Request BACKUP_CUSTOM_LABEL when stop containers.

README.md

@@ -166,10 +166,12 @@ services:
     labels:
       # Adding this label means this container should be stopped while it's being backed up:
       - "docker-volume-backup.stop-during-backup=true"
+      - "grafana"
 
   backup:
     image: jareware/docker-volume-backup
     environment:
+      BACKUP_CUSTOM_LABEL: "grafana"
       AWS_S3_BUCKET_NAME: my-backup-bucket      # S3 bucket which you own, and already exists
       AWS_ACCESS_KEY_ID: ${AWS_ACCESS_KEY_ID}   # Read AWS secrets from environment (or a .env file)
       AWS_SECRET_ACCESS_KEY: ${AWS_SECRET_ACCESS_KEY}

src/backup.sh

@@ -27,11 +27,8 @@ info "Backup starting"
 TIME_START="$(date +%s.%N)"
 DOCKER_SOCK="/var/run/docker.sock"
 
-if [ ! -z "$BACKUP_CUSTOM_LABEL" ]; then
+if [ -S "$DOCKER_SOCK" ] && [ ! -z "$BACKUP_CUSTOM_LABEL" ]; then
   CUSTOM_LABEL="--filter label=$BACKUP_CUSTOM_LABEL"
-fi
-
-if [ -S "$DOCKER_SOCK" ]; then
   TEMPFILE="$(mktemp)"
   docker ps --format "{{.ID}}" --filter "label=docker-volume-backup.stop-during-backup=true" $CUSTOM_LABEL > "$TEMPFILE"
   CONTAINERS_TO_STOP="$(cat $TEMPFILE | tr '\n' ' ')"
@@ -43,7 +40,13 @@ if [ -S "$DOCKER_SOCK" ]; then
 else
   CONTAINERS_TO_STOP_TOTAL="0"
   CONTAINERS_TOTAL="0"
-  echo "Cannot access \"$DOCKER_SOCK\", won't look for containers to stop"
+  if [ ! -S "$DOCKER_SOCK" ]; then
+    echo "Cannot access \"$DOCKER_SOCK\"."
+  fi
+  if [ -z "$BACKUP_CUSTOM_LABEL" ]; then
+    echo "No BACKUP_CUSTOM_LABEL set."
+  fi
+  echo "Thus, won't look for containers to stop."
 fi
 
 if [ "$CONTAINERS_TO_STOP_TOTAL" != "0" ]; then

test/stopping-containers-while-backing-up/docker-compose.yml

@@ -10,11 +10,13 @@ services:
       - grafana-data:/var/lib/grafana
     labels:
       - "docker-volume-backup.stop-during-backup=true"
+      - "grafana"
 
   backup:
     build: ../..
     environment:
       BACKUP_CRON_EXPRESSION: "* * * * *"
+      BACKUP_CUSTOM_LABEL: "grafana"
       AWS_S3_BUCKET_NAME: docker-volume-backup-test-bucket
       AWS_ACCESS_KEY_ID: ${AWS_ACCESS_KEY_ID}
       AWS_SECRET_ACCESS_KEY: ${AWS_SECRET_ACCESS_KEY}