Get rid of hard coded IPs (#441)

Replace them with:
* containers' hostnames
* gateway's IP address for default SMTP_HOST
* Core: when SMTP_HOST undef, echo the default value
* docker-compose: add port mapping
* docker-compose: drop network driver conf
* Exim macro: use localhost as LMTP host
* Update README.md
* docker-compose: Limit port mapping to loopback
* Update other docker-compose example files

web/README.md

@@ -43,11 +43,12 @@ change them unless you know what you want.
 - `MAILMAN_REST_PASSWORD`: Mailman's REST API user's password. Default value is
   `restpass`
 
-- `MAILMAN_HOST_IP`: IP of the Container from which Mailman will send emails to
-  hyperkitty (django). Set to `172.19.199.2` by default.
+- `MAILMAN_HOSTNAME`: IP of the Container from which Mailman will send emails to
+  hyperkitty (django). Set to `mailman-core` by default.
 
 - `SMTP_HOST`: IP Address/hostname from which you will be sending
-  emails. Default value is `172.19.199.1`, which is the address of the Host OS.
+  emails. Default value is the container's gateway retrieved from:
+    /sbin/ip route | awk '/default/ { print $3 }'
 
 - `SMTP_PORT`: Port used for SMTP. Default is `25`.
 

web/docker-entrypoint.sh

@@ -53,6 +53,11 @@ function check_or_create () {
 # END
 # }
 
+# SMTP_HOST defaults to the gateway
+if [[ ! -v SMTP_HOST ]]; then
+	export SMTP_HOST=$(/sbin/ip route | awk '/default/ { print $3 }')
+fi
+
 # Check if $SECRET_KEY is defined, if not, bail out.
 if [[ ! -v SECRET_KEY ]]; then
 	echo "SECRET_KEY is not defined. Aborting."

web/mailman-web/settings.py

@@ -29,6 +29,7 @@ https://docs.djangoproject.com/en/1.8/ref/settings/
 import os
 import dj_database_url
 import sys
+from socket import gethostbyname
 
 BASE_DIR = os.path.dirname(os.path.abspath(__file__))
 
@@ -51,7 +52,7 @@ ALLOWED_HOSTS = [
     # "lists.your-domain.org",
     # Add here all production URLs you may have.
     "mailman-web",
-    "172.19.199.3",
+    gethostbyname("mailman-web"),
     os.environ.get('SERVE_FROM_DOMAIN'),
     os.environ.get('DJANGO_ALLOWED_HOSTS'),
 ]
@@ -61,7 +62,7 @@ MAILMAN_REST_API_URL = os.environ.get('MAILMAN_REST_URL', 'http://mailman-core:8
 MAILMAN_REST_API_USER = os.environ.get('MAILMAN_REST_USER', 'restadmin')
 MAILMAN_REST_API_PASS = os.environ.get('MAILMAN_REST_PASSWORD', 'restpass')
 MAILMAN_ARCHIVER_KEY = os.environ.get('HYPERKITTY_API_KEY')
-MAILMAN_ARCHIVER_FROM = (os.environ.get('MAILMAN_HOST_IP', '172.19.199.2'),)
+MAILMAN_ARCHIVER_FROM = (os.environ.get('MAILMAN_HOST_IP', gethostbyname(os.environ.get('MAILMAN_HOSTNAME', 'mailman-core'))),)
 
 # Application definition
 
@@ -227,7 +228,7 @@ SERVER_EMAIL = 'root@{}'.format(hostname)
 
 # Change this when you have a real email backend
 EMAIL_BACKEND = 'django.core.mail.backends.smtp.EmailBackend'
-EMAIL_HOST = os.environ.get('SMTP_HOST', '172.19.199.1')
+EMAIL_HOST = os.environ.get('SMTP_HOST', '')
 EMAIL_PORT = os.environ.get('SMTP_PORT', 25)
 EMAIL_HOST_USER = os.environ.get('SMTP_HOST_USER', '')
 EMAIL_HOST_PASSWORD = os.environ.get('SMTP_HOST_PASSWORD', '')