From d81d3675f836ad69075bbce7a3534cc62a233893 Mon Sep 17 00:00:00 2001
From: Wind-Explorer <windexplorer@outlook.com>
Date: Tue, 11 Aug 2026 02:41:18 +0800
Subject: [PATCH] fix old log loading

---
 frontend/src/App.svelte |   5 +-
 src/http/mod.rs         |  10 ++-
 src/logs/index.rs       | 143 +++++++++++++++++++++++++++++++++++++---
 3 files changed, 145 insertions(+), 13 deletions(-)

diff --git a/frontend/src/App.svelte b/frontend/src/App.svelte
index 932f149..5f5d61a 100644
--- a/frontend/src/App.svelte
+++ b/frontend/src/App.svelte
@@ -1,9 +1,10 @@
 <script lang="ts">
 import {onMount} from 'svelte';import {backoff,mergeLines,type LogLine,type Page} from './lib';
 let lines:LogLine[]=[];let before:string|null=null;let hasMore=true;let state:'Connecting'|'Live'|'Reconnecting'|'Disconnected'|'Access denied'='Connecting';let viewport:HTMLDivElement;let atBottom=true;let unseen=0;let loading=false;let socket:WebSocket|null=null;let stopped=false;let clientIp:string|null=null;let showIp=false;
-async function fetchPage(cursor:string|null,limit=1000){const endpoint=cursor?`/api/logs/history?before=${encodeURIComponent(cursor)}&limit=${limit}`:`/api/logs/recent?limit=${limit}`;const response=await fetch(endpoint);if(response.status===403){const denial=await response.json().catch(()=>null) as {client_ip?:string}|null;clientIp=denial?.client_ip??null;state='Access denied';throw new Error('denied')}if(!response.ok)throw new Error('history');return response.json() as Promise<Page>}
+class HistoryError extends Error{status:number;code:string;constructor(status:number,code:string){super(code);this.status=status;this.code=code}}
+async function fetchPage(cursor:string|null,limit=1000){const endpoint=cursor?`/api/logs/history?before=${encodeURIComponent(cursor)}&limit=${limit}`:`/api/logs/recent?limit=${limit}`;const response=await fetch(endpoint);if(response.status===403){const denial=await response.json().catch(()=>null) as {client_ip?:string}|null;clientIp=denial?.client_ip??null;state='Access denied';throw new HistoryError(403,'denied')}if(!response.ok){const failure=await response.json().catch(()=>null) as {error?:string}|null;throw new HistoryError(response.status,failure?.error??'history')}return response.json() as Promise<Page>}
 async function initial(){const page=await fetchPage(null);lines=mergeLines([],page.lines);before=page.next_before;hasMore=page.has_more;requestAnimationFrame(scrollLive);}
-async function older(){if(loading||!hasMore||!before)return;loading=true;const oldHeight=viewport.scrollHeight;try{const page=await fetchPage(before);const ids=new Set(lines.map(x=>x.id));lines=[...page.lines.filter(x=>!ids.has(x.id)),...lines];before=page.next_before;hasMore=page.has_more;requestAnimationFrame(()=>viewport.scrollTop+=viewport.scrollHeight-oldHeight);}finally{loading=false}}
+async function older(){if(loading||!hasMore||!before)return;loading=true;const oldHeight=viewport.scrollHeight;try{const page=await fetchPage(before);const ids=new Set(lines.map(x=>x.id));lines=[...page.lines.filter(x=>!ids.has(x.id)),...lines];before=page.next_before;hasMore=page.has_more;requestAnimationFrame(()=>viewport.scrollTop+=viewport.scrollHeight-oldHeight);}catch(error){if(error instanceof HistoryError&&error.status===409&&error.code==='stale_cursor'){try{const page=await fetchPage(null);lines=mergeLines(lines,page.lines);before=page.next_before;hasMore=page.has_more;requestAnimationFrame(()=>older());}catch(recoveryError){console.error('Failed to refresh changed log history',recoveryError)}}else{console.error('Failed to load older logs',error)}}finally{loading=false}}
 function connect(attempt=0){if(stopped||state==='Access denied')return;state=attempt?'Reconnecting':'Connecting';const scheme=location.protocol==='https:'?'wss':'ws';socket=new WebSocket(`${scheme}://${location.host}/api/live`);socket.onopen=async()=>{state='Live';try{const gap=await fetchPage(null,1000);lines=mergeLines(lines,gap.lines);if(atBottom)requestAnimationFrame(scrollLive)}catch{}};socket.onmessage=(event)=>{const message=JSON.parse(event.data);if(message.type==='log_lines'){lines=mergeLines(lines,message.lines);if(atBottom)requestAnimationFrame(scrollLive);else unseen+=message.lines.length}if(message.type==='resync_required')socket?.close()};socket.onclose=()=>{if(stopped||state==='Access denied')return;state='Reconnecting';setTimeout(()=>connect(attempt+1),backoff(attempt))};socket.onerror=()=>socket?.close()}
