kegani 0.1.1

A developer-friendly, ergonomic, production-ready Rust web framework
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

//! Metrics recorder for Kegani
//!
//! Provides Prometheus-compatible metrics.

use std::sync::Arc;
use tokio::sync::RwLock;
use std::collections::HashMap;
use std::time::Duration;

/// Metrics recorder
#[derive(Clone)]
pub struct Metrics {
    counters: Arc<RwLock<HashMap<String, Counter>>>,
    gauges: Arc<RwLock<HashMap<String, Gauge>>>,
    histograms: Arc<RwLock<HashMap<String, Histogram>>>,
}

impl Metrics {
    /// Create a new metrics recorder
    pub fn new() -> Self {
        Self {
            counters: Arc::new(RwLock::new(HashMap::new())),
            gauges: Arc::new(RwLock::new(HashMap::new())),
            histograms: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    /// Get or create a counter
    pub async fn counter(&self, name: &str) -> Counter {
        let mut counters = self.counters.write().await;
        counters
            .entry(name.to_string())
            .or_insert_with(Counter::new)
            .clone()
    }

    /// Get or create a gauge
    pub async fn gauge(&self, name: &str) -> Gauge {
        let mut gauges = self.gauges.write().await;
        gauges
            .entry(name.to_string())
            .or_insert_with(Gauge::new)
            .clone()
    }

    /// Get or create a histogram
    pub async fn histogram(&self, name: &str) -> Histogram {
        let mut histograms = self.histograms.write().await;
        histograms
            .entry(name.to_string())
            .or_insert_with(Histogram::new)
            .clone()
    }

    /// Increment HTTP requests counter
    pub async fn inc_http_requests(&self, method: &str, path: &str, status: u16) {
        let counter = self.counter("http_requests_total").await;
        counter.inc_by(1.0, &[("method", method), ("path", path), ("status", &status.to_string())]).await;
    }

    /// Record HTTP request duration
    pub async fn observe_http_duration(&self, method: &str, path: &str, duration: Duration) {
        let histogram = self.histogram("http_request_duration_seconds").await;
        histogram.observe(duration.as_secs_f64(), &[("method", method), ("path", path)]).await;
    }

    /// Set active connections gauge
    pub async fn set_active_connections(&self, count: usize) {
        let gauge = self.gauge("active_connections").await;
        gauge.set(count as f64, &[]).await;
    }

    /// Export metrics in Prometheus format
    pub async fn export(&self) -> String {
        let mut output = String::new();

        // Export counters
        let counters = self.counters.read().await;
        for (name, counter) in counters.iter() {
            output.push_str(&format!("# HELP {} {}\n", name, name));
            output.push_str(&format!("# TYPE {} counter\n", name));
            for (labels, value) in counter.get_values().await {
                output.push_str(&format!("{}{} {}\n", name, labels, value));
            }
        }

        // Export gauges
        let gauges = self.gauges.read().await;
        for (name, gauge) in gauges.iter() {
            output.push_str(&format!("# HELP {} {}\n", name, name));
            output.push_str(&format!("# TYPE {} gauge\n", name));
            for (labels, value) in gauge.get_values().await {
                output.push_str(&format!("{}{} {}\n", name, labels, value));
            }
        }

        // Export histograms
        let histograms = self.histograms.read().await;
        for (name, histogram) in histograms.iter() {
            output.push_str(&format!("# HELP {} {}\n", name, name));
            output.push_str(&format!("# TYPE {} histogram\n", name));
            for (labels, bucket_data) in histogram.get_buckets().await {
                let bucket_name = format!("{}_bucket", name);
                for data in bucket_data {
                    output.push_str(&format!("{}{{{}le=\"{}\"}} {}\n", bucket_name, labels, data.le, data.count));
                }
            }
            output.push_str(&format!("{}_sum{} {}\n", name, "", histogram.get_sum().await));
            output.push_str(&format!("{}_count{} {}\n", name, "", histogram.get_count().await));
        }

        output
    }
}

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

/// Counter metric
#[derive(Clone)]
pub struct Counter {
    values: Arc<RwLock<HashMap<String, f64>>>,
    labels: Arc<RwLock<HashMap<String, Vec<(String, String)>>>>,
}

impl Counter {
    pub fn new() -> Self {
        Self {
            values: Arc::new(RwLock::new(HashMap::new())),
            labels: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    pub async fn inc(&self, labels: &[(&str, &str)]) {
        let key = Self::labels_to_key(labels);
        let mut values = self.values.write().await;
        *values.entry(key.clone()).or_insert(0.0) += 1.0;

        let mut all_labels = self.labels.write().await;
        all_labels.insert(key, labels.iter().map(|(k, v)| (k.to_string(), v.to_string())).collect());
    }

    pub async fn inc_by(&self, value: f64, labels: &[(&str, &str)]) {
        let key = Self::labels_to_key(labels);
        let mut values = self.values.write().await;
        *values.entry(key.clone()).or_insert(0.0) += value;

