feat(admin): observability — job history, live now-analyzing, durations & metrics (0.84.0) (#6)

backend/src/config.rs

@@ -321,6 +321,10 @@ pub struct CrawlerConfig {
     pub idle_timeout: Duration,
     pub chapter_workers: usize,
     pub retention_days: u32,
+    /// Days to keep `crawl_metrics` timing rows before reaping. `0`
+    /// disables the reaper. Defaults to 90 (volume is low — one row per
+    /// manga/chapter/pass, not per image). `CRAWL_METRICS_RETENTION_DAYS`.
+    pub metrics_retention_days: u32,
     pub start_url: Option<String>,
     pub rate_ms: u64,
     pub cdn_host: Option<String>,
@@ -379,6 +383,7 @@ impl Default for CrawlerConfig {
             idle_timeout: Duration::from_secs(600),
             chapter_workers: 1,
             retention_days: 7,
+            metrics_retention_days: 90,
             start_url: None,
             rate_ms: 1000,
             cdn_host: None,
@@ -500,6 +505,7 @@ impl CrawlerConfig {
             idle_timeout: Duration::from_secs(env_u64("CRAWLER_IDLE_TIMEOUT_S", 600)),
             chapter_workers: env_u64("CRAWLER_CHAPTER_WORKERS", 1).max(1) as usize,
             retention_days: env_u64("CRAWLER_JOB_RETENTION_DAYS", 7) as u32,
+            metrics_retention_days: env_u64("CRAWL_METRICS_RETENTION_DAYS", 90) as u32,
             start_url,
             rate_ms: env_u64("CRAWLER_RATE_MS", 1000),
             cdn_host,
@@ -583,7 +589,7 @@ fn build_download_allowlist(
     allow
 }
 
-fn env_u64(name: &str, default: u64) -> u64 {
+pub(crate) fn env_u64(name: &str, default: u64) -> u64 {
     std::env::var(name)
         .ok()
         .and_then(|s| s.parse().ok())