 function scrollLive(){viewport?.scrollTo({top:viewport.scrollHeight});unseen=0}
 function scroll(){atBottom=viewport.scrollHeight-viewport.scrollTop-viewport.clientHeight<40;if(atBottom)unseen=0;if(viewport.scrollTop<200)older()}
diff --git a/src/http/mod.rs b/src/http/mod.rs
index 235ee9a..a54b6c5 100644
--- a/src/http/mod.rs
+++ b/src/http/mod.rs
@@ -82,8 +82,14 @@ async fn logs_response(
     match state.history.page(before, limit).await {
         Ok(page) => Json(page).into_response(),
         Err(code) if code == "invalid_cursor" => error(StatusCode::BAD_REQUEST, "invalid_cursor"),
-        Err(code) if code == "stale_cursor" => error(StatusCode::CONFLICT, "stale_cursor"),
-        Err(_) => error(StatusCode::UNPROCESSABLE_ENTITY, "history_unavailable"),
+        Err(code) if code == "stale_cursor" => {
+            tracing::debug!(event = "history_page_failed", reason = "stale_cursor");
+            error(StatusCode::CONFLICT, "stale_cursor")
+        }
+        Err(code) => {
+            tracing::warn!(event = "history_page_failed", reason = %code);
+            error(StatusCode::UNPROCESSABLE_ENTITY, "history_unavailable")
+        }
     }
 }
 
diff --git a/src/logs/index.rs b/src/logs/index.rs
index 70af7a7..622ff3c 100644
--- a/src/logs/index.rs
+++ b/src/logs/index.rs
@@ -35,7 +35,10 @@ impl HistoryIndex {
         for entry in fs::read_dir(dir)? {
             let entry = entry?;
             let path = entry.path();
-            if !entry.file_type()?.is_file() || archive::detect(&path).is_none() {
+            if !entry.file_type()?.is_file()
+                || is_debug_log(&path)
+                || archive::detect(&path).is_none()
+            {
                 continue;
             }
             let meta = entry.metadata()?;
@@ -75,6 +78,38 @@ impl HistoryIndex {
             generation,
         })
     }
+
+    // A cursor remains valid while latest.log only grows: existing source and
+    // line positions do not move. Archive changes, rotation, and truncation do
+    // change pagination and must invalidate outstanding cursors.
+    fn is_append_compatible_with(&self, previous: &Self) -> bool {
+        self.sources.len() == previous.sources.len()
+            && self
+                .sources
+                .iter()
+                .zip(&previous.sources)
+                .all(|(new, old)| {
+                    new.label == old.label
+                        && new.path == old.path
+                        && new.device == old.device
+                        && new.inode == old.inode
+                        && if new.label == "latest.log" {
+                            new.compressed_size >= old.compressed_size
+                        } else {
+                            new.modified_ms == old.modified_ms
+                                && new.compressed_size == old.compressed_size
+                        }
+                })
+    }
+}
+fn is_debug_log(path: &Path) -> bool {
+    let name = path
+        .file_name()
+        .and_then(|name| name.to_str())
+        .unwrap_or_default()
+        .to_ascii_lowercase();
+    name == "debug.log"
+        || (name.starts_with("debug-") && (name.ends_with(".log") || name.ends_with(".log.gz")))
 }
 fn filename_key(name: &str) -> String {
     name.chars().filter(|c| c.is_ascii_digit()).collect()
@@ -105,7 +140,12 @@ impl ArchiveCache {
         }
     }
     fn get(&mut self, p: &Path) -> Option<Arc<Vec<String>>> {
-        self.items.get(p).cloned()
+        let value = self.items.get(p).cloned()?;
+        if let Some(position) = self.order.iter().position(|item| item == p) {
+            self.order.remove(position);
+        }
+        self.order.push_back(p.to_path_buf());
+        Some(value)
     }
     fn put(&mut self, p: PathBuf, v: Arc<Vec<String>>) {
         if self.max_files == 0 || self.max_bytes == 0 {
@@ -148,7 +188,12 @@ impl HistoryStore {
         }
     }
     pub async fn refresh(&self, dir: &Path) -> std::io::Result<()> {
-        *self.index.write().await = HistoryIndex::scan(dir)?;
+        let mut next = HistoryIndex::scan(dir)?;
+        let mut index = self.index.write().await;
+        if next.is_append_compatible_with(&index) {
+            next.generation = index.generation;
+        }
+        *index = next;
         Ok(())
     }
     pub async fn page(&self, before: Option<&str>, limit: usize) -> Result<HistoryPage, String> {
