sloop/
logging.rs

1use std::fs::{self, File, OpenOptions};
2use std::io::{self, Write};
3use std::path::Path;
4use std::sync::{Arc, Mutex};
5
6use serde::Serialize;
7use serde_json::Value;
8use time::OffsetDateTime;
9use time::format_description::well_known::Rfc3339;
10
11#[derive(Clone)]
12pub struct OperationalLog {
13    file: Arc<Mutex<File>>,
14}
15
16impl OperationalLog {
17    pub fn open(path: &Path) -> io::Result<Self> {
18        if let Some(parent) = path.parent() {
19            fs::create_dir_all(parent)?;
20        }
21        let file = OpenOptions::new().create(true).append(true).open(path)?;
22        Ok(Self {
23            file: Arc::new(Mutex::new(file)),
24        })
25    }
26
27    pub fn emit(&self, level: LogLevel, target: &'static str, event: &'static str) {
28        self.emit_fields(level, target, event, None);
29    }
30
31    /// Writes caller-selected operational context. Callers must keep fields
32    /// to identifiers, classifications, and errors; prompts and credentials
33    /// never belong in the operational log.
34    pub fn emit_with_fields(
35        &self,
36        level: LogLevel,
37        target: &'static str,
38        event: &'static str,
39        fields: Value,
40    ) {
41        self.emit_fields(level, target, event, Some(fields));
42    }
43
44    fn emit_fields(
45        &self,
46        level: LogLevel,
47        target: &'static str,
48        event: &'static str,
49        fields: Option<Value>,
50    ) {
51        let timestamp = OffsetDateTime::now_utc()
52            .format(&Rfc3339)
53            .unwrap_or_else(|_| "1970-01-01T00:00:00Z".into());
54        let record = OperationalRecord {
55            timestamp,
56            level,
57            target,
58            event,
59            fields,
60        };
61        let Ok(mut file) = self.file.lock() else {
62            return;
63        };
64        if serde_json::to_writer(&mut *file, &record).is_ok() {
65            let _ = file.write_all(b"\n");
66            let _ = file.flush();
67        }
68    }
69}
70
71#[derive(Debug, Clone, Copy, Serialize)]
72#[serde(rename_all = "snake_case")]
73pub enum LogLevel {
74    Error,
75    Info,
76}
77
78#[derive(Debug, Serialize)]
79struct OperationalRecord {
80    timestamp: String,
81    level: LogLevel,
82    target: &'static str,
83    event: &'static str,
84    #[serde(skip_serializing_if = "Option::is_none")]
85    fields: Option<Value>,
86}
87
88#[cfg(test)]
89mod tests {
90    use std::fs;
91
92    use serde_json::Value;
93    use tempfile::tempdir;
94
95    use super::{LogLevel, OperationalLog};
96
97    #[test]
98    fn writes_one_structured_record_per_line() {
99        let root = tempdir().unwrap();
100        let path = root.path().join("logs/daemon.ndjson");
101        let log = OperationalLog::open(&path).unwrap();
102
103        log.emit(LogLevel::Info, "sloop::daemon", "daemon_started");
104
105        let contents = fs::read_to_string(path).unwrap();
106        let record: Value = serde_json::from_str(contents.trim_end()).unwrap();
107        assert_eq!(record["level"], "info");
108        assert_eq!(record["target"], "sloop::daemon");
109        assert_eq!(record["event"], "daemon_started");
110        assert!(record["timestamp"].as_str().unwrap().ends_with('Z'));
111    }
112
113    #[test]
114    fn writes_safe_context_as_structured_fields() {
115        let root = tempdir().unwrap();
116        let path = root.path().join("logs/daemon.ndjson");
117        let log = OperationalLog::open(&path).unwrap();
118
119        log.emit_with_fields(
120            LogLevel::Error,
121            "sloop::dispatcher",
122            "run_exit_persist_failed",
123            serde_json::json!({"run_id": "R7", "error": "database is busy"}),
124        );
125
126        let contents = fs::read_to_string(path).unwrap();
127        let record: Value = serde_json::from_str(contents.trim_end()).unwrap();
128        assert_eq!(record["fields"]["run_id"], "R7");
129        assert_eq!(record["fields"]["error"], "database is busy");
130    }
131}
sloop/logging.rs

sloop/
logging.rs
