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POC: deploy a streamable HTTP server on Databricks apps and connect to it from the client #1

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POC: deploy a streamable HTTP server on Databricks apps and connect to it from the client #1

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POC: deploy a streamable HTTP server on Databricks apps and connect t…
smurching May 7, 2025
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9 changes: 9 additions & 0 deletions examples/servers/simple-streamablehttp/app.yaml
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Original file line number Diff line number Diff line change
@@ -0,0 +1,9 @@
command: [
"uv",
"run",
"mcp-simple-streamablehttp",
"--port",
"8000",

@smurching smurching May 7, 2025 •
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Using port 8000 since that's what apps exposes by default, though this is configurable via environment variable

"--log-level",
"DEBUG"
]
5 changes: 4 additions & 1 deletion examples/servers/simple-streamablehttp/pyproject.toml
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@@ -1,3 +1,6 @@
[tool.hatch.metadata]
allow-direct-references = true

[project]
name = "mcp-simple-streamablehttp"
version = "0.1.0"
Expand All @@ -7,7 +10,7 @@ requires-python = ">=3.10"
authors = [{ name = "Anthropic, PBC." }]
keywords = ["mcp", "llm", "automation", "web", "fetch", "http", "streamable"]
license = { text = "MIT" }
dependencies = ["anyio>=4.5", "click>=8.1.0", "httpx>=0.27", "mcp", "starlette", "uvicorn"]
dependencies = ["anyio>=4.5", "click>=8.1.0", "httpx>=0.27", "mcp @ git+https://github.com/modelcontextprotocol/python-sdk.git@main", "starlette", "uvicorn"]

[project.scripts]
mcp-simple-streamablehttp = "mcp_simple_streamablehttp.server:main"
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1 change: 1 addition & 0 deletions examples/servers/simple-streamablehttp/requirements.txt
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@@ -0,0 +1 @@
uv
2 changes: 1 addition & 1 deletion src/mcp/shared/session.py
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Expand Up @@ -248,7 +248,7 @@ async def send_request(
)

# request read timeout takes precedence over session read timeout
timeout = None
timeout = 10
if request_read_timeout_seconds is not None:
timeout = request_read_timeout_seconds.total_seconds()
elif self._session_read_timeout_seconds is not None:
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21 changes: 13 additions & 8 deletions tests/shared/test_streamable_http.py
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Expand Up @@ -439,7 +439,10 @@ def json_response_server(json_server_port: int) -> Generator[None, None, None]:
@pytest.fixture
def basic_server_url(basic_server_port: int) -> str:
"""Get the URL for the basic test server."""
return f"http://127.0.0.1:{basic_server_port}"
# TODO(smurching) update this to point to the Databricks apps URL
res = f"https://unity-catalog-mcp-1444828305810485.aws.databricksapps.com"
print("basic_server_url", res)
return res


@pytest.fixture
Expand Down Expand Up @@ -776,7 +779,8 @@ async def http_client(basic_server, basic_server_url):
@pytest.fixture
async def initialized_client_session(basic_server, basic_server_url):
"""Create initialized StreamableHTTP client session."""
async with streamablehttp_client(f"{basic_server_url}/mcp") as (
token = "TODO add token here"

@smurching smurching May 7, 2025 •
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I used code like this to get an oauth token, after doing databricks auth login --profile fieldeng-oauth:

from databricks import sdk

w = sdk.WorkspaceClient(profile="fieldeng-oauth")
headers = w.config.authenticate()
print(headers)

Using a PAT to talk to apps doesn't work

async with streamablehttp_client(url=f"{basic_server_url}/mcp/", headers={'Authorization': f'Bearer {token}'}) as (

@smurching smurching May 8, 2025

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Note: when running against the example server in the MCP repo, the client has to connect to /mcp/

read_stream,
write_stream,
_,
Expand Down Expand Up @@ -823,14 +827,15 @@ async def test_streamablehttp_client_tool_invocation(initialized_client_session)
"""Test client tool invocation."""
# First list tools
tools = await initialized_client_session.list_tools()
assert len(tools.tools) == 3
assert tools.tools[0].name == "test_tool"
assert len(tools.tools) == 1
assert tools.tools[0].name == "start-notification-stream"

# Call the tool
result = await initialized_client_session.call_tool("test_tool", {})
assert len(result.content) == 1
assert result.content[0].type == "text"
assert result.content[0].text == "Called test_tool"
result = await initialized_client_session.call_tool("start-notification-stream", {"interval": 1.0, "count": 5, "caller": "test-caller"})
assert len(result.content) == 1, result.content

# assert result.content[0].type == "text"
# assert result.content[0].text == "Called test_tool"


@pytest.mark.anyio
Expand Down