update alpine base image to 3.14

Allow for making container stop filter configurable

Dockerfile

@@ -1,7 +1,7 @@
 # Copyright 2021 - Offen Authors <hioffen@posteo.de>
 # SPDX-License-Identifier: MIT
 
-FROM alpine:3.13
+FROM alpine:3.14
 
 WORKDIR /root
 

README.md

@@ -38,11 +38,39 @@ AWS_S3_BUCKET_NAME="<xxx>"
 
 # BACKUP_RETENTION_DAYS="7"
 
+# In case the duration a backup takes fluctuates noticeably in your setup
+# you can adjust this setting to make sure there are no race conditions
+# between the backup finishing and the pruning not deleting backups that
+# sit on the very edge of the time window. Set this value to a duration
+# that is expected to be bigger than the maximum difference of backups.
+# Valid values have a suffix of (s)econds, (m)inutes, (h)ours, or (d)ays.
+
+# BACKUP_PRUNING_LEEWAY="10m"
+
 ########### BACKUP ENCRYPTION
 
 # Backups can be encrypted using gpg in case a passphrase is given
 
 # GPG_PASSPHRASE="<xxx>"
+
+########### STOPPING CONTAINERS DURING BACKUP
+
+# Containers can be stopped by applying a
+# `docker-volume-backup.stop-during-backup` label. By default, all containers
+# that are labeled with `true` will be stopped. If you need more fine grained
+# control (e.g. when running multiple containers based on this image), you can
+# override this default by specifying a different value here.
+
+# BACKUP_STOP_CONTAINER_LABEL="service1"
+
+########### MINIO CLIENT CONFIGURATION
+
+# Pass these additional flags to all MinIO client `mc` invocations.
+# This can be used for example to pass `--insecure` when using self
+# signed certificates, or passing `--debug` to gain insights on
+# unexpected behavior.
+
+# MC_GLOBAL_OPTIONS="<xxx>"
 ```
 
 ## Example in a docker-compose setup

src/backup.sh

@@ -19,7 +19,7 @@ if [ -S "$DOCKER_SOCK" ]; then
   TEMPFILE="$(mktemp)"
   docker ps \
     --format "{{.ID}}" \
-    --filter "label=docker-volume-backup.stop-during-backup=true" \
+    --filter "label=docker-volume-backup.stop-during-backup=$BACKUP_STOP_CONTAINER_LABEL" \
     > "$TEMPFILE"
   CONTAINERS_TO_STOP="$(cat $TEMPFILE | tr '\n' ' ')"
   CONTAINERS_TO_STOP_TOTAL="$(cat $TEMPFILE | wc -l)"
@@ -58,7 +58,7 @@ fi
 if [ ! -z "$AWS_S3_BUCKET_NAME" ]; then
   info "Uploading backup to remote storage"
   echo "Will upload to bucket \"$AWS_S3_BUCKET_NAME\"."
-  mc cp "$BACKUP_FILENAME" "backup-target/$AWS_S3_BUCKET_NAME"
+  mc cp $MC_GLOBAL_OPTIONS "$BACKUP_FILENAME" "backup-target/$AWS_S3_BUCKET_NAME"
   echo "Upload finished."
 fi
 
@@ -72,16 +72,18 @@ echo "Will wait for next scheduled backup."
 
 if [ ! -z "$BACKUP_RETENTION_DAYS" ]; then
   info "Pruning old backups"
+  echo "Sleeping ${BACKUP_PRUNING_LEEWAY} before checking eligibility."
+  sleep "$BACKUP_PRUNING_LEEWAY"
   bucket=$AWS_S3_BUCKET_NAME
 
-  rule_applies_to=$(mc rm --fake --recursive -force --older-than "${BACKUP_RETENTION_DAYS}d" "backup-target/$bucket" | wc -l)
+  rule_applies_to=$(mc rm $MC_GLOBAL_OPTIONS --fake --recursive -force --older-than "${BACKUP_RETENTION_DAYS}d" "backup-target/$bucket" | wc -l)
   if [ "$rule_applies_to" == "0" ]; then
     echo "No backups found older than the configured retention period of $BACKUP_RETENTION_DAYS days."
     echo "Doing nothing."
     exit 0
   fi
 
-  total=$(mc ls "backup-target/$bucket" | wc -l)
+  total=$(mc ls $MC_GLOBAL_OPTIONS "backup-target/$bucket" | wc -l)
 
   if [ "$rule_applies_to" == "$total" ]; then
     echo "Using a retention of ${BACKUP_RETENTION_DAYS} days would prune all currently existing backups, will not continue."
@@ -89,6 +91,6 @@ if [ ! -z "$BACKUP_RETENTION_DAYS" ]; then
     exit 1
   fi
 
-  mc rm --recursive -force --older-than "${BACKUP_RETENTION_DAYS}d" "backup-target/$bucket"
+  mc rm $MC_GLOBAL_OPTIONS --recursive -force --older-than "${BACKUP_RETENTION_DAYS}d" "backup-target/$bucket"
   echo "Successfully pruned ${rule_applies_to} backups older than ${BACKUP_RETENTION_DAYS} days."
 fi

src/entrypoint.sh

@@ -15,16 +15,21 @@ BACKUP_CRON_EXPRESSION="${BACKUP_CRON_EXPRESSION:-@daily}"
 BACKUP_FILENAME=${BACKUP_FILENAME:-"backup-%Y-%m-%dT%H-%M-%S.tar.gz"}
 
 BACKUP_RETENTION_DAYS="${BACKUP_RETENTION_DAYS:-}"
+BACKUP_PRUNING_LEEWAY="${BACKUP_PRUNING_LEEWAY:-10m}"
 
 AWS_S3_BUCKET_NAME="${AWS_S3_BUCKET_NAME:-}"
 AWS_ENDPOINT="${AWS_ENDPOINT:-s3.amazonaws.com}"
 
 GPG_PASSPHRASE="${GPG_PASSPHRASE:-}"
+
+BACKUP_STOP_CONTAINER_LABEL="${BACKUP_STOP_CONTAINER_LABEL:-true}"
+
+MC_GLOBAL_OPTIONS="${MC_GLOBAL_OPTIONS:-}"
 EOF
 chmod a+x env.sh
 source env.sh
 
-mc alias set backup-target "https://$AWS_ENDPOINT" "$AWS_ACCESS_KEY_ID" "$AWS_SECRET_ACCESS_KEY"
+mc $MC_GLOBAL_OPTIONS alias set backup-target "https://$AWS_ENDPOINT" "$AWS_ACCESS_KEY_ID" "$AWS_SECRET_ACCESS_KEY"
 
 # Add our cron entry, and direct stdout & stderr to Docker commands stdout
 echo "Installing cron.d entry with expression $BACKUP_CRON_EXPRESSION."