opendata-log 0.2.2

Key-oriented log database built on SlateDB
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
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348

//! HTTP middleware for Axum.

use std::future::Future;
use std::pin::Pin;
use std::sync::Arc;
use std::task::{Context, Poll};
use std::time::Instant;

use axum::body::Body;
use axum::http::{Request, Response};
use tower::{Layer, Service};

use super::metrics::{HttpLabels, HttpLabelsWithStatus, HttpMethod, Metrics};

/// RAII guard that decrements the in-flight gauge on drop, ensuring the gauge
/// is always decremented even if the request future is cancelled or errors.
struct InFlightGuard {
    metrics: Arc<Metrics>,
}

impl Drop for InFlightGuard {
    fn drop(&mut self) {
        self.metrics.http_requests_in_flight.dec();
    }
}

/// Layer that wraps services with metrics collection.
#[derive(Clone)]
pub struct MetricsLayer {
    metrics: Arc<Metrics>,
}

impl MetricsLayer {
    pub fn new(metrics: Arc<Metrics>) -> Self {
        Self { metrics }
    }
}

impl<S> Layer<S> for MetricsLayer {
    type Service = MetricsService<S>;

    fn layer(&self, inner: S) -> Self::Service {
        MetricsService {
            inner,
            metrics: self.metrics.clone(),
        }
    }
}

/// Service that collects HTTP metrics.
#[derive(Clone)]
pub struct MetricsService<S> {
    inner: S,
    metrics: Arc<Metrics>,
}

impl<S, ResBody> Service<Request<Body>> for MetricsService<S>
where
    S: Service<Request<Body>, Response = Response<ResBody>> + Clone + Send + 'static,
    S::Future: Send,
    ResBody: Send,
{
    type Response = S::Response;
    type Error = S::Error;
    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;

    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        self.inner.poll_ready(cx)
    }

    fn call(&mut self, request: Request<Body>) -> Self::Future {
        let method = HttpMethod::from(request.method());
        let endpoint = normalize_endpoint(request.uri().path());
        let metrics = self.metrics.clone();

        metrics.http_requests_in_flight.inc();
        let _guard = InFlightGuard {
            metrics: metrics.clone(),
        };
        let start = Instant::now();
        let future = self.inner.call(request);

        Box::pin(async move {
            let _guard = _guard; // move guard into the future so it drops when the future completes
            let response = future.await?;
            let status = response.status().as_u16();
            let duration = start.elapsed().as_secs_f64();

            // Record request count
            metrics
                .http_requests_total
                .get_or_create(&HttpLabelsWithStatus {
                    method: method.clone(),
                    endpoint: endpoint.clone(),
                    status,
                })
                .inc();

            // Record request latency
            metrics
                .http_request_duration_seconds
                .get_or_create(&HttpLabels { method, endpoint })
                .observe(duration);

            Ok(response)
        })
    }
}

/// Normalize endpoint paths to avoid high cardinality.
fn normalize_endpoint(path: &str) -> String {
    path.to_string()
}

/// Layer that wraps services with request tracing.
#[derive(Clone)]
pub struct TracingLayer;

impl TracingLayer {
    pub fn new() -> Self {
        Self
    }
}

impl Default for TracingLayer {
    fn default() -> Self {
        Self::new()
    }
}

impl<S> Layer<S> for TracingLayer {
    type Service = TracingService<S>;

    fn layer(&self, inner: S) -> Self::Service {
        TracingService { inner }
    }
}

/// Service that logs HTTP requests and responses at debug level.
#[derive(Clone)]
pub struct TracingService<S> {
    inner: S,
}

impl<S, ResBody> Service<Request<Body>> for TracingService<S>
where
    S: Service<Request<Body>, Response = Response<ResBody>> + Clone + Send + 'static,
    S::Future: Send,
    ResBody: Send,
{
    type Response = S::Response;
    type Error = S::Error;
    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;

    fn poll_ready(&mut self, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        self.inner.poll_ready(cx)
    }

    fn call(&mut self, request: Request<Body>) -> Self::Future {
        // Extract request details for logging
        let http_method = request.method().clone();
        let uri = request.uri().clone();
        let user_agent = request
            .headers()
            .get("user-agent")
            .and_then(|v| v.to_str().ok())
            .unwrap_or("-");
        let content_length = request
            .headers()
            .get("content-length")
            .and_then(|v| v.to_str().ok())
            .unwrap_or("-");

