knafeh 1.1.0

QUIC-based RPC library with Python bindings
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166

use std::collections::HashMap;

use async_trait::async_trait;
use pyo3::prelude::*;
use pyo3::types::PyBytes;

use crate::error::{KnafehError, RpcStatusCode};
use crate::rpc::message::{RpcRequest, RpcResponse};
use crate::rpc::service::{MethodDescriptor, MethodKind, Service};
use crate::rpc::stream::{RpcStreamRequest, RpcStreamResponse};

/// A service handler that delegates to Python callables.
#[pyclass(name = "ServiceHandler")]
pub struct PyServiceHandler {
    pub(crate) name: String,
    pub(crate) handlers: HashMap<String, (Py<PyAny>, MethodKind)>,
}

#[pymethods]
impl PyServiceHandler {
    #[new]
    fn new(name: String) -> Self {
        Self {
            name,
            handlers: HashMap::new(),
        }
    }

    /// Register a unary handler for the given method name.
    fn add_unary_handler(&mut self, method: String, handler: Py<PyAny>) {
        self.handlers.insert(method, (handler, MethodKind::Unary));
    }

    /// Register a server-streaming handler.
    fn add_server_stream_handler(&mut self, method: String, handler: Py<PyAny>) {
        self.handlers
            .insert(method, (handler, MethodKind::ServerStreaming));
    }

    /// Register a client-streaming handler.
    fn add_client_stream_handler(&mut self, method: String, handler: Py<PyAny>) {
        self.handlers
            .insert(method, (handler, MethodKind::ClientStreaming));
    }

    /// Register a bidi-streaming handler.
    fn add_bidi_stream_handler(&mut self, method: String, handler: Py<PyAny>) {
        self.handlers
            .insert(method, (handler, MethodKind::BidiStreaming));
    }
}

/// Bridge that implements the Rust `Service` trait by calling into Python.
pub(crate) struct PythonServiceBridge {
    pub(crate) name: String,
    pub(crate) handlers: HashMap<String, (Py<PyAny>, MethodKind)>,
}

impl PythonServiceBridge {
    pub fn from_handler(handler: &PyServiceHandler) -> Self {
        let handlers = Python::attach(|py| {
            handler
                .handlers
                .iter()
                .map(|(k, (obj, kind))| (k.clone(), (obj.clone_ref(py), *kind)))
                .collect()
        });
        Self {
            name: handler.name.clone(),
            handlers,
        }
    }
}

#[async_trait]
impl Service for PythonServiceBridge {
    fn name(&self) -> &str {
        &self.name
    }

    fn methods(&self) -> Vec<MethodDescriptor> {
        self.handlers
            .iter()
            .map(|(name, (_, kind))| MethodDescriptor {
                name: name.clone(),
                kind: *kind,
            })
            .collect()
    }

    async fn call_unary(
        &self,
        method: &str,
        request: RpcRequest,
    ) -> Result<RpcResponse, KnafehError> {
        let (handler, _) = self
            .handlers
            .get(method)
            .ok_or_else(|| KnafehError::Service {
                code: RpcStatusCode::NotFound,
                message: format!("method not found: {method}"),
            })?;

        let handler = Python::attach(|py| handler.clone_ref(py));
        let body = request.body;

        let result: Vec<u8> = tokio::task::spawn_blocking(move || {
            Python::attach(|py| {
                let py_bytes = PyBytes::new(py, &body);
                let result = handler
                    .call1(py, (py_bytes,))
                    .map_err(|e| KnafehError::Service {
                        code: RpcStatusCode::Internal,
                        message: format!("Python handler error: {e}"),
                    })?;

                let bytes: &Bound<PyBytes> =
                    result.cast_bound(py).map_err(|e| KnafehError::Service {
                        code: RpcStatusCode::Internal,
                        message: format!("handler must return bytes: {e}"),
                    })?;
                Ok::<Vec<u8>, KnafehError>(bytes.as_bytes().to_vec())
            })
        })
        .await
        .map_err(|e| KnafehError::Service {
            code: RpcStatusCode::Internal,
            message: format!("task join error: {e}"),
        })??;

        Ok(RpcResponse::ok(result))
    }

    async fn call_server_stream(
        &self,
        _method: &str,
        _request: RpcRequest,
    ) -> Result<RpcStreamResponse, KnafehError> {
        Err(KnafehError::Service {
            code: RpcStatusCode::Unimplemented,
            message: "server streaming not yet implemented in Python bridge".to_string(),
        })
    }

    async fn call_client_stream(
        &self,
        _method: &str,
        _stream: RpcStreamRequest,
    ) -> Result<RpcResponse, KnafehError> {
        Err(KnafehError::Service {
            code: RpcStatusCode::Unimplemented,
            message: "client streaming not yet implemented in Python bridge".to_string(),
        })
    }

    async fn call_bidi_stream(
        &self,
        _method: &str,
        _stream: RpcStreamRequest,
    ) -> Result<RpcStreamResponse, KnafehError> {
        Err(KnafehError::Service {
            code: RpcStatusCode::Unimplemented,
            message: "bidi streaming not yet implemented in Python bridge".to_string(),
        })
    }
}