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        Self { rx, base_dir: dir }
54    }
55
56    pub async fn run(mut self) {
57        cleanup_old_files(&self.base_dir).await;
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(
69                            mpsc::error::TryRecvError::Empty
70                            | mpsc::error::TryRecvError::Disconnected,
71                        ) => break,
72                    }
73                }
74            } else {
75                break;
76            }
77
78            let new_date = current_date_str();
79            if new_date != current_date {
80                current_date = new_date;
81                current_file = None;
82            }
83
84            if current_file.is_none() {
85                current_file = Some(rotate_path(&self.base_dir, &current_date));
86            }
87
88            let path = current_file.as_ref().unwrap();
89
90            // Create directory once per batch
91            if let Some(parent) = path.parent()
92                && !parent.as_os_str().is_empty()
93            {
94                tokio::fs::create_dir_all(parent).await.ok();
95            }
96
97            // Open file once per batch
98            let file = tokio::fs::OpenOptions::new()
99                .create(true)
100                .append(true)
101                .open(path)
102                .await;
103
104            if let Ok(mut file) = file {
105                for event in batch {
106                    if let Ok(mut json) = serde_json::to_string(&event) {
107                        json.push('\n');
108                        let _ = file.write_all(json.as_bytes()).await;
109                    }
110                }
111                let _ = file.flush().await;
112            }
113        }
114    }
115}
116
117/// Returns the current UNIX timestamp in milliseconds.
118#[must_use]
119pub fn unix_ms() -> u64 {
120    SystemTime::now()
121        .duration_since(UNIX_EPOCH)
122        .unwrap_or_default()
123        .as_millis()
124        .try_into()
125        .unwrap_or(u64::MAX)
126}
127
128/// Counts the number of path segments in a file path.
129#[must_use]
130pub fn path_component_count(path: &str) -> usize {
131    Path::new(path).components().count()
132}
133
134/// Maps an MCP error code to a short string representation for metrics.
135#[must_use]
136pub fn error_code_to_type(code: rmcp::model::ErrorCode) -> &'static str {
137    match code {
138        rmcp::model::ErrorCode::PARSE_ERROR => "parse",
139        rmcp::model::ErrorCode::INVALID_PARAMS => "invalid_params",
140        _ => "unknown",
141    }
142}
143
144fn xdg_metrics_dir() -> PathBuf {
145    if let Ok(xdg_data_home) = std::env::var("XDG_DATA_HOME")
146        && !xdg_data_home.is_empty()
147    {
148        return PathBuf::from(xdg_data_home).join("code-analyze-mcp");
149    }
150
151    if let Ok(home) = std::env::var("HOME") {
152        PathBuf::from(home)
153            .join(".local")
154            .join("share")
155            .join("code-analyze-mcp")
156    } else {
157        PathBuf::from(".")
158    }
159}
160
161fn rotate_path(base_dir: &Path, date_str: &str) -> PathBuf {
162    base_dir.join(format!("metrics-{date_str}.jsonl"))
163}
164
165async fn cleanup_old_files(base_dir: &Path) {
166    let now_days = u32::try_from(unix_ms() / 86_400_000).unwrap_or(u32::MAX);
167
168    let Ok(mut entries) = tokio::fs::read_dir(base_dir).await else {
169        return;
170    };
171
172    loop {
173        match entries.next_entry().await {
174            Ok(Some(entry)) => {
175                let path = entry.path();
176                let file_name = match path.file_name() {
177                    Some(n) => n.to_string_lossy().into_owned(),
178                    None => continue,
179                };
180
181                // Expected format: metrics-YYYY-MM-DD.jsonl
182                if !file_name.starts_with("metrics-")
183                    || std::path::Path::new(&*file_name)
184                        .extension()
185                        .is_none_or(|e| !e.eq_ignore_ascii_case("jsonl"))
186                {
187                    continue;
188                }
189                let date_part = &file_name[8..file_name.len() - 6];
190                if date_part.len() != 10
191                    || date_part.as_bytes().get(4) != Some(&b'-')
192                    || date_part.as_bytes().get(7) != Some(&b'-')
193                {
194                    continue;
195                }
196                let Ok(year) = date_part[0..4].parse::<u32>() else {
197                    continue;
198                };
199                let Ok(month) = date_part[5..7].parse::<u32>() else {
200                    continue;
201                };
202                let Ok(day) = date_part[8..10].parse::<u32>() else {
203                    continue;
204                };
205                if month == 0 || month > 12 || day == 0 || day > 31 {
206                    continue;
207                }
208
209                let file_days = date_to_days_since_epoch(year, month, day);
210                if now_days > file_days && (now_days - file_days) > 30 {
211                    let _ = tokio::fs::remove_file(&path).await;
212                }
213            }
214            Ok(None) => break,
215            Err(e) => {
216                tracing::warn!("error reading metrics directory entry: {e}");
217            }
218        }
219    }
220}
221
222fn date_to_days_since_epoch(y: u32, m: u32, d: u32) -> u32 {
223    // Shift year so March is month 0
224    let (y, m) = if m <= 2 { (y - 1, m + 9) } else { (y, m - 3) };
225    let era = y / 400;
226    let yoe = y - era * 400;
227    let doy = (153 * m + 2) / 5 + d - 1;
228    let doe = yoe * 365 + yoe / 4 - yoe / 100 + doy;
229    era * 146_097
230        + doe // this is the Proleptic Gregorian day number
231            .saturating_sub(719_468) // subtract the epoch offset to get days since 1970-01-01
232}
233
234/// Returns the current UTC date as a string in YYYY-MM-DD format.
