Add support for running flows by endpoint name (#2012)

* feat: Add support for running flows by endpoint name

This commit modifies the `simplified_run_flow` endpoint in `endpoints.py` to allow running flows using the endpoint name instead of the flow ID. It introduces a new route parameter `flow_id_or_name` which can accept either a UUID or a string representing the endpoint name. The code first attempts to parse the parameter as a UUID, and if that fails, it queries the database to find a flow with the matching endpoint name. This change improves the usability of the API by providing an alternative way to identify flows for execution.

* feat: Add endpoint_name field to FlowType

This commit adds the `endpoint_name` field to the `FlowType` interface in the `index.ts` file. The `endpoint_name` field is an optional string that represents the name of the endpoint associated with the flow. This change allows for more flexibility in identifying flows by endpoint name instead of just the flow ID. It improves the usability of the codebase by providing an alternative way to reference flows.

* 🐛 (endpoints.py): change type of flow_id_or_name parameter from Union[str, UUID] to str to simplify the API and improve readability

* feat: Add migration utility functions for table, column, foreign key, and constraint existence checks

This commit adds utility functions to the `migration.py` module in the `langflow.utils` package. These functions provide convenient ways to check the existence of tables, columns, foreign keys, and constraints in a database using SQLAlchemy. The functions `table_exists`, `column_exists`, `foreign_key_exists`, and `constraint_exists` take the table name, column name, foreign key name, and constraint name respectively, along with the SQLAlchemy engine or connection object. They use the `Inspector` class from `sqlalchemy.engine.reflection` to retrieve the necessary information and return a boolean value indicating whether the specified element exists in the database. These utility functions improve the readability and maintainability of the codebase by encapsulating the common existence checks in a reusable and modular way.

* feat: Add unique constraints for per-user folders and flows

This commit adds unique constraints for per-user folders and flows in the database. It introduces the `unique_folder_name` constraint for the `folder` table, ensuring that each user can have only one folder with a specific name. Similarly, it adds the `unique_flow_endpoint_name` and `unique_flow_name` constraints for the `flow` table, enforcing uniqueness of endpoint names and flow names per user. These constraints improve data integrity and prevent duplicate entries in the database, providing a more robust and reliable system.

* feat: Add poetry installation and caching steps to GitHub Actions workflow

This commit updates the GitHub Actions workflow file `action.yml` to include additional steps for installing poetry and caching its dependencies. The `run` step now installs poetry using the specified version and ensures that the poetry binary is available in the PATH. Additionally, the workflow now includes a step to restore pip and poetry cached dependencies using the `actions/cache` action. These changes improve the workflow by providing a more efficient and reliable way to manage poetry dependencies and caching.

* refactor: Improve error handling in update_flow function

This commit improves the error handling in the `update_flow` function in `flows.py`. It adds a new `elif` condition to check if the exception is an instance of `HTTPException` and re-raises it. This ensures that any `HTTPException` raised during the update process is properly handled and returned as a response. Additionally, it removes the unnecessary `else` block and simplifies the code logic. This refactor enhances the reliability and maintainability of the `update_flow` function.

.github/actions/poetry_caching/action.yml

@@ -77,7 +77,12 @@ runs:
         POETRY_VERSION: ${{ inputs.poetry-version }}
         PYTHON_VERSION: ${{ inputs.python-version }}
       # Install poetry using the python version installed by setup-python step.
-      run: pipx install "poetry==$POETRY_VERSION" --python '${{ steps.setup-python.outputs.python-path }}' --verbose
+      run: |
+        pipx install "poetry==$POETRY_VERSION" --python '${{ steps.setup-python.outputs.python-path }}' --verbose
+        pipx ensurepath
+        # Ensure the poetry binary is available in the PATH.
+        # Test that the poetry binary is available.
+        poetry --version
 
