initial

pyfdb/pyfdb.py

@@ -40,8 +40,8 @@ class PatchedLib:
     and patches the accessors with automatic python-C error handling.
     """
 
-    def __init__(self):
-        self.path = findlibs.find("fdb5")
+    def __init__(self, lib_path=None):
+        self.path = lib_path or findlibs.find("fdb5")
 
         if self.path is None:
             raise RuntimeError("FDB5 library not found")
@@ -102,9 +102,8 @@ def __repr__(self):
         return f"<pyfdb.pyfdb.PatchedLib FDB5 version {self.version} from {self.path}>"
 
 
-# Bootstrap the library
-
-lib = PatchedLib()
+# Lazy load the library to avoid loading it when the module is imported
+lib = None
 
 
 class Key:
@@ -296,7 +295,14 @@ class FDB:
 
     __fdb = None
 
-    def __init__(self, config=None, user_config=None):
+    def __init__(self, config=None, user_config=None, lib_path=None):
+        global lib
+        print("lib", lib)
+        if lib is None:
+            print("loading library")
+            lib = PatchedLib(lib_path)
+            print("lib", lib)
+
         fdb = ffi.new("fdb_handle_t**")
 
         if config is not None or user_config is not None:

tests/test_lib.py

@@ -0,0 +1,40 @@
+from pathlib import Path
+from tempfile import TemporaryDirectory
+
+import findlibs
+
+import pyfdb
+
+
+def test_lib_path():
+    # pyfdb uses findlibs internally to locate the library
+    # So this looks a bit circular but it's just to check that we can pass a path explicitly
+    # The `libpath` argument allows the user to hard code the path to the library.
+    # This should not be necessary in normal usage but it's a useful backup.
+    lib_path = findlibs.find("fdb5")
+
+    with TemporaryDirectory() as tmp_root:
+        tests_dir = Path(__file__).parent
+
+        config = dict(
+            type="local",
+            engine="toc",
+            schema=str(tests_dir / "default_fdb_schema"),
+            spaces=[
+                dict(
+                    handler="Default",
+                    roots=[
+                        {"path": tmp_root, "write": True},
+                    ],
+                )
+            ],
+        )
+
+    fdb = pyfdb.FDB(config=config)
+    data = open(tests_dir / "x138-300.grib", "rb").read()
+    fdb.archive(data)
+    fdb.flush()
+    list_output = list(fdb.list(keys=True))
+    assert len(list_output) == 1
+    print("external lib", pyfdb.lib)
+    assert pyfdb.lib.path == lib_path