235#[must_use]
236pub fn current_date_str() -> String {
237    let days = u32::try_from(unix_ms() / 86_400_000).unwrap_or(u32::MAX);
238    let z = days + 719_468;
239    let era = z / 146_097;
240    let doe = z - era * 146_097;
241    let yoe = (doe - doe / 1460 + doe / 36524 - doe / 146_096) / 365;
242    let y = yoe + era * 400;
243    let doy = doe - (365 * yoe + yoe / 4 - yoe / 100);
244    let mp = (5 * doy + 2) / 153;
245    let d = doy - (153 * mp + 2) / 5 + 1;
246    let m = if mp < 10 { mp + 3 } else { mp - 9 };
247    let y = if m <= 2 { y + 1 } else { y };
248    format!("{y:04}-{m:02}-{d:02}")
249}
250
251#[cfg(test)]
252mod tests {
253    use super::*;
254
255    #[test]
256    fn test_metric_event_serialization() {
257        let event = MetricEvent {
258            ts: 1_700_000_000_000,
259            tool: "analyze_directory",
260            duration_ms: 42,
261            output_chars: 100,
262            param_path_depth: 3,
263            max_depth: Some(2),
264            result: "ok",
265            error_type: None,
266            session_id: None,
267            seq: None,
268        };
269        let json = serde_json::to_string(&event).unwrap();
270        assert!(json.contains("analyze_directory"));
271        assert!(json.contains(r#""result":"ok""#));
272        assert!(json.contains(r#""output_chars":100"#));
273    }
274
275    #[test]
276    fn test_metric_event_serialization_error() {
277        let event = MetricEvent {
278            ts: 1_700_000_000_000,
279            tool: "analyze_directory",
280            duration_ms: 5,
281            output_chars: 0,
282            param_path_depth: 3,
283            max_depth: Some(3),
284            result: "error",
285            error_type: Some("invalid_params".to_string()),
286            session_id: None,
287            seq: None,
288        };
289        let json = serde_json::to_string(&event).unwrap();
290        assert!(json.contains(r#""result":"error""#));
291        assert!(json.contains(r#""error_type":"invalid_params""#));
292        assert!(json.contains(r#""output_chars":0"#));
293        assert!(json.contains(r#""max_depth":3"#));
294    }
295
296    #[test]
297    fn test_metric_event_new_fields_round_trip() {
298        let event = MetricEvent {
299            ts: 1_700_000_000_000,
300            tool: "analyze_file",
301            duration_ms: 100,
302            output_chars: 500,
303            param_path_depth: 2,
304            max_depth: Some(3),
305            result: "ok",
306            error_type: None,
307            session_id: Some("1742468880123-42".to_string()),
308            seq: Some(5),
309        };
310        let serialized = serde_json::to_string(&event).unwrap();
311        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}"#;
312        assert_eq!(serialized, json_str);
313        let parsed: MetricEvent = serde_json::from_str(json_str).unwrap();
314        assert_eq!(parsed.session_id, Some("1742468880123-42".to_string()));
315        assert_eq!(parsed.seq, Some(5));
316    }
317
318    #[test]
319    fn test_metric_event_backward_compat_parse() {
320        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}"#;
321        let parsed: MetricEvent = serde_json::from_str(old_jsonl).unwrap();
322        assert_eq!(parsed.tool, "analyze_directory");
323        assert_eq!(parsed.session_id, None);
324        assert_eq!(parsed.seq, None);
325    }
326
327    #[test]
328    fn test_session_id_format() {
329        let event = MetricEvent {
330            ts: 1_700_000_000_000,
331            tool: "analyze_symbol",
332            duration_ms: 20,
333            output_chars: 50,
334            param_path_depth: 1,
335            max_depth: None,
336            result: "ok",
337            error_type: None,
338            session_id: Some("1742468880123-0".to_string()),
339            seq: Some(0),
340        };
341        let sid = event.session_id.unwrap();
342        assert!(sid.contains('-'), "session_id should contain a dash");
343        let parts: Vec<&str> = sid.split('-').collect();
344        assert_eq!(parts.len(), 2, "session_id should have exactly 2 parts");
345        assert!(parts[0].len() == 13, "millis part should be 13 digits");
346    }
347}
code_analyze_mcp/metrics.rs

code_analyze_mcp/
metrics.rs
