util/proxy: allow overriding LG_PROXY from the environment config

doc/man/device-config.rst

@@ -32,6 +32,8 @@ previous driver.
 For a list of available resources and drivers refer to
 https://labgrid.readthedocs.io/en/latest/configuration.html.
 
+.. _labgrid-device-config-options:
+
 OPTIONS
 -------
 The ``options:`` top key configures various options such as the coordinator_address.
@@ -42,6 +44,14 @@ OPTIONS KEYS
 ``coordinator_address``
   takes as parameter the coordinator ``HOST[:PORT]`` to connect to.
   Defaults to ``127.0.0.1:20408``.
+  Overrides the ``LG_COORDINATOR`` environment variable.
+
+``proxy``
+  takes as parameter the SSH proxy host used to tunnel connections to the
+  coordinator and to network resources.
+  Overrides the ``LG_PROXY`` environment variable.
+  Set it to an empty value (e.g. ``proxy:``) to force a direct connection
+  without a proxy, even when ``LG_PROXY`` is set.
 
 .. _labgrid-device-config-images:
 

doc/overview.rst

@@ -397,6 +397,13 @@ respective proxies. This means that with :code:`LG_PROXY` and
 :code:`LG_COORDINATOR` labgrid can be used fully remotely with only a SSH
 connection as a requirement.
 
+Instead of the environment variables, the :code:`proxy` and
+:code:`coordinator_address` options can be set in the environment config (see
+:ref:`labgrid-device-config-options`). The config options take precedence over
+the corresponding environment variables. Setting the :code:`proxy` option to an
+empty value forces a direct connection without a proxy, even when
+:code:`LG_PROXY` is set.
+
 .. note::
   Labgrid prefers to connect to an exporter-defined proxy over using the
   LG_PROXY variable. This means that a correct entry for the exporter needs to

doc/usage.rst

@@ -479,6 +479,10 @@ Specifies a SSH proxy host to be used for port forwards to access the
 coordinator. Network resources made available by the exporter will prefer their
 own proxy, and only fallback to LG_PROXY.
 
+This can be overridden by the ``proxy`` option in the environment config (see
+:ref:`labgrid-device-config-options`). Setting that option to an empty value
+forces a direct connection without a proxy, even when ``LG_PROXY`` is set.
+
 See also :ref:`overview-proxy-mechanism`.
 
 

labgrid/pytestplugin/hooks.py

@@ -6,6 +6,7 @@
 from .. import Environment
 from ..consoleloggingreporter import ConsoleLoggingReporter
 from ..util.helper import processwrapper
+from ..util.proxy import proxymanager
 from ..logging import StepFormatter, StepLogger
 from ..exceptions import NoStrategyFoundError
 
@@ -89,6 +90,12 @@ def pytest_configure(config):
         env = Environment(config_file=lg_env)
         if lg_coordinator is not None:
             env.config.set_option('coordinator_address', lg_coordinator)
+        # Let the 'proxy' config option override the LG_PROXY environment
+        # variable; a present but empty/false value disables proxying.
+        try:
+            proxymanager.force_proxy(env.config.get_option("proxy"))
+        except KeyError:
+            pass  # no 'proxy' option: keep the LG_PROXY default
     config.stash[LABGRID_ENV_KEY] = env
 
     processwrapper.enable_logging()

labgrid/remote/client.py

@@ -2302,13 +2302,22 @@ def main():
         print("Setting the initial state requires a desired state", file=sys.stderr)
         exit(1)
 
-    if args.proxy:
-        proxymanager.force_proxy(args.proxy)
-
     env = None
     if args.config:
         env = Environment(config_file=args.config)
 
+    # Proxy precedence: --proxy command line argument > 'proxy' config option >
+    # LG_PROXY environment variable (the latter is the proxymanager's default).
+    # A 'proxy' config option that is present but empty/false explicitly
+    # disables proxying, even when LG_PROXY is set.
+    if args.proxy:
+        proxymanager.force_proxy(args.proxy)
+    elif env:
+        try:
+            proxymanager.force_proxy(env.config.get_option("proxy"))
+        except KeyError:
+            pass  # no 'proxy' option: keep the LG_PROXY default
+
     role = None
     if args.command != "reserve" and env and env.config.get_targets():
         if args.place:

labgrid/util/proxy.py

@@ -22,6 +22,11 @@ class ProxyManager:
 
     @classmethod
     def force_proxy(cls, force_proxy):
+        # A falsy value (empty string, None, False) disables proxying, even if
+        # the LG_PROXY environment variable is set.
+        if not force_proxy:
+            cls._force_proxy = None
+            return
         assert isinstance(force_proxy, str)
         cls._force_proxy = force_proxy
 

man/labgrid-device-config.5

@@ -60,6 +60,14 @@ The \fBoptions:\fP top key configures various options such as the coordinator_ad
 .B \fBcoordinator_address\fP
 takes as parameter the coordinator \fBHOST[:PORT]\fP to connect to.
 Defaults to \fB127.0.0.1:20408\fP\&.
+Overrides the \fBLG_COORDINATOR\fP environment variable.
+.TP
+.B \fBproxy\fP
+takes as parameter the SSH proxy host used to tunnel connections to the
+coordinator and to network resources.
+Overrides the \fBLG_PROXY\fP environment variable.
+Set it to an empty value (e.g. \fBproxy:\fP) to force a direct connection
+without a proxy, even when \fBLG_PROXY\fP is set.
 .UNINDENT
 .SS IMAGES
 .sp