@@ -207,14 +252,22 @@ impl HistoryStore {
         })
     }
     fn load(&self, source: &Source) -> Result<Arc<Vec<String>>, archive::ArchiveError> {
-        if let Some(v) = self.cache.lock().unwrap().get(&source.path) {
-            return Ok(v);
+        let cacheable = matches!(
+            archive::detect(&source.path),
+            Some(archive::ArchiveKind::Gzip | archive::ArchiveKind::TarGzip)
+        );
+        if cacheable {
+            if let Some(v) = self.cache.lock().unwrap().get(&source.path) {
+                return Ok(v);
+            }
         }
         let v = Arc::new(archive::read_lines(&source.path, self.max_archive_bytes)?);
-        self.cache
-            .lock()
-            .unwrap()
-            .put(source.path.clone(), v.clone());
+        if cacheable {
+            self.cache
+                .lock()
+                .unwrap()
+                .put(source.path.clone(), v.clone());
+        }
         Ok(v)
     }
 }
@@ -236,6 +289,14 @@ fn make_line(source: &Source, index: usize, text: &str, redact: bool) -> LogLine
 #[cfg(test)]
 mod tests {
     use super::*;
+    use flate2::{write::GzEncoder, Compression};
+    use std::io::Write;
+
+    fn write_gzip(path: &Path, contents: &[u8]) {
+        let mut gzip = GzEncoder::new(fs::File::create(path).unwrap(), Compression::default());
+        gzip.write_all(contents).unwrap();
+        gzip.finish().unwrap();
+    }
     #[test]
     fn deterministic_filename_order() {
         let d = tempfile::tempdir().unwrap();
@@ -252,6 +313,23 @@ mod tests {
         let i = HistoryIndex::scan(d.path()).unwrap();
         assert_eq!(i.sources.last().unwrap().label, "latest.log");
     }
+    #[test]
+    fn excludes_minecraft_debug_logs() {
+        let d = tempfile::tempdir().unwrap();
+        fs::write(d.path().join("latest.log"), "normal\n").unwrap();
+        fs::write(d.path().join("debug.log"), "debug\n").unwrap();
+        write_gzip(&d.path().join("debug-1.log.gz"), b"rotated debug\n");
+
+        let index = HistoryIndex::scan(d.path()).unwrap();
+        assert_eq!(
+            index
+                .sources
+                .iter()
+                .map(|source| source.label.as_str())
+                .collect::<Vec<_>>(),
+            vec!["latest.log"]
+        );
+    }
     #[tokio::test]
     async fn paginates_without_exposing_paths() {
         let d = tempfile::tempdir().unwrap();
@@ -278,4 +356,51 @@ mod tests {
             vec!["old", "new"]
         );
     }
+
+    #[tokio::test]
+    async fn cursor_survives_latest_log_append_but_not_truncation() {
+        let d = tempfile::tempdir().unwrap();
+        let latest = d.path().join("latest.log");
+        fs::write(&latest, "one\ntwo\n").unwrap();
+        let store = HistoryStore::new(HistoryIndex::scan(d.path()).unwrap(), 1024, 2, 1024, false);
+        let cursor = store.page(None, 1).await.unwrap().next_before.unwrap();
+
+        fs::OpenOptions::new()
+            .append(true)
+            .open(&latest)
+            .unwrap()
+            .write_all(b"three\n")
+            .unwrap();
+        store.refresh(d.path()).await.unwrap();
+        assert!(store.page(Some(&cursor), 1).await.is_ok());
+
+        fs::write(&latest, "replacement\n").unwrap();
+        store.refresh(d.path()).await.unwrap();
+        assert_eq!(
+            store.page(Some(&cursor), 1).await.unwrap_err(),
+            "stale_cursor"
+        );
+    }
+
+    #[test]
+    fn evicted_archive_is_reloaded_on_demand() {
+        let d = tempfile::tempdir().unwrap();
+        let first_path = d.path().join("1.log.gz");
+        let second_path = d.path().join("2.log.gz");
+        write_gzip(&first_path, b"old\n");
+        write_gzip(&second_path, b"second\n");
+        let index = HistoryIndex::scan(d.path()).unwrap();
+        let first = index.sources.iter().find(|s| s.path == first_path).unwrap();
+        let second = index
+            .sources
+            .iter()
+            .find(|s| s.path == second_path)
+            .unwrap();
+        let store = HistoryStore::new(index.clone(), 1024, 1, 1024, false);
+
+        assert_eq!(store.load(first).unwrap()[0], "old");
+        assert_eq!(store.load(second).unwrap()[0], "second"); // evicts first
+        write_gzip(&first_path, b"reloaded\n");
+        assert_eq!(store.load(first).unwrap()[0], "reloaded");
+    }
 }