Adding test and check for resolv.conf

Signed-off-by: Adam Hill <adam@diginc.us>

CHANGELOG.md

@@ -0,0 +1,5 @@
+# Docker Pi-Hole changelog
+
+Notes about releases will be documented on [docker-pi-hole's github releases page](https://github.com/pi-hole/docker-pi-hole/releases).  Breaking changes will be copied to the top of the docker repo's README file to assist with common upgrade issues.
+
+See the [Pi-hole releases](https://github.com/pi-hole/pi-hole/releases) for details on updates unreleated to docker image releases

README.md

@@ -12,7 +12,7 @@ Starting with the v4.1.1 release your Pi-hole container may encounter issues sta
 - `--cap-add=NET_ADMIN` This previously optional argument is now required or strongly encouraged
   - Starting in version 4.1.2 FTL, the DNS Service, is going to check this setting automatically
 - `--dns=127.0.0.1 --dns=1.1.1.1` The second server can be any DNS IP of your choosing, but the **first dns must be 127.0.0.1**
-  - A WARNING stating "resolv.conf misconfiguration, see v4.1.1 release notes" may show in docker logs without this.
+  - A WARNING stating "Misconfigured DNS in /etc/resolv.conf" may show in docker logs without this.
 
 These are the raw [docker run cli](https://docs.docker.com/engine/reference/commandline/cli/) versions of the commands.  We provide no official support for docker GUIs but the community forums may be able to help if you do not see a place for these settings.  Remember, always consult your manual too!
  

bash_functions.sh

@@ -1,7 +1,28 @@
 #!/bin/bash
 
 docker_checks() {
-    echo hi
+    warn_msg='WARNING Misconfigured DNS in /etc/resolv.conf'
+    ns_count="$(grep -c nameserver /etc/resolv.conf)"
+    ns_primary="$(grep nameserver /etc/resolv.conf | head -1)"
+    ns_primary="${ns_primary/nameserver /}"
+    warned=false
+
+    if [ "$ns_count" -lt 2 ] ; then
+        echo "$warn_msg: Two DNS servers are recommended, 127.0.0.1 and any backup server"
+        warned=true
+    fi
+
+    if [ "$ns_primary" != "127.0.0.1" ] ; then
+        echo "$warn_msg: Primary DNS should be 127.0.0.1 (found ${ns_primary})"
+        warned=true
+    fi
+
+    if ! $warned ; then
+        echo "OK: Checks passed for /etc/resolv.conf DNS servers"
+    fi
+
+    echo
+    cat /etc/resolv.conf
 }
 
 prepare_configs() {

test/test_bash_functions.py

@@ -179,5 +179,17 @@ def test_webPassword_env_assigns_password_to_file_or_removes_if_empty(Docker, ar
 
 
 
-def test_docker_checks_for_resolvconf_misconfiguration(Docker):
-    pass
+@pytest.mark.parametrize('args_dns, expected_stdout', [
+    # No DNS passed will vary by the host this is ran on, bad idea for a test
+    #('', 'WARNING Misconfigured DNS in /etc/resolv.conf: Primary DNS should be 127.0.0.1'),
+    ('--dns 1.1.1.1',                 'WARNING Misconfigured DNS in /etc/resolv.conf: Two DNS servers are recommended, 127.0.0.1 and any backup server\n'
+                                      'WARNING Misconfigured DNS in /etc/resolv.conf: Primary DNS should be 127.0.0.1 (found 1.1.1.1)'),
+    ('--dns 127.0.0.1',               'WARNING Misconfigured DNS in /etc/resolv.conf: Two DNS servers are recommended, 127.0.0.1 and any backup server'),
+    ('--dns 1.1.1.1 --dns 127.0.0.1', 'WARNING Misconfigured DNS in /etc/resolv.conf: Primary DNS should be 127.0.0.1 (found 1.1.1.1)'),
+    ('--dns 127.0.0.1 --dns 1.1.1.1', 'OK: Checks passed for /etc/resolv.conf DNS servers'),
+])
+def test_docker_checks_for_resolvconf_misconfiguration(Docker, args_dns, expected_stdout):
+    ''' The container checks for misconfigured resolv.conf '''
+    function = Docker.run('. /bash_functions.sh ; eval `grep docker_checks /start.sh`')
+    print function.stdout
+    assert expected_stdout in function.stdout