Allow auto detection of bridge networks

maggie44 · maggie44 · commit da1d3eaafc2e · 2022-02-19T00:05:49.000Z
diff --git a/Dockerfile.template b/Dockerfile.template
@@ -41,5 +41,5 @@ COPY --from=python-buildstep /root/.local /root/.local
 # Insert application
 COPY src .
 
-# Check for database migrations then launch controller
-CMD ["python3", "run.py"]
+# Run the start script
+CMD ["sh", "start.sh"]
diff --git a/README.md b/README.md
@@ -39,7 +39,9 @@ If you would prefer to only allow access from your backend, change the `PWC_HOST
 
 Users will then be unable to access the API `http://your-device:9090/v1/connect`. Your backend container on the device, however, can reach the API using `http://127.0.0.1:9090/v1/connect`. This is useful if your user interface has a login process, and you only want users to be able to interact with Wi-Fi after logging in.
 
-Alternatively, if you would rather have your backend use specified ports instead of the host network, you can change the `PWC_HOST` environment variable to `172.17.0.1` and access the API from `http://172.17.0.1:9090/v1/connect`.
+Alternatively, if you would rather have your backend use specified ports instead of the host network, you can change the `PWC_HOST` environment variable to `172.17.0.1` and access the API from `http://172.17.0.1:9090/v1/connect`. On some devices, the default `172.17.0.1` address can not be guaranteed. You can therefore set `PWC_HOST` to `bridge` and it will detect the default Balena Engine bridge on startup and listen on that IP. You wil then need to identify the IP in your other container in order to communicate. The following command in a shell script will get you the IP:
+
+`ip route | awk '/default / { print $3 }'`
 
 ## Changing the default network interface
 
diff --git a/balena.yml b/balena.yml
@@ -11,4 +11,4 @@ assets:
   logo:
     type: blob.asset
     data:
-      url: "https://github.com/maggie0002/balena-py-wifi-connect/main/logo.png"
+      url: "https://raw.githubusercontent.com/maggie0002/balena-py-wifi-connect/main/logo.png"
diff --git a/logo.png b/logo.png
diff --git a/src/.env_vars b/src/.env_vars
@@ -0,0 +1,4 @@
+#!/usr/bin/env
+
+# Exports the current bridge network IP address
+export BRIDGE_NETWORK_IP=$(ip route | awk '/br-/ { print $7 }')
diff --git a/src/common/wifi.py b/src/common/wifi.py
@@ -14,12 +14,6 @@
 from time import sleep
 
 
-# Import DBus mainloop for NetworkManager use
-from dbus.mainloop.glib import DBusGMainLoop
-
-DBusGMainLoop(set_as_default=True)
-
-
 def analyse_access_point(ap):
     security = config.type_none
 
diff --git a/src/config.py b/src/config.py
@@ -13,7 +13,9 @@
     hotspot_password = None
 
 # Set default host.
-if "PWC_HOST" in os.environ:
+if "PWC_HOST" in os.environ and os.environ["PWC_HOST"].lower() == "bridge":
+    host = os.environ["BRIDGE_NETWORK_IP"]
+elif "PWC_HOST" in os.environ:
     host = os.environ["PWC_HOST"]
 else:
     host = "0.0.0.0"
diff --git a/src/run.py b/src/run.py
@@ -71,4 +71,5 @@
         else:
             connect()
 
+    logger.info(f"Listening on {host} port {port}")
     serve(app, host=host, port=port)
diff --git a/src/start.sh b/src/start.sh
@@ -0,0 +1,7 @@
+#!/usr/bin/env
+
+# Import env variables
+. .env_vars
+
+# Execute Python script
+exec python3 -u run.py
