fix: move TESTCONTAINERS_HOST_OVERRIDE to config.py (#603)

fix #602

Author: alexanderankin

core/testcontainers/core/config.py

@@ -14,6 +14,7 @@
 RYUK_DISABLED: bool = environ.get("TESTCONTAINERS_RYUK_DISABLED", "false") == "true"
 RYUK_DOCKER_SOCKET: str = environ.get("TESTCONTAINERS_DOCKER_SOCKET_OVERRIDE", "/var/run/docker.sock")
 RYUK_RECONNECTION_TIMEOUT: str = environ.get("RYUK_RECONNECTION_TIMEOUT", "10s")
+TC_HOST_OVERRIDE: Optional[str] = environ.get("TC_HOST", environ.get("TESTCONTAINERS_HOST_OVERRIDE"))
 
 TC_FILE = ".testcontainers.properties"
 TC_GLOBAL = Path.home() / TC_FILE
@@ -52,6 +53,11 @@ class TestcontainersConfiguration:
     ryuk_reconnection_timeout: str = RYUK_RECONNECTION_TIMEOUT
     tc_properties: dict[str, str] = field(default_factory=read_tc_properties)
     _docker_auth_config: Optional[str] = field(default_factory=lambda: environ.get("DOCKER_AUTH_CONFIG"))
+    tc_host_override: Optional[str] = TC_HOST_OVERRIDE
+    """
+    https://github.com/testcontainers/testcontainers-go/blob/dd76d1e39c654433a3d80429690d07abcec04424/docker.go#L644
+    if os env TC_HOST is set, use it
+    """
 
     @property
     def docker_auth_config(self):

core/testcontainers/core/docker_client.py

@@ -187,18 +187,14 @@ def host(self) -> str:
         """
         Get the hostname or ip address of the docker host.
         """
-        # https://github.com/testcontainers/testcontainers-go/blob/dd76d1e39c654433a3d80429690d07abcec04424/docker.go#L644
-        # if os env TC_HOST is set, use it
-        host = os.environ.get("TC_HOST")
-        if not host:
-            host = os.environ.get("TESTCONTAINERS_HOST_OVERRIDE")
+        host = c.tc_host_override
         if host:
             return host
         try:
             url = urllib.parse.urlparse(self.client.api.base_url)
 
         except ValueError:
-            return None
+            return "localhost"
         if "http" in url.scheme or "tcp" in url.scheme:
             return url.hostname
         if inside_container() and ("unix" in url.scheme or "npipe" in url.scheme):