Add new entrypoint option to --load-extensions. (#1789)

Thanks, @asg017

datasette/app.py

@@ -559,7 +559,13 @@ class Datasette:
         if self.sqlite_extensions:
             conn.enable_load_extension(True)
             for extension in self.sqlite_extensions:
-                conn.execute("SELECT load_extension(?)", [extension])
+                # "extension" is either a string path to the extension 
+                # or a 2-item tuple that specifies which entrypoint to load. 
+                if isinstance(extension, tuple):
+                    path, entrypoint = extension
+                    conn.execute("SELECT load_extension(?, ?)", [path, entrypoint])
+                else:
+                    conn.execute("SELECT load_extension(?)", [extension])
         if self.setting("cache_size_kb"):
             conn.execute(f"PRAGMA cache_size=-{self.setting('cache_size_kb')}")
         # pylint: disable=no-member

datasette/cli.py

@@ -21,6 +21,7 @@ from .app import (
     pm,
 )
 from .utils import (
+    LoadExtension,
     StartupError,
     check_connection,
     find_spatialite,
@@ -128,9 +129,10 @@ def sqlite_extensions(fn):
     return click.option(
         "sqlite_extensions",
         "--load-extension",
+        type=LoadExtension(),
         envvar="SQLITE_EXTENSIONS",
         multiple=True,
-        help="Path to a SQLite extension to load",
+        help="Path to a SQLite extension to load, and optional entrypoint",
     )(fn)
 
 

datasette/utils/__init__.py

@@ -833,6 +833,17 @@ class StaticMount(click.ParamType):
             self.fail(f"{value} is not a valid directory path", param, ctx)
         return path, dirpath
 
+# The --load-extension parameter can optionally include a specific entrypoint.
+# This is done by appending ":entrypoint_name" after supplying the path to the extension
+class LoadExtension(click.ParamType):
+    name = "path:entrypoint?"
+
+    def convert(self, value, param, ctx):
+        if ":" not in value:
+            return value
+        path, entrypoint = value.split(":", 1)
+        return path, entrypoint
+
 
 def format_bytes(bytes):
     current = float(bytes)