+from typing import Generic, Literal, TypeVar, Self
 
 from pydantic import BaseModel, model_validator
 
@@ -8,7 +8,7 @@ from shared.types.common import NodeId
 from shared.types.models.common import ModelId
 from shared.types.worker.common import RunnerId
 from shared.types.worker.downloads import BaseDownloadProgress, DownloadStatus
-from shared.types.worker.shards import ShardData, ShardType
+from shared.types.worker.shards import BaseModelShardMeta, PartitionStrategyT
 
 
 class RunnerStateType(str, Enum):
@@ -55,13 +55,17 @@ class RunnerData(BaseModel):
     )
 
 
-class RunnerPlacement(BaseModel):
+# Runner placement must be consistent in its partitioning strategy across all shards.
+# Using a generic type parameter enforces this constraint at type-checking time.
+
+
+class RunnerPlacement(BaseModel, Generic[PartitionStrategyT]):
     model_id: ModelId
-    runner_to_shard: Mapping[RunnerId, ShardData[ShardType]]
+    runner_to_shard: Mapping[RunnerId, BaseModelShardMeta[PartitionStrategyT]]
     node_to_runner: Mapping[NodeId, Sequence[RunnerId]]
 
     @model_validator(mode="after")
-    def validate_runners_exist(self) -> "RunnerPlacement":
+    def validate_runners_exist(self) -> Self:
         for runners in self.node_to_runner.values():
             for runner_id in runners:
                 if runner_id not in self.runner_to_shard:
diff --git a/shared/types/worker/shards.py b/shared/types/worker/shards.py
index f7a97a42..57291a79 100644
--- a/shared/types/worker/shards.py
+++ b/shared/types/worker/shards.py
@@ -1,15 +1,47 @@
 from enum import Enum
-from typing import Generic, TypeVar
+from typing import Generic, TypeVar, Annotated, Literal
 
-from pydantic import BaseModel
+from pydantic import BaseModel, DirectoryPath, Field, TypeAdapter
 
+from shared.types.common import NodeId
+from shared.types.models.common import ModelId
 
-class ShardType(str, Enum):
-    PipelineParallel = "PipelineParallel"
+class PartitionStrategy(str, Enum):
+    pipeline = 'pipeline'
 
+PartitionStrategyT = TypeVar(name='PartitionStrategyT', bound=PartitionStrategy)
 
-ShardTypeT = TypeVar("ShardTypeT", bound=ShardType)
+class BaseModelShardMeta(BaseModel, Generic[PartitionStrategyT]):
+    """
+    Defines a specific shard of the model that is ready to be run on a device.
+    Replaces previous `Shard` object.
+    """
+    device_rank: int
+    world_size: int
+    model_id: ModelId
+    model_path: DirectoryPath # pydantic DirectoryPath ensures that the directory exists.
 
+class PipelineShardMeta(BaseModelShardMeta[PartitionStrategy.pipeline]):
+    """
+    Pipeline parallelism shard meta.
+    """
+    partition_strategy: Literal[PartitionStrategy.pipeline] = Field(
+        default=PartitionStrategy.pipeline, frozen=True
+    )
+    start_layer: Annotated[int, Field(ge=0)]
+    end_layer: Annotated[int, Field(ge=0)]
 
-class ShardData(BaseModel, Generic[ShardTypeT]):
-    shard_type: ShardTypeT
+ShardMeta = Annotated[
+    PipelineShardMeta,
+    Field(discriminator="partition_strategy")
+]
+ShardMetaAdapter: TypeAdapter[ShardMeta] = TypeAdapter(ShardMeta)
+
+
+class ShardPlacement(BaseModel, Generic[PartitionStrategyT]):
+    """
+    A shard placement is the description of a model distributed across a set of nodes.
+    The Generic[PartitionStrategyT] enforces that the shard assignments all use the same partition strategy.
+    """
+    model_id: ModelId
+    shard_assignments: dict[NodeId, BaseModelShardMeta[PartitionStrategyT]]
diff --git a/shared/utils.py b/shared/utils.py
new file mode 100644
index 00000000..3a9acce1
--- /dev/null
+++ b/shared/utils.py
@@ -0,0 +1,8 @@
+from typing import Any, Type, TypeVar
+
+T = TypeVar('T')
+
+def ensure_type(obj: Any, expected_type: Type[T]) -> T:
+    if not isinstance(obj, expected_type):
+        raise TypeError(f"Expected {expected_type}, got {type(obj)}")
+    return obj
\ No newline at end of file

← 367e76c8 fix: Fix validation over Task types  ·  back to Exo  ·  Simple fix 0425422f →