From f2fd7d20bf3d1ca7ea486e3e40f27576d44f39d0 Mon Sep 17 00:00:00 2001
From: Simon Willison <swillison@gmail.com>
Date: Sat, 15 Feb 2020 09:28:48 -0800
Subject: [PATCH] Run scan_dirs in a thread every 10 seconds

---
 datasette/app.py | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/datasette/app.py b/datasette/app.py
index c0071d2a..1b8be011 100644
--- a/datasette/app.py
+++ b/datasette/app.py
@@ -7,6 +7,7 @@ import os
 import re
 import sys
 import threading
+import time
 import traceback
 import urllib.parse
 from concurrent import futures
@@ -186,8 +187,11 @@ class Datasette:
             if db.name in self.databases:
                 raise Exception("Multiple files with same stem: {}".format(db.name))
             self.add_database(db.name, db)
-        self.scan_dirs_executor = futures.ThreadPoolExecutor(max_workers=1)
-        self.scan_dirs_executor.submit(self.scan_dirs)
+        if dirs:
+            self.scan_dirs_thread = threading.Thread(
+                target=self.scan_dirs, name="scan-dirs", daemon=True
+            )
+            self.scan_dirs_thread.start()
         self.cache_headers = cache_headers
         self.cors = cors
         self._metadata = metadata or {}
@@ -225,18 +229,24 @@ class Datasette:
 
     def scan_dirs(self):
         # Recurse through self.dirs looking for new SQLite DBs
-        for dir in self.dirs:
-            print(dir)
-            for filepath in Path(dir).glob("**/*.db"):
-                print(filepath)
-                if is_valid_sqlite(filepath):
-                    self.add_database(
-                        str(filepath)
-                        .replace("../", "")
-                        .replace("/", "_")
-                        .replace(".db", ""),
-                        Database(self, filepath, is_mutable=True),
-                    )
+        while True:
+            current_filepaths = {
+                d.path for d in list(self.databases.values()) if d.path is not None
+            }
+            for dir in self.dirs:
+                for filepath in Path(dir).glob("**/*.db"):
+                    if str(filepath) in current_filepaths:
+                        continue
+                    print(filepath)
+                    if is_valid_sqlite(filepath):
+                        self.add_database(
+                            str(filepath)
+                            .replace("../", "")
+                            .replace("/", "_")
+                            .replace(".db", ""),
+                            Database(self, str(filepath), is_mutable=True),
+                        )
+            time.sleep(10)
 
     def config(self, key):
         return self._config.get(key, None)