     - name: Restore pip and poetry cached dependencies
       uses: actions/cache@v4

src/backend/base/langflow/alembic/script.py.mako

@@ -11,6 +11,7 @@ from alembic import op
 import sqlalchemy as sa
 import sqlmodel
 from sqlalchemy.engine.reflection import Inspector
+from langflow.utils import migration
 ${imports if imports else ""}
 
 # revision identifiers, used by Alembic.
@@ -22,13 +23,9 @@ depends_on: Union[str, Sequence[str], None] = ${repr(depends_on)}
 
 def upgrade() -> None:
     conn = op.get_bind()
-    inspector = Inspector.from_engine(conn)  # type: ignore
-    table_names = inspector.get_table_names()
     ${upgrades if upgrades else "pass"}
 
 
 def downgrade() -> None:
     conn = op.get_bind()
-    inspector = Inspector.from_engine(conn)  # type: ignore
-    table_names = inspector.get_table_names()
     ${downgrades if downgrades else "pass"}

src/backend/base/langflow/alembic/versions/1c79524817ed_add_unique_constraints_per_user_in_.py

@@ -0,0 +1,42 @@
+"""Add unique constraints per user in folder table
+
+Revision ID: 1c79524817ed
+Revises: 3bb0ddf32dfb
+Create Date: 2024-05-29 23:12:09.146880
+
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+from sqlalchemy.engine.reflection import Inspector
+
+# revision identifiers, used by Alembic.
+revision: str = "1c79524817ed"
+down_revision: Union[str, None] = "3bb0ddf32dfb"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+    inspector = Inspector.from_engine(conn)  # type: ignore
+    constraints_names = [constraint["name"] for constraint in inspector.get_unique_constraints("folder")]
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table("folder", schema=None) as batch_op:
+        if "unique_folder_name" not in constraints_names:
+            batch_op.create_unique_constraint("unique_folder_name", ["user_id", "name"])
+
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    conn = op.get_bind()
+    inspector = Inspector.from_engine(conn)  # type: ignore
+    constraints_names = [constraint["name"] for constraint in inspector.get_unique_constraints("folder")]
+    # ### commands auto generated by Alembic - please adjust! ###
+    with op.batch_alter_table("folder", schema=None) as batch_op:
+        if "unique_folder_name" in constraints_names:
+            batch_op.drop_constraint("unique_folder_name", type_="unique")
+
+    # ### end Alembic commands ###

src/backend/base/langflow/alembic/versions/3bb0ddf32dfb_add_unique_constraints_per_user_in_flow_.py

@@ -0,0 +1,54 @@
+"""Add unique constraints per user in flow table
+
+Revision ID: 3bb0ddf32dfb
+Revises: a72f5cf9c2f9
+Create Date: 2024-05-29 23:08:43.935040
+
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+from sqlalchemy.engine.reflection import Inspector
+
+# revision identifiers, used by Alembic.
+revision: str = "3bb0ddf32dfb"
+down_revision: Union[str, None] = "a72f5cf9c2f9"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+    inspector = Inspector.from_engine(conn)  # type: ignore
+    # ### commands auto generated by Alembic - please adjust! ###
+    indexes_names = [index["name"] for index in inspector.get_indexes("flow")]
+    constraints_names = [constraint["name"] for constraint in inspector.get_unique_constraints("flow")]
+    with op.batch_alter_table("flow", schema=None) as batch_op:
+        if "ix_flow_endpoint_name" in indexes_names:
+            batch_op.drop_index("ix_flow_endpoint_name")
+            batch_op.create_index(batch_op.f("ix_flow_endpoint_name"), ["endpoint_name"], unique=False)
+        if "unique_flow_endpoint_name" not in constraints_names:
+            batch_op.create_unique_constraint("unique_flow_endpoint_name", ["user_id", "endpoint_name"])
+        if "unique_flow_name" not in constraints_names:
+            batch_op.create_unique_constraint("unique_flow_name", ["user_id", "name"])
+
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    conn = op.get_bind()
+    inspector = Inspector.from_engine(conn)  # type: ignore
+    # ### commands auto generated by Alembic - please adjust! ###
+    indexes_names = [index["name"] for index in inspector.get_indexes("flow")]
+    constraints_names = [constraint["name"] for constraint in inspector.get_unique_constraints("flow")]
+    with op.batch_alter_table("flow", schema=None) as batch_op:
+        if "unique_flow_name" in constraints_names:
+            batch_op.drop_constraint("unique_flow_name", type_="unique")
+        if "unique_flow_endpoint_name" in constraints_names:
+            batch_op.drop_constraint("unique_flow_endpoint_name", type_="unique")
+        if "ix_flow_endpoint_name" in indexes_names:
+            batch_op.drop_index(batch_op.f("ix_flow_endpoint_name"))
+            batch_op.create_index("ix_flow_endpoint_name", ["endpoint_name"], unique=1)
+
+    # ### end Alembic commands ###

