migrate snippets from gitlab

pickle_cache.py

@@ -0,0 +1,40 @@
+def pickle_cache(mode="auto"):
+    
+    def pc_decorator(func):
+
+        def pc_wrapper(*args, **kwargs):
+            cache_fp = Path(PROXY_DIR, f"{func.__name__}.pickle")
+            today = dt.date.today()
+            if cache_fp.exists():
+                statinfo = cache_fp.stat()
+                # (st_mode, st_ino, st_dev, st_nlink, st_uid, st_gid, st_size, st_atime, st_mtime, st_ctime) = statinfo
+                (_, _, _, _, _, _, _, _, st_mtime, _) = statinfo
+                mdate = dt.datetime.fromtimestamp(st_mtime).date()
+            else:
+                mdate = None
+            if mode == "auto":
+                if cache_fp.exists() and mdate == today:
+                    action = "cached"
+                else:
+                    action = "query"
+            else:
+                action = mode
+            if action == "cached" :
+                LOG.info(f"{func.__name__}: loading cached data...")
+                with cache_fp.open("rb") as fh:
+                    rc = pickle.load(fh)
+            elif action == "query":
+                LOG.info(f"{func.__name__}: database access...")
+                rc = func(*args, **kwargs)
+                if cache_fp.exists() and mdate != today and Path(PROXY_DIR, "Archive").exists():
+                    archive_fp = Path(PROXY_DIR, "Archive", f"{func.__name__}-{mdate:%Y%m%d}.pickle")
+                    shutil.copy(cache_fp, archive_fp)
+                with cache_fp.open("wb") as fh:
+                    pickle.dump(rc, fh)
+            else:
+                LOG.error(f"{func.__name__}: mode {action} unknown")
+            return rc
+
+        return pc_wrapper
+
+    return pc_decorator