fix: separate fastapi and yaml dependencies (#603)

faststream/__about__.py

@@ -1,2 +1,8 @@
 """Simple and fast framework to create message brokers based microservices"""
 __version__ = "0.0.1-dev20230912"
+
+
+INSTALL_YAML = """
+To generate YAML documentation, please install dependencies:\n
+pip install PyYAML
+"""

faststream/asyncapi/generate.py

@@ -1,5 +1,6 @@
 from typing import Any, Dict, Union
 
+from faststream._compat import is_installed
 from faststream.app import FastStream
 from faststream.asyncapi.schema import (
     Channel,
@@ -10,11 +11,12 @@
     Schema,
     Server,
 )
-from faststream.broker.fastapi.router import StreamRouter
 from faststream.constants import ContentTypes
 
+if is_installed("fastapi"):
+    from faststream.broker.fastapi.router import StreamRouter
 
-def get_app_schema(app: Union[FastStream, StreamRouter[Any]]) -> Schema:
+def get_app_schema(app: Union[FastStream, "StreamRouter[Any]"]) -> Schema:
     """Get the application schema.
 
     Args:
@@ -95,7 +97,7 @@ def get_app_schema(app: Union[FastStream, StreamRouter[Any]]) -> Schema:
 
 
 def get_app_broker_server(
-    app: Union[FastStream, StreamRouter[Any]]
+    app: Union[FastStream, "StreamRouter[Any]"]
 ) -> Dict[str, Server]:
     """Get the broker server for an application.
 
@@ -149,7 +151,7 @@ def get_app_broker_server(
 
 
 def get_app_broker_channels(
-    app: Union[FastStream, StreamRouter[Any]]
+    app: Union[FastStream, "StreamRouter[Any]"]
 ) -> Dict[str, Channel]:
     """Get the broker channels for an application.
 

faststream/cli/docs/app.py

@@ -4,8 +4,8 @@
 from typing import Optional
 
 import typer
-import yaml
 
+from faststream.__about__ import INSTALL_YAML
 from faststream._compat import model_parse
 from faststream.asyncapi.generate import get_app_schema
 from faststream.asyncapi.schema import Schema
@@ -41,9 +41,17 @@ def serve(
         schema_filepath = Path.cwd() / app
         if schema_filepath.suffix == ".json":
             data = schema_filepath.read_text()
+
         elif schema_filepath.suffix == ".yaml" or schema_filepath.suffix == ".yml":
+            try:
+                import yaml
+            except ImportError as e:  # pragma: no cover
+                typer.echo(INSTALL_YAML, err=True)
+                raise typer.Exit(1) from e
+
             with schema_filepath.open("r") as f:
                 schema = yaml.safe_load(f)
+
             data = json.dumps(schema)
         else:
             raise ValueError(
@@ -91,10 +99,7 @@ def gen(
         try:
             schema = raw_schema.to_yaml()
         except ImportError as e:  # pragma: no cover
-            typer.echo(
-                "To generate YAML documentation, please install dependencies:\n"
-                "pip install PyYAML"
-            )
+            typer.echo(INSTALL_YAML, err=True)
             raise typer.Exit(1) from e
 
         name = out or "asyncapi.yaml"
@@ -108,3 +113,5 @@ def gen(
 
         with open(name, "w") as f:
             json.dump(schema, f, indent=2)
+
+    typer.echo(f"Your project AsyncAPI scheme was placed to `{name}`")