src/backend/base/langflow/alembic/versions/a72f5cf9c2f9_add_endpoint_name_col.py

@@ -0,0 +1,52 @@
+"""Add endpoint name col
+
+Revision ID: a72f5cf9c2f9
+Revises: 29fe8f1f806b
+Create Date: 2024-05-29 21:44:04.240816
+
+"""
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+import sqlmodel
+from alembic import op
+from sqlalchemy.engine.reflection import Inspector
+
+# revision identifiers, used by Alembic.
+revision: str = "a72f5cf9c2f9"
+down_revision: Union[str, None] = "29fe8f1f806b"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    conn = op.get_bind()
+    inspector = Inspector.from_engine(conn)  # type: ignore
+    # ### commands auto generated by Alembic - please adjust! ###
+    column_names = [column["name"] for column in inspector.get_columns("flow")]
+    indexes = inspector.get_indexes("flow")
+    index_names = [index["name"] for index in indexes]
+    with op.batch_alter_table("flow", schema=None) as batch_op:
+        if "endpoint_name" not in column_names:
+            batch_op.add_column(sa.Column("endpoint_name", sqlmodel.sql.sqltypes.AutoString(), nullable=True))
+        if "ix_flow_endpoint_name" not in index_names:
+            batch_op.create_index(batch_op.f("ix_flow_endpoint_name"), ["endpoint_name"], unique=True)
+
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    conn = op.get_bind()
+    inspector = Inspector.from_engine(conn)  # type: ignore
+    # ### commands auto generated by Alembic - please adjust! ###
+    column_names = [column["name"] for column in inspector.get_columns("flow")]
+    indexes = inspector.get_indexes("flow")
+    index_names = [index["name"] for index in indexes]
+    with op.batch_alter_table("flow", schema=None) as batch_op:
+        if "ix_flow_endpoint_name" in index_names:
+            batch_op.drop_index(batch_op.f("ix_flow_endpoint_name"))
+        if "endpoint_name" in column_names:
+            batch_op.drop_column("endpoint_name")
+
+    # ### end Alembic commands ###

src/backend/base/langflow/api/v1/endpoints.py

@@ -53,10 +53,10 @@ def get_all(
         raise HTTPException(status_code=500, detail=str(exc)) from exc
 
