Add better Docker development and prod support

.docker/release/files/logrotate-loop.sh

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+#!/bin/bash
+# ----------------------------------------------------------------------
+# Simple script to invoke logrotate at regular intervals
+# ----------------------------------------------------------------------
+
+# from https://github.com/misho-kr/docker-appliances/blob/master/nginx-nodejs/logrotate-loop.sh
+
+LOGROTATE_BIN="logrotate"
+
+STATE="$HOME/logrotate.state"
+CONF="/etc/logrotate.d/snappymail"
+
+export LOGROTATE_BIN STATE CONF
+
+RUN_INTERVAL="3600"     # every hour
+
+# helper functions for logging
+export FMT="%a %b %d %Y %H:%M:%S GMT%z (%Z)"
+
+function log_date() {
+    echo "$(date +"$FMT"): $*"
+}
+
+# ----------------------------------------------------------------------
+# Main loop of the logrotate service:
+#
+#   while True:
+#       sleep N seconds
+#       run logrotate
+#
+# ----------------------------------------------------------------------
+
+function logrotate_loop() {
+
+    trap on_terminate TERM INT
+
+    local interval="${1}"
+
+    log_date "===================================================="
+    log_date
+    log_date "logrotate service starting (pid=$$)"
+    log_date "logrotate process will run every ${interval} seconds"
+
+    while true; do
+
+        current_time=$(date "+%s")
+        next_run_time=$(( current_time + interval ))
+
+        while (( current_time < next_run_time  ))
+        do
+            logrotate_sleep $(( next_run_time - current_time ))
+            current_time=$(date "+%s")
+        done
+
+        logrotate_run
+    done
+}
+
+# helper function to execute logrotate and pass it the right parameters
+function logrotate_run() {
+
+    log_date "logrotate will run now"
+    ${LOGROTATE_BIN} -s ${STATE} ${CONF}
+}
+
+# ----------------------------------------------------------------------
+# Procedure to idle the execution for a number of seconds
+#
+# There are two requirements:
+#
+#   - export the PID of the sleep command so that it can be terminated
+#     in case the logrotate service is being shutdown
+#   - keep this (bash) process responsive to SIGTERM while in sleep
+#     mode (normally the signal will be masked and will not be delivered
+#     until the subprocess completes)
+# ----------------------------------------------------------------------
+
+proc_sleep_pid=""
+
+function logrotate_sleep() {
+
+    local sleep_interval=${1}
+
+    log_date "logrotate will sleep for ${sleep_interval} seconds"
+
+    ( exec -a "logrotate: sleep" sleep ${sleep_interval} )&
+
+    proc_sleep_pid=$!
+    wait ${proc_sleep_pid}
+}
+
+# ----------------------------------------------------------------------
+# Signal handler for logrotate service to make sure the process exits:
+#
+#   - properly by terminating the sleep process that is used to idle
+#     the service
+#   - gracefully by writing a message in the log
+# ----------------------------------------------------------------------
+
+function on_terminate() {
+
+    log_date "logrotate will terminate"
+    log_date
+
+    kill -TERM ${proc_sleep_pid}
+    exit 0
+}
+
+# ----------------------------------------------------------------------
+#  main
+# ----------------------------------------------------------------------
+
+logrotate_loop ${1:-RUN_INTERVAL}