code_analyze_mcp/
metrics.rs

1//! Metrics collection and daily-rotating JSONL emission.
2//!
3//! Provides a channel-based pipeline: callers emit [`MetricEvent`] values via [`MetricsSender`],
4//! and [`MetricsWriter`] drains the channel and appends events to a daily-rotated JSONL file
5//! under the XDG data directory (`~/.local/share/code-analyze-mcp/metrics-YYYY-MM-DD.jsonl`).
6//! Files older than 30 days are deleted on startup.
7
8use serde::{Deserialize, Serialize};
9use std::path::{Path, PathBuf};
10use std::time::{SystemTime, UNIX_EPOCH};
11use tokio::io::AsyncWriteExt;
12use tokio::sync::mpsc;
13
14/// A single metric event emitted by a tool invocation.
15#[derive(Debug, Clone, Serialize, Deserialize)]
16pub struct MetricEvent {
17    pub ts: u64,
18    pub tool: &'static str,
19    pub duration_ms: u64,
20    pub output_chars: usize,
21    pub param_path_depth: usize,
22    pub max_depth: Option<u32>,
23    pub result: &'static str,
24    pub error_type: Option<String>,
25    #[serde(default)]
26    pub session_id: Option<String>,
27    #[serde(default)]
28    pub seq: Option<u32>,
29}
30
31/// Sender half of the metrics channel; cloned and passed to tools for event emission.
32#[derive(Clone)]
33pub struct MetricsSender(pub tokio::sync::mpsc::UnboundedSender<MetricEvent>);
34
35impl MetricsSender {
36    pub fn send(&self, event: MetricEvent) {
37        let _ = self.0.send(event);
38    }
39}
40
41/// Receiver half of the metrics channel; drains events and writes them to daily-rotated JSONL files.
42pub struct MetricsWriter {
43    rx: tokio::sync::mpsc::UnboundedReceiver<MetricEvent>,
44    base_dir: PathBuf,
45}
46
47impl MetricsWriter {
48    pub fn new(
49        rx: tokio::sync::mpsc::UnboundedReceiver<MetricEvent>,
50        base_dir: Option<PathBuf>,
51    ) -> Self {
52        let dir = base_dir.unwrap_or_else(xdg_metrics_dir);
53        cleanup_old_files(&dir);
54        Self { rx, base_dir: dir }
55    }
56
57    pub async fn run(mut self) {
58        let mut current_date = current_date_str();
59        let mut current_file: Option<PathBuf> = None;
60
61        loop {
62            let mut batch = Vec::new();
63            if let Some(event) = self.rx.recv().await {
64                batch.push(event);
65                for _ in 0..99 {
66                    match self.rx.try_recv() {
67                        Ok(e) => batch.push(e),
68                        Err(mpsc::error::TryRecvError::Empty) => break,
69                        Err(mpsc::error::TryRecvError::Disconnected) => break,
70                    }
71                }
72            } else {
73                break;
74            }
75
76            let new_date = current_date_str();
77            if new_date != current_date {
78                current_date = new_date;
79                current_file = None;
80            }
81
82            if current_file.is_none() {
83                current_file = Some(rotate_path(&self.base_dir, &current_date));
84            }
85
86            let path = current_file.as_ref().unwrap();
87
88            // Create directory once per batch
89            if let Some(parent) = path.parent()
90                && !parent.as_os_str().is_empty()
91            {
92                tokio::fs::create_dir_all(parent).await.ok();
93            }
94
95            // Open file once per batch
96            let file = tokio::fs::OpenOptions::new()
97                .create(true)
98                .append(true)
99                .open(path)
100                .await;
101
102            if let Ok(mut file) = file {
103                for event in batch {
104                    if let Ok(json) = serde_json::to_string(&event) {
105                        let _ = file.write_all(json.as_bytes()).await;
106                        let _ = file.write_all(b"\n").await;
107                    }
108                }
109            }
110        }
111    }
112}
113
114/// Returns the current UNIX timestamp in milliseconds.
115pub fn unix_ms() -> u64 {
116    SystemTime::now()
117        .duration_since(UNIX_EPOCH)
118        .unwrap_or_default()
119        .as_millis() as u64
120}
121
122/// Counts the number of path segments in a file path.