 
-@router.post("/run/{flow_id}", response_model=RunResponse, response_model_exclude_none=True)
+@router.post("/run/{flow_id_or_name}", response_model=RunResponse, response_model_exclude_none=True)
 async def simplified_run_flow(
     db: Annotated[Session, Depends(get_session)],
-    flow_id: UUID,
+    flow_id_or_name: str,
     input_request: SimplifiedAPIRequest = SimplifiedAPIRequest(),
     stream: bool = False,
     api_key_user: User = Depends(api_key_security),
@@ -111,8 +111,21 @@ async def simplified_run_flow(
     This endpoint provides a powerful interface for executing flows with enhanced flexibility and efficiency, supporting a wide range of applications by allowing for dynamic input and output configuration along with performance optimizations through session management and caching.
     """
     session_id = input_request.session_id
-
+    endpoint_name = None
+    flow_id_str = None
     try:
+        try:
+            flow_id = UUID(flow_id_or_name)
+
+        except ValueError:
+            endpoint_name = flow_id_or_name
+            flow = db.exec(
+                select(Flow).where(Flow.endpoint_name == endpoint_name).where(Flow.user_id == api_key_user.id)
+            ).first()
+            if flow is None:
+                raise ValueError(f"Flow with endpoint name {endpoint_name} not found")
+            flow_id = flow.id
+
         flow_id_str = str(flow_id)
         artifacts = {}
         if input_request.session_id:
@@ -172,10 +185,13 @@ async def simplified_run_flow(
             # This means the Flow ID is not a valid UUID which means it can't find the flow
             raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail=str(exc)) from exc
     except ValueError as exc:
-        if f"Flow {flow_id_str} not found" in str(exc):
+        if flow_id_str and f"Flow {flow_id_str} not found" in str(exc):
             logger.error(f"Flow {flow_id_str} not found")
             raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail=str(exc)) from exc
-        elif f"Session {session_id} not found" in str(exc):
+        elif endpoint_name and f"Flow with endpoint name {endpoint_name} not found" in str(exc):
+            logger.error(f"Flow with endpoint name {endpoint_name} not found")
+            raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail=str(exc)) from exc
+        elif session_id and f"Session {session_id} not found" in str(exc):
             logger.error(f"Session {session_id} not found")
             raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail=str(exc)) from exc
         else:

src/backend/base/langflow/api/v1/flows.py

@@ -135,30 +135,49 @@ def update_flow(
     settings_service=Depends(get_settings_service),
 ):
     """Update a flow."""
-
-    db_flow = read_flow(
-        session=session,
-        flow_id=flow_id,
-        current_user=current_user,
-        settings_service=settings_service,
-    )
-    if not db_flow:
-        raise HTTPException(status_code=404, detail="Flow not found")
-    flow_data = flow.model_dump(exclude_unset=True)
-    if settings_service.settings.remove_api_keys:
-        flow_data = remove_api_keys(flow_data)
-    for key, value in flow_data.items():
-        if value is not None:
-            setattr(db_flow, key, value)
-    db_flow.updated_at = datetime.now(timezone.utc)
-    if db_flow.folder_id is None:
-        default_folder = session.exec(select(Folder).where(Folder.name == DEFAULT_FOLDER_NAME)).first()
-        if default_folder:
-            db_flow.folder_id = default_folder.id
-    session.add(db_flow)
-    session.commit()
-    session.refresh(db_flow)
-    return db_flow
+    try:
+        db_flow = read_flow(
+            session=session,
+            flow_id=flow_id,
+            current_user=current_user,
+            settings_service=settings_service,
+        )
+        if not db_flow:
+            raise HTTPException(status_code=404, detail="Flow not found")
+        flow_data = flow.model_dump(exclude_unset=True)
+        if settings_service.settings.remove_api_keys:
+            flow_data = remove_api_keys(flow_data)
+        for key, value in flow_data.items():
+            if value is not None:
+                setattr(db_flow, key, value)
+        db_flow.updated_at = datetime.now(timezone.utc)
+        if db_flow.folder_id is None:
+            default_folder = session.exec(select(Folder).where(Folder.name == DEFAULT_FOLDER_NAME)).first()
+            if default_folder:
+                db_flow.folder_id = default_folder.id
+        session.add(db_flow)
+        session.commit()
+        session.refresh(db_flow)
+        return db_flow
+    except Exception as e:
+        # If it is a validation error, return the error message
+        if hasattr(e, "errors"):
+            raise HTTPException(status_code=400, detail=str(e)) from e
+        elif "UNIQUE constraint failed" in str(e):
+            # Get the name of the column that failed
+            columns = str(e).split("UNIQUE constraint failed: ")[1].split(".")[1].split("\n")[0]
+            # UNIQUE constraint failed: flow.user_id, flow.name
+            # or UNIQUE constraint failed: flow.name
+            # if the column has id in it, we want the other column
+            column = columns.split(",")[1] if "id" in columns.split(",")[0] else columns.split(",")[0]
+
+            raise HTTPException(
+                status_code=400, detail=f"{column.capitalize().replace('_', ' ')} must be unique"
+            ) from e
+        elif isinstance(e, HTTPException):
+            raise e
+        else:
+            raise HTTPException(status_code=500, detail=str(e)) from e
 
