structured-proxy 1.0.1

Universal gRPC→REST transcoding proxy — config-driven, works with any gRPC service
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

//! gRPC → HTTP error mapping.
//!
//! Converts `tonic::Status` to appropriate HTTP status codes and JSON error bodies
//! following the gRPC-HTTP status code mapping from the gRPC specification.

use axum::http::StatusCode;
use axum::response::{IntoResponse, Response};
use axum::Json;

/// Map a gRPC status code to the corresponding HTTP status code.
///
/// Based on <https://github.com/grpc/grpc/blob/master/doc/http-grpc-status-mapping.md>
pub fn grpc_to_http_status(code: tonic::Code) -> StatusCode {
    match code {
        tonic::Code::Ok => StatusCode::OK,
        tonic::Code::Cancelled => StatusCode::from_u16(499).unwrap_or(StatusCode::BAD_REQUEST),
        tonic::Code::Unknown => StatusCode::INTERNAL_SERVER_ERROR,
        tonic::Code::InvalidArgument => StatusCode::BAD_REQUEST,
        tonic::Code::DeadlineExceeded => StatusCode::GATEWAY_TIMEOUT,
        tonic::Code::NotFound => StatusCode::NOT_FOUND,
        tonic::Code::AlreadyExists => StatusCode::CONFLICT,
        tonic::Code::PermissionDenied => StatusCode::FORBIDDEN,
        tonic::Code::ResourceExhausted => StatusCode::TOO_MANY_REQUESTS,
        tonic::Code::FailedPrecondition => StatusCode::BAD_REQUEST,
        tonic::Code::Aborted => StatusCode::CONFLICT,
        tonic::Code::OutOfRange => StatusCode::BAD_REQUEST,
        tonic::Code::Unimplemented => StatusCode::NOT_IMPLEMENTED,
        tonic::Code::Internal => StatusCode::INTERNAL_SERVER_ERROR,
        tonic::Code::Unavailable => StatusCode::SERVICE_UNAVAILABLE,
        tonic::Code::DataLoss => StatusCode::INTERNAL_SERVER_ERROR,
        tonic::Code::Unauthenticated => StatusCode::UNAUTHORIZED,
    }
}

/// Convert a `tonic::Status` into an axum HTTP response with JSON error body.
pub fn status_to_response(status: tonic::Status) -> Response {
    let http_status = grpc_to_http_status(status.code());
    let body = serde_json::json!({
        "error": grpc_code_name(status.code()),
        "message": status.message(),
        "code": status.code() as i32,
    });
    (http_status, Json(body)).into_response()
}

/// Human-readable gRPC code name for JSON error responses.
fn grpc_code_name(code: tonic::Code) -> &'static str {
    match code {
        tonic::Code::Ok => "OK",
        tonic::Code::Cancelled => "CANCELLED",
        tonic::Code::Unknown => "UNKNOWN",
        tonic::Code::InvalidArgument => "INVALID_ARGUMENT",
        tonic::Code::DeadlineExceeded => "DEADLINE_EXCEEDED",
        tonic::Code::NotFound => "NOT_FOUND",
        tonic::Code::AlreadyExists => "ALREADY_EXISTS",
        tonic::Code::PermissionDenied => "PERMISSION_DENIED",
        tonic::Code::ResourceExhausted => "RESOURCE_EXHAUSTED",
        tonic::Code::FailedPrecondition => "FAILED_PRECONDITION",
        tonic::Code::Aborted => "ABORTED",
        tonic::Code::OutOfRange => "OUT_OF_RANGE",
        tonic::Code::Unimplemented => "UNIMPLEMENTED",
        tonic::Code::Internal => "INTERNAL",
        tonic::Code::Unavailable => "UNAVAILABLE",
        tonic::Code::DataLoss => "DATA_LOSS",
        tonic::Code::Unauthenticated => "UNAUTHENTICATED",
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_grpc_to_http_mapping() {
        assert_eq!(grpc_to_http_status(tonic::Code::Ok), StatusCode::OK);
        assert_eq!(
            grpc_to_http_status(tonic::Code::InvalidArgument),
            StatusCode::BAD_REQUEST
        );
        assert_eq!(
            grpc_to_http_status(tonic::Code::NotFound),
            StatusCode::NOT_FOUND
        );
        assert_eq!(
            grpc_to_http_status(tonic::Code::AlreadyExists),
            StatusCode::CONFLICT
        );
        assert_eq!(
            grpc_to_http_status(tonic::Code::PermissionDenied),
            StatusCode::FORBIDDEN
        );
        assert_eq!(
            grpc_to_http_status(tonic::Code::Unauthenticated),
            StatusCode::UNAUTHORIZED
        );
        assert_eq!(
            grpc_to_http_status(tonic::Code::ResourceExhausted),
            StatusCode::TOO_MANY_REQUESTS
        );
        assert_eq!(
            grpc_to_http_status(tonic::Code::Unimplemented),
            StatusCode::NOT_IMPLEMENTED
        );
        assert_eq!(
            grpc_to_http_status(tonic::Code::Internal),
            StatusCode::INTERNAL_SERVER_ERROR
        );
        assert_eq!(
            grpc_to_http_status(tonic::Code::Unavailable),
            StatusCode::SERVICE_UNAVAILABLE
        );
        assert_eq!(
            grpc_to_http_status(tonic::Code::DeadlineExceeded),
            StatusCode::GATEWAY_TIMEOUT
        );
    }

    #[test]
    fn test_grpc_code_name() {
        assert_eq!(grpc_code_name(tonic::Code::Ok), "OK");
        assert_eq!(grpc_code_name(tonic::Code::NotFound), "NOT_FOUND");
        assert_eq!(
            grpc_code_name(tonic::Code::Unauthenticated),
            "UNAUTHENTICATED"
        );
    }

    #[test]
    fn test_status_to_response() {
        let status = tonic::Status::not_found("user not found");
        let response = status_to_response(status);
        assert_eq!(response.status(), StatusCode::NOT_FOUND);
    }
}