feat: add connectors for using environment variables or fixed example…

…s server

examples/local_cache.py

@@ -2,13 +2,8 @@
 
 import letsql as ls
 
-pg = ls.postgres.connect(
-    # FIXME: use dyndns to point examples.letsql.com to the gcp sql host
-    host="34.135.241.141",
-    user="letsql",
-    password="letsql",
-    database="letsql",
-)
+
+pg = ls.postgres.connect_examples()
 con = ls.connect()  # empty connection
 storage = ls.common.caching.ParquetCacheStorage(
     source=con,

examples/multi_engine.py

@@ -1,18 +1,9 @@
-import ibis
-
 import letsql as ls
 
 
 con = ls.connect()  # empty connection
-
-pg = ls.postgres.connect(
-    # FIXME: use dyndns to point examples.letsql.com to the gcp sql host
-    host="34.135.241.141",
-    user="letsql",
-    password="letsql",
-    database="letsql",
-)
-db = ibis.duckdb.connect()
+pg = ls.postgres.connect_examples()
+db = ls.duckdb.connect()
 
 
 batting = pg.table("batting").pipe(con.register, table_name="batting")

python/letsql/backends/postgres/__init__.py

@@ -19,6 +19,23 @@
 
 
 class Backend(IbisPostgresBackend):
+    _top_level_methods = ("connect_examples", "connect_env")
+
+    @classmethod
+    def connect_env(cls, **kwargs):
+        from letsql.common.utils.postgres_utils import make_connection
+
+        return make_connection(**kwargs)
+
+    @classmethod
+    def connect_examples(cls):
+        return cls().connect(
+            host="examples.letsql.com",
+            user="letsql",
+            password="letsql",
+            database="letsql",
+        )
+
     @staticmethod
     def _register_and_transform_cache_tables(expr):
         """This function will sequentially execute any cache node that is not already cached"""

python/letsql/backends/snowflake/__init__.py

@@ -10,6 +10,14 @@
 
 
 class Backend(IbisSnowflakeBackend):
+    _top_level_methods = ("connect_env",)
+
+    @classmethod
+    def connect_env(cls, database="SNOWFLAKE_SAMPLE_DATA", schema="TPCH_SF1", **kwargs):
+        from letsql.common.utils.snowflake_utils import make_connection
+
+        return make_connection(database=database, schema=schema, **kwargs)
+
     @staticmethod
     def _register_and_transform_cache_tables(expr):
         """This function will sequentially execute any cache node that is not already cached"""