123pub fn path_component_count(path: &str) -> usize {
124    Path::new(path).components().count()
125}
126
127/// Maps an MCP error code to a short string representation for metrics.
128pub fn error_code_to_type(code: rmcp::model::ErrorCode) -> &'static str {
129    match code {
130        rmcp::model::ErrorCode::PARSE_ERROR => "parse",
131        rmcp::model::ErrorCode::INVALID_PARAMS => "invalid_params",
132        rmcp::model::ErrorCode::METHOD_NOT_FOUND => "unknown",
133        rmcp::model::ErrorCode::INTERNAL_ERROR => "unknown",
134        _ => "unknown",
135    }
136}
137
138fn xdg_metrics_dir() -> PathBuf {
139    if let Ok(xdg_data_home) = std::env::var("XDG_DATA_HOME")
140        && !xdg_data_home.is_empty()
141    {
142        return PathBuf::from(xdg_data_home).join("code-analyze-mcp");
143    }
144
145    if let Ok(home) = std::env::var("HOME") {
146        PathBuf::from(home)
147            .join(".local")
148            .join("share")
149            .join("code-analyze-mcp")
150    } else {
151        PathBuf::from(".")
152    }
153}
154
155fn rotate_path(base_dir: &Path, date_str: &str) -> PathBuf {
156    base_dir.join(format!("metrics-{}.jsonl", date_str))
157}
158
159fn cleanup_old_files(base_dir: &Path) {
160    let now_days = (unix_ms() / 86_400_000) as u32;
161
162    let Ok(entries) = std::fs::read_dir(base_dir) else {
163        return;
164    };
165
166    for entry in entries.flatten() {
167        let path = entry.path();
168        let file_name = match path.file_name() {
169            Some(n) => n.to_string_lossy().into_owned(),
170            None => continue,
171        };
172
173        // Expected format: metrics-YYYY-MM-DD.jsonl
174        if !file_name.starts_with("metrics-") || !file_name.ends_with(".jsonl") {
175            continue;
176        }
177        let date_part = &file_name[8..file_name.len() - 6];
178        if date_part.len() != 10
179            || date_part.as_bytes().get(4) != Some(&b'-')
180            || date_part.as_bytes().get(7) != Some(&b'-')
181        {
182            continue;
183        }
184        let Ok(year) = date_part[0..4].parse::<u32>() else {
185            continue;
186        };
187        let Ok(month) = date_part[5..7].parse::<u32>() else {
188            continue;
189        };
190        let Ok(day) = date_part[8..10].parse::<u32>() else {
191            continue;
192        };
193        if month == 0 || month > 12 || day == 0 || day > 31 {
194            continue;
195        }
196
197        let file_days = date_to_days_since_epoch(year, month, day);
198        if now_days > file_days && (now_days - file_days) > 30 {
199            let _ = std::fs::remove_file(&path);
200        }
201    }
202}
203
204fn date_to_days_since_epoch(y: u32, m: u32, d: u32) -> u32 {
205    // Shift year so March is month 0
206    let (y, m) = if m <= 2 { (y - 1, m + 9) } else { (y, m - 3) };
207    let era = y / 400;
208    let yoe = y - era * 400;
209    let doy = (153 * m + 2) / 5 + d - 1;
210    let doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
211    era * 146_097
212        + doe // this is the Proleptic Gregorian day number
213            .saturating_sub(719_468) // subtract the epoch offset to get days since 1970-01-01
214}
215
216/// Returns the current UTC date as a string in YYYY-MM-DD format.
