Use Debian Slim as base image

.github/workflows/master.yml

@@ -185,7 +185,7 @@ jobs:
           cache-from: type=local,src=/tmp/.buildx-cache/debian,mode=max,compression=estargz
           cache-to: type=local,dest=/tmp/.buildx-cache-new/debian
           build-args: |
-            BASE_IMAGE=debian:bookworm
+            BASE_IMAGE=debian:bookworm-slim
 
       - name: Move cache
         run: |

.github/workflows/tags.yml

@@ -206,7 +206,7 @@ jobs:
           cache-from: type=local,src=/tmp/.buildx-cache/debian,mode=max,compression=estargz
           cache-to: type=local,dest=/tmp/.buildx-cache-new/debian
           build-args: |
-            BASE_IMAGE=debian:bookworm
+            BASE_IMAGE=debian:bookworm-slim
 
       - name: Move cache
         run: |

Dockerfile

@@ -1,6 +1,6 @@
 # syntax=docker/dockerfile:1.2
 
-ARG BASE_IMAGE=debian:latest
+ARG BASE_IMAGE=debian:bookworm-slim
 # ARG BASE_IMAGE=ubuntu:jammy
 
 FROM ${BASE_IMAGE} AS build-scripts
@@ -65,4 +65,3 @@ HEALTHCHECK --interval=30s --timeout=5s --start-period=10s --retries=3 CMD print
 
 EXPOSE     587
 CMD        [ "/bin/sh", "-c", "/scripts/run.sh" ]
-

build-scripts/postfix-install.sh

@@ -18,6 +18,7 @@ do_ubuntu() {
     if [ "${ID}" = "debian" ]; then
         RELEASE_SPECIFIC_PACKAGES="netcat-openbsd"
     fi
+    export DEBCONF_NOWARNINGS=yes
     export DEBIAN_FRONTEND=noninteractive
     echo "Europe/Berlin" > /etc/timezone
     apt-get update -y -q
@@ -25,6 +26,8 @@ do_ubuntu() {
     apt-get install -y postfix
     apt-get install -y opendkim
     apt-get install -y ca-certificates tzdata supervisor rsyslog bash opendkim-tools curl libcurl4 libjsoncpp25 sasl2-bin postfix-lmdb logrotate cron net-tools ${RELEASE_SPECIFIC_PACKAGES}
+    apt-get clean
+    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*    
 }
 
 if [ -f /etc/alpine-release ]; then