add log rotation for .exo/exo.log (#1438)

## Motivation

.exo.log currently contains all past history. This just makes it hard to
read and is unnecessarily expensive even on disk.

## Why It Works

Just uses loguru's rotation.

## Test Plan

### Manual Testing
exo.log is new. 
<img width="1992" height="706" alt="image"
src="https://github.com/user-attachments/assets/9b293993-1141-43e7-b58e-0ddd2d4eda2e"
/>

app/EXO/EXO/ExoProcessController.swift

@@ -28,6 +28,10 @@ final class ExoProcessController: ObservableObject {
         }
     }
 
+    static let exoDirectoryURL: URL = {
+        URL(fileURLWithPath: NSHomeDirectory()).appendingPathComponent(".exo")
+    }()
+
     @Published private(set) var status: Status = .stopped
     @Published private(set) var lastError: String?
     @Published private(set) var launchCountdownSeconds: Int?
@@ -78,7 +82,11 @@ final class ExoProcessController: ObservableObject {
 
             let child = Process()
             child.executableURL = executableURL
-            child.currentDirectoryURL = runtimeURL
+            let exoHomeURL = Self.exoDirectoryURL
+            try? FileManager.default.createDirectory(
+                at: exoHomeURL, withIntermediateDirectories: true
+            )
+            child.currentDirectoryURL = exoHomeURL
             child.environment = makeEnvironment(for: runtimeURL)
 
             child.standardOutput = FileHandle.nullDevice

rust/networking/src/swarm.rs

@@ -106,7 +106,6 @@ mod behaviour {
     use crate::{alias, discovery};
     use libp2p::swarm::NetworkBehaviour;
     use libp2p::{gossipsub, identity};
-    use std::time::Duration;
 
     /// Behavior of the Swarm which composes all desired behaviors:
     /// Right now its just [`discovery::Behaviour`] and [`gossipsub::Behaviour`].
@@ -134,7 +133,6 @@ mod behaviour {
         gossipsub::Behaviour::new(
             MessageAuthenticity::Signed(keypair.clone()),
             ConfigBuilder::default()
-                .publish_queue_duration(Duration::from_secs(15))
                 .max_transmit_size(1024 * 1024)
                 .validation_mode(ValidationMode::Strict)
                 .build()

src/exo/routing/router.py

@@ -207,10 +207,10 @@ class Router:
                 try:
                     logger.trace(f"Sending message on {topic} with payload {data}")
                     await self._net.gossipsub_publish(topic, data)
-                # As a hack, this also catches AllQueuesFull
-                # Need to fix that ASAP.
-                except (NoPeersSubscribedToTopicError, AllQueuesFullError):
+                except NoPeersSubscribedToTopicError:
                     pass
+                except AllQueuesFullError:
+                    logger.warning(f"All peer queues full, dropping message on {topic}")
 
 
 def get_node_id_keypair(

src/exo/shared/logging.py

@@ -1,11 +1,30 @@
 import logging
 import sys
+from collections.abc import Iterator
 from pathlib import Path
 
+import zstandard
 from hypercorn import Config
 from hypercorn.logging import Logger as HypercornLogger
 from loguru import logger
 
+_MAX_LOG_ARCHIVES = 5
+
+
+def _zstd_compress(filepath: str) -> None:
+    source = Path(filepath)
+    dest = source.with_suffix(source.suffix + ".zst")
+    cctx = zstandard.ZstdCompressor()
+    with open(source, "rb") as f_in, open(dest, "wb") as f_out:
+        cctx.copy_stream(f_in, f_out)
+    source.unlink()
+
+
+def _once_then_never() -> Iterator[bool]:
+    yield True
+    while True:
+        yield False
+
 
 class InterceptLogger(HypercornLogger):
     def __init__(self, config: Config):
@@ -53,13 +72,16 @@ def logger_setup(log_file: Path | None, verbosity: int = 0):
             enqueue=True,
         )
     if log_file:
+        rotate_once = _once_then_never()
         logger.add(
             log_file,
             format="[ {time:YYYY-MM-DD HH:mm:ss.SSS} | {level: <8} | {name}:{function}:{line} ] {message}",
             level="INFO",
             colorize=False,
             enqueue=True,
-            rotation="1 week",
+            rotation=lambda _, __: next(rotate_once),
+            retention=_MAX_LOG_ARCHIVES,
+            compression=_zstd_compress,
         )