Automatic pg_basebackup and wal_archive cleaning

optional/postgresql/Dockerfile

@@ -7,14 +7,18 @@ RUN apk add --no-cache \
 RUN pip3 install jinja2
 # Image specific layers under this line
 RUN apk add --no-cache \
-    postgresql postgresql-libs postgresql-contrib \
+    postgresql postgresql-libs postgresql-contrib busybox-suid \
   && apk add --virtual .build-deps gcc musl-dev postgresql-dev python3-dev \
   && pip3 install psycopg2 anosql \
   && apk --purge del .build-deps
 
 COPY start.py /start.py
+COPY basebackup.sh /basebackup.sh
 COPY conf /conf
 
+COPY postgres_crontab /etc/postgres_crontab
+RUN crontab /etc/postgres_crontab
+
 ENV LANG en_US.UTF-8
 
 RUN mkdir -p /data /backup /run/postgresql \

optional/postgresql/basebackup.sh

@@ -0,0 +1,30 @@
+#!/bin/sh
+
+dest="/backup/base-$(date +%F-%H%M)"
+last=$(ls -d /backup/base* | tail -n1)
+mkdir $dest || exit $?
+
+pg_basebackup --pgdata=$dest --format=tar --gzip --username=postgres || exit $?
+
+# Clean old base backups, keep the last and the current.
+for d in /backup/base*; do
+    if [ "$d" == "$last" ] || [ "$d" == "$dest" ]; then
+        continue
+    fi
+    rm -r $d || exit $?
+done
+
+# Clean the wall archive
+cd /backup/wal_archive || exit $?
+if [ $(ls *.*.backup | wc -l) -lt 2 ]; then
+    ls /backup/wal_archive
+    exit 0
+fi
+# Find the single last wal.backup point
+prev_wal_start="$(ls *.*.backup | tail -n2 | head -n1)"
+for f in $(ls) ; do
+    if [ "$f" \< "$prev_wal_start" ] || [ "$f" \= "$prev_wal_start" ]; then
+        rm -v /backup/wal_archive/$f
+    fi
+done
+ls /backup/wal_archive

optional/postgresql/conf/pg_hba.conf

@@ -85,6 +85,6 @@ host    postgres        health          127.0.0.1/32            md5
 host    all             all             ::1/128                 reject
 # Allow replication connections from localhost, by a user with the
 # replication privilege.
-local   replication     all                                     reject
+local   replication     all                                     peer map=local
 host    replication     all             127.0.0.1/32            reject
 host    replication     all             ::1/128                 reject

optional/postgresql/postgres_crontab

@@ -0,0 +1 @@
+11 4 * * * /basebackup.sh > /proc/1/fd/1 2>/proc/1/fd/2

optional/postgresql/start.py

@@ -5,6 +5,7 @@ import psycopg2
 import jinja2
 import glob
 import os
+import subprocess
 
 def setup():
     conn =  psycopg2.connect(user = 'postgres')
@@ -32,7 +33,6 @@ if not os.path.exists('/data/pg_wal'):
     os.system("su - postgres -c 'initdb -D /data'")
 
 # Create backup directory structure, if it does not yet exist
-os.system("mkdir -p /backup/dump")
 os.system("mkdir -p /backup/wal_archive")
 os.system("chown -R postgres:postgres /backup")
 
@@ -46,5 +46,9 @@ os.system("su - postgres -c 'pg_ctl start -D /data -o \"-h localhost\"'")
 setup()
 os.system("su - postgres -c 'pg_ctl stop -m smart -w -D /data'")
 
+out=open("/proc/1/fd/1", "w")
+err=open("/proc/1/fd/2", "w")
+# Run the cron deamon
+subprocess.Popen(["crond", "-f", "-d7"], stdout=out, stderr=err)
 # Run postgresql service
 os.system("su - postgres -c 'postgres -D /data -h \*'")