 
 @router.delete("/{flow_id}", status_code=200)

src/backend/base/langflow/services/database/models/flow/model.py

@@ -1,13 +1,16 @@
 # Path: src/backend/langflow/services/database/models/flow/model.py
 
+import re
 import warnings
 from datetime import datetime, timezone
 from typing import TYPE_CHECKING, Dict, Optional
 from uuid import UUID, uuid4
 
 import emoji
 from emoji import purely_emoji  # type: ignore
+from fastapi import HTTPException, status
 from pydantic import field_serializer, field_validator
+from sqlalchemy import UniqueConstraint
 from sqlmodel import JSON, Column, Field, Relationship, SQLModel
 
 from langflow.schema.schema import Record
@@ -26,6 +29,24 @@ class FlowBase(SQLModel):
     is_component: Optional[bool] = Field(default=False, nullable=True)
     updated_at: Optional[datetime] = Field(default_factory=lambda: datetime.now(timezone.utc), nullable=True)
     folder_id: Optional[UUID] = Field(default=None, nullable=True)
+    endpoint_name: Optional[str] = Field(default=None, nullable=True, index=True)
+
+    @field_validator("endpoint_name")
+    @classmethod
+    def validate_endpoint_name(cls, v):
+        # Endpoint name must be a string containing only letters, numbers, hyphens, and underscores
+        if v is not None:
+            if not isinstance(v, str):
+                raise HTTPException(
+                    status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+                    detail="Endpoint name must be a string",
+                )
+            if not re.match(r"^[a-zA-Z0-9_-]+$", v):
+                raise HTTPException(
+                    status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+                    detail="Endpoint name must contain only letters, numbers, hyphens, and underscores",
+                )
+        return v
 
     @field_validator("icon_bg_color")
     def validate_icon_bg_color(cls, v):
@@ -128,6 +149,11 @@ def to_record(self):
         record = Record(data=data)
         return record
 
+    __table_args__ = (
+        UniqueConstraint("user_id", "name", name="unique_flow_name"),
+        UniqueConstraint("user_id", "endpoint_name", name="unique_flow_endpoint_name"),
+    )
+
 
 class FlowCreate(FlowBase):
     user_id: Optional[UUID] = None
@@ -145,3 +171,21 @@ class FlowUpdate(SQLModel):
     description: Optional[str] = None
     data: Optional[Dict] = None
     folder_id: Optional[UUID] = None
+    endpoint_name: Optional[str] = None
+
+    @field_validator("endpoint_name")
+    @classmethod
+    def validate_endpoint_name(cls, v):
+        # Endpoint name must be a string containing only letters, numbers, hyphens, and underscores
+        if v is not None:
+            if not isinstance(v, str):
+                raise HTTPException(
+                    status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+                    detail="Endpoint name must be a string",
+                )
+            if not re.match(r"^[a-zA-Z0-9_-]+$", v):
+                raise HTTPException(
+                    status_code=status.HTTP_422_UNPROCESSABLE_ENTITY,
+                    detail="Endpoint name must contain only letters, numbers, hyphens, and underscores",
+                )
+        return v