217pub fn current_date_str() -> String {
218    let days = (unix_ms() / 86_400_000) as u32;
219    let z = days + 719_468;
220    let era = z / 146_097;
221    let doe = z - era * 146_097;
222    let yoe = (doe - doe / 1460 + doe / 36524 - doe / 146_096) / 365;
223    let y = yoe + era * 400;
224    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
225    let mp = (5 * doy + 2) / 153;
226    let d = doy - (153 * mp + 2) / 5 + 1;
227    let m = if mp < 10 { mp + 3 } else { mp - 9 };
228    let y = if m <= 2 { y + 1 } else { y };
229    format!("{:04}-{:02}-{:02}", y, m, d)
230}
231
232#[cfg(test)]
233mod tests {
234    use super::*;
235
236    #[test]
237    fn test_metric_event_serialization() {
238        let event = MetricEvent {
239            ts: 1_700_000_000_000,
240            tool: "analyze_directory",
241            duration_ms: 42,
242            output_chars: 100,
243            param_path_depth: 3,
244            max_depth: Some(2),
245            result: "ok",
246            error_type: None,
247            session_id: None,
248            seq: None,
249        };
250        let json = serde_json::to_string(&event).unwrap();
251        assert!(json.contains("analyze_directory"));
252        assert!(json.contains(r#""result":"ok""#));
253        assert!(json.contains(r#""output_chars":100"#));
254    }
255
256    #[test]
257    fn test_metric_event_serialization_error() {
258        let event = MetricEvent {
259            ts: 1_700_000_000_000,
260            tool: "analyze_directory",
261            duration_ms: 5,
262            output_chars: 0,
263            param_path_depth: 3,
264            max_depth: Some(3),
265            result: "error",
266            error_type: Some("invalid_params".to_string()),
267            session_id: None,
268            seq: None,
269        };
270        let json = serde_json::to_string(&event).unwrap();
271        assert!(json.contains(r#""result":"error""#));
272        assert!(json.contains(r#""error_type":"invalid_params""#));
273        assert!(json.contains(r#""output_chars":0"#));
274        assert!(json.contains(r#""max_depth":3"#));
275    }
276
277    #[test]
278    fn test_metric_event_new_fields_round_trip() {
279        let event = MetricEvent {
280            ts: 1_700_000_000_000,
281            tool: "analyze_file",
282            duration_ms: 100,
283            output_chars: 500,
284            param_path_depth: 2,
285            max_depth: Some(3),
286            result: "ok",
287            error_type: None,
288            session_id: Some("1742468880123-42".to_string()),
289            seq: Some(5),
290        };
291        let serialized = serde_json::to_string(&event).unwrap();
292        let json_str = r#"{"ts":1700000000000,"tool":"analyze_file","duration_ms":100,"output_chars":500,"param_path_depth":2,"max_depth":3,"result":"ok","error_type":null,"session_id":"1742468880123-42","seq":5}"#;
293        assert_eq!(serialized, json_str);
294        let parsed: MetricEvent = serde_json::from_str(json_str).unwrap();
295        assert_eq!(parsed.session_id, Some("1742468880123-42".to_string()));
296        assert_eq!(parsed.seq, Some(5));
297    }
298
299    #[test]
300    fn test_metric_event_backward_compat_parse() {
301        let old_jsonl = r#"{"ts":1700000000000,"tool":"analyze_directory","duration_ms":42,"output_chars":100,"param_path_depth":3,"max_depth":2,"result":"ok","error_type":null}"#;
302        let parsed: MetricEvent = serde_json::from_str(old_jsonl).unwrap();
303        assert_eq!(parsed.tool, "analyze_directory");
304        assert_eq!(parsed.session_id, None);
305        assert_eq!(parsed.seq, None);
306    }
307
308    #[test]
309    fn test_session_id_format() {
310        let event = MetricEvent {
311            ts: 1_700_000_000_000,
312            tool: "analyze_symbol",
313            duration_ms: 20,
314            output_chars: 50,
315            param_path_depth: 1,
316            max_depth: None,
317            result: "ok",
318            error_type: None,
319            session_id: Some("1742468880123-0".to_string()),
320            seq: Some(0),
321        };
322        let sid = event.session_id.unwrap();
323        assert!(sid.contains('-'), "session_id should contain a dash");
324        let parts: Vec<&str> = sid.split('-').collect();
325        assert_eq!(parts.len(), 2, "session_id should have exactly 2 parts");
326        assert!(parts[0].len() == 13, "millis part should be 13 digits");
327    }
328}
code_analyze_mcp/metrics.rs

code_analyze_mcp/
metrics.rs
