New introspection endpoint: /-/databases - closes #470

Refs #419 and #465

datasette/app.py

@@ -549,6 +549,19 @@ def register_custom_units(self):
         for unit in self.metadata("custom_units") or []:
             ureg.define(unit)
 
+    def connected_databases(self):
+        return [
+            {
+                "name": d.name,
+                "path": d.path,
+                "size": d.size,
+                "is_mutable": d.is_mutable,
+                "is_memory": d.is_memory,
+                "hash": d.hash,
+            }
+            for d in self.databases.values()
+        ]
+
     def versions(self):
         conn = sqlite3.connect(":memory:")
         self.prepare_connection(conn)
@@ -810,6 +823,10 @@ async def handle_request(self, request, write_callback, stream_callback):
             JsonDataView.as_view(self, "config.json", lambda: self._config),
             r"/-/config<as_format:(\.json)?$>",
         )
+        app.add_route(
+            JsonDataView.as_view(self, "databases.json", self.connected_databases),
+            r"/-/databases<as_format:(\.json)?$>",
+        )
         app.add_route(
             DatabaseDownload.as_view(self), r"/<db_name:[^/]+?><as_db:(\.db)$>"
         )

docs/introspection.rst

@@ -89,3 +89,19 @@ Shows the :ref:`config` options for this instance of Datasette. `Config example
         "max_returned_rows": 1000,
         "sql_time_limit_ms": 1000
     }
+
+/-/databases
+------------
+
+Shows currently attached databases. `Databases example <https://latest.datasette.io/-/config>`_::
+
+    [
+        {
+            "hash": null,
+            "is_memory": false,
+            "is_mutable": true,
+            "name": "fixtures",
+            "path": "fixtures.db",
+            "size": 225280
+        }
+    ]

tests/fixtures.py

@@ -100,6 +100,13 @@ def app_client_two_attached_databases():
     )
 
 
+@pytest.fixture(scope="session")
+def app_client_two_attached_databases_one_immutable():
+    yield from make_app_client(
+        is_immutable=True, extra_databases={"extra_database.db": EXTRA_DATABASE_SQL}
+    )
+
+
 @pytest.fixture(scope="session")
 def app_client_with_memory():
     yield from make_app_client(memory=True)

tests/test_api.py

@@ -6,6 +6,7 @@
     app_client_shorter_time_limit,
     app_client_larger_cache_size,
     app_client_returned_rows_matches_page_size,
+    app_client_two_attached_databases_one_immutable,
     app_client_with_cors,
     app_client_with_dot,
     generate_compound_rows,
@@ -1058,6 +1059,22 @@ def test_unit_filters(app_client):
     assert data["rows"][0][0] == 2
 
 
+def test_databases_json(app_client_two_attached_databases_one_immutable):
+    response = app_client_two_attached_databases_one_immutable.get("/-/databases.json")
+    databases = response.json
+    assert 2 == len(databases)
+    extra_database, fixtures_database = databases
+    assert "extra_database" == extra_database["name"]
+    assert None == extra_database["hash"]
+    assert True == extra_database["is_mutable"]
+    assert False == extra_database["is_memory"]
+
+    assert "fixtures" == fixtures_database["name"]
+    assert fixtures_database["hash"] is not None
+    assert False == fixtures_database["is_mutable"]
+    assert False == fixtures_database["is_memory"]
+
+
 def test_metadata_json(app_client):
     response = app_client.get("/-/metadata.json")
     assert METADATA == response.json