        // Log request details
        tracing::debug!(
            method = %http_method,
            uri = %uri,
            user_agent = %user_agent,
            content_length = %content_length,
            "HTTP request received"
        );

        let start_time = Instant::now();
        let future = self.inner.call(request);

        Box::pin(async move {
            let response = future.await?;
            let status = response.status().as_u16();
            let elapsed = start_time.elapsed();

            // Log response details
            tracing::debug!(
                method = %http_method,
                uri = %uri,
                status = %status,
                duration_ms = %elapsed.as_millis(),
                "HTTP request completed"
            );

            Ok(response)
        })
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use axum::http::Method;
    use tower::service_fn;

    fn test_request(uri: &str) -> Request<Body> {
        Request::builder()
            .method(Method::GET)
            .uri(uri)
            .body(Body::empty())
            .unwrap()
    }

    #[tokio::test]
    async fn should_decrement_in_flight_gauge_after_successful_request() {
        // given
        let metrics = Arc::new(Metrics::new());
        let mut service = MetricsService {
            inner: service_fn(|_req: Request<Body>| async {
                Ok::<_, std::convert::Infallible>(
                    Response::builder().status(200).body(Body::empty()).unwrap(),
                )
            }),
            metrics: metrics.clone(),
        };

        assert_eq!(metrics.http_requests_in_flight.get(), 0);

        // when
        let future = service.call(test_request("/test"));
        assert_eq!(metrics.http_requests_in_flight.get(), 1);
        let response = future.await.unwrap();

        // then
        assert_eq!(response.status().as_u16(), 200);
        assert_eq!(metrics.http_requests_in_flight.get(), 0);
    }

    #[tokio::test]
    async fn should_decrement_in_flight_gauge_when_inner_service_errors() {
        // given
        let metrics = Arc::new(Metrics::new());
        let mut service = MetricsService {
            inner: service_fn(|_req: Request<Body>| async {
                Err::<Response<Body>, _>(std::io::Error::new(
                    std::io::ErrorKind::ConnectionReset,
                    "connection reset",
                ))
            }),
            metrics: metrics.clone(),
        };

        assert_eq!(metrics.http_requests_in_flight.get(), 0);

        // when
        let future = service.call(test_request("/test"));
        assert_eq!(metrics.http_requests_in_flight.get(), 1);
        let result = future.await;

        // then
        assert!(result.is_err());
        assert_eq!(metrics.http_requests_in_flight.get(), 0);
    }

    #[tokio::test]
    async fn should_decrement_in_flight_gauge_when_future_is_cancelled() {
        // given — a service that never completes (simulates a long-poll)
        let metrics = Arc::new(Metrics::new());
        let mut service = MetricsService {
            inner: service_fn(|_req: Request<Body>| {
                std::future::pending::<Result<Response<Body>, std::convert::Infallible>>()
            }),
            metrics: metrics.clone(),
        };

        assert_eq!(metrics.http_requests_in_flight.get(), 0);

        // when — call returns a future (gauge incremented), then drop it
        let future = service.call(test_request("/api/v1/log/scan"));
        assert_eq!(metrics.http_requests_in_flight.get(), 1);

        drop(future);

        // then — gauge must return to zero despite the future never completing
        assert_eq!(metrics.http_requests_in_flight.get(), 0);
    }

    #[test]
    fn should_preserve_api_endpoints() {
        // given
        let path = "/api/v1/log/scan";

        // when
        let normalized = normalize_endpoint(path);

        // then
        assert_eq!(normalized, "/api/v1/log/scan");
    }

    #[test]
    fn should_preserve_metrics_endpoint() {
        // given
        let path = "/metrics";

        // when
        let normalized = normalize_endpoint(path);

        // then
        assert_eq!(normalized, "/metrics");
    }

    #[tokio::test]
    async fn should_log_request_and_response_with_tracing_middleware() {
        use tower::service_fn;

        // Create a simple test service that returns 200 OK
        let test_service = service_fn(|_req: Request<Body>| async {
            Ok::<_, std::convert::Infallible>(
                Response::builder().status(200).body(Body::empty()).unwrap(),
            )
        });

        // Wrap with tracing middleware
        let mut service = TracingService {
            inner: test_service,
        };

        // Create test request
        let request = Request::builder()
            .method(Method::GET)
            .uri("/api/v1/log/scan?key=test")
            .header("user-agent", "test-client")
            .header("content-length", "0")
            .body(Body::empty())
            .unwrap();

        // Call the service - this should log the request and response
        let response = service.call(request).await.unwrap();

        // Verify response
        assert_eq!(response.status().as_u16(), 200);
    }
}