        let mut all_labels = self.labels.write().await;
        all_labels.insert(key, labels.iter().map(|(k, v)| (k.to_string(), v.to_string())).collect());
    }

    pub async fn get_values(&self) -> Vec<(String, f64)> {
        let values = self.values.read().await;
        let labels = self.labels.read().await;

        values
            .iter()
            .map(|(k, v)| {
                let label_str = labels.get(k)
                    .map(|l| l.iter().map(|(k, v)| format!("{}=\"{}\"", k, v)).collect::<Vec<_>>().join(","))
                    .unwrap_or_default();
                (format!("{{{}}}", label_str), *v)
            })
            .collect()
    }

    fn labels_to_key(labels: &[(&str, &str)]) -> String {
        labels.iter().map(|(k, v)| format!("{}={}", k, v)).collect::<Vec<_>>().join(",")
    }
}

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

/// Gauge metric
#[derive(Clone)]
pub struct Gauge {
    values: Arc<RwLock<HashMap<String, f64>>>,
    labels: Arc<RwLock<HashMap<String, Vec<(String, String)>>>>,
}

impl Gauge {
    pub fn new() -> Self {
        Self {
            values: Arc::new(RwLock::new(HashMap::new())),
            labels: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    pub async fn set(&self, value: f64, labels: &[(&str, &str)]) {
        let key = Self::labels_to_key(labels);
        let mut values = self.values.write().await;
        values.insert(key.clone(), value);

        let mut all_labels = self.labels.write().await;
        all_labels.insert(key, labels.iter().map(|(k, v)| (k.to_string(), v.to_string())).collect());
    }

    pub async fn inc(&self, labels: &[(&str, &str)]) {
        let key = Self::labels_to_key(labels);
        let mut values = self.values.write().await;
        *values.entry(key.clone()).or_insert(0.0) += 1.0;
    }

    pub async fn dec(&self, labels: &[(&str, &str)]) {
        let key = Self::labels_to_key(labels);
        let mut values = self.values.write().await;
        *values.entry(key.clone()).or_insert(0.0) -= 1.0;
    }

    pub async fn get_values(&self) -> Vec<(String, f64)> {
        let values = self.values.read().await;
        let labels = self.labels.read().await;

        values
            .iter()
            .map(|(k, v)| {
                let label_str = labels.get(k)
                    .map(|l| l.iter().map(|(k, v)| format!("{}=\"{}\"", k, v)).collect::<Vec<_>>().join(","))
                    .unwrap_or_default();
                (format!("{{{}}}", label_str), *v)
            })
            .collect()
    }

    fn labels_to_key(labels: &[(&str, &str)]) -> String {
        labels.iter().map(|(k, v)| format!("{}={}", k, v)).collect::<Vec<_>>().join(",")
    }
}

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

/// Histogram metric
#[derive(Clone)]
pub struct Histogram {
    buckets: Arc<RwLock<HashMap<String, Vec<BucketData>>>>,
    sum: Arc<RwLock<HashMap<String, f64>>>,
    count: Arc<RwLock<HashMap<String, u64>>>,
}

#[derive(Debug, Clone)]
pub struct BucketData {
    le: f64,
    count: u64,
}

impl Histogram {
    pub fn new() -> Self {
        Self {
            buckets: Arc::new(RwLock::new(HashMap::new())),
            sum: Arc::new(RwLock::new(HashMap::new())),
            count: Arc::new(RwLock::new(HashMap::new())),
        }
    }

    pub async fn observe(&self, value: f64, labels: &[(&str, &str)]) {
        let key = Self::labels_to_key(labels);

        // Update sum
        let mut sum = self.sum.write().await;
        *sum.entry(key.clone()).or_insert(0.0) += value;

        // Update count
        let mut count = self.count.write().await;
        *count.entry(key.clone()).or_insert(0) += 1;

        // Update buckets
        let bucket_bounds = vec![0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1.0, 2.5, 5.0, 10.0];
        let mut buckets = self.buckets.write().await;

        for bound in bucket_bounds {
            if value <= bound {
                if let Some(bucket) = buckets.entry(key.clone()).or_insert_with(|| {
                    vec![BucketData { le: 0.005, count: 0 }; 11]
                }).iter_mut().find(|b| b.le == bound) {
                    bucket.count += 1;
                }
            }
        }
    }

    pub async fn get_buckets(&self) -> Vec<(String, Vec<BucketData>)> {
        let buckets = self.buckets.read().await;
        buckets.iter().map(|(k, v)| (k.clone(), v.clone())).collect()
    }

    pub async fn get_sum(&self) -> f64 {
        let sum = self.sum.read().await;
        sum.values().sum()
    }

    pub async fn get_count(&self) -> u64 {
        let count = self.count.read().await;
        count.values().sum()
    }

    fn labels_to_key(labels: &[(&str, &str)]) -> String {
        labels.iter().map(|(k, v)| format!("{}={}", k, v)).collect::<Vec<_>>().join(",")
    }
}

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