Merge pull request #1 from jan-brinkmann/Add-host-check

Add host check
pietmacom · Sep 4, 2021 · dff874a · dff874a
2 parents 5e0e941 + 8da3c46
commit dff874a
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diff --git a/Dockerfile b/Dockerfile
@@ -1,6 +1,6 @@
 FROM ubuntu:18.04
 
-RUN apt-get update && apt-get install -y --no-install-recommends curl cron ca-certificates unzip
+RUN apt-get update && apt-get install -y --no-install-recommends curl cron ca-certificates iputils-ping unzip
 RUN rm -rf /var/lib/apt/lists/*
 
 # Install awscliv2 https://docs.aws.amazon.com/cli/latest/userguide/install-cliv2-linux.html

diff --git a/README.md b/README.md
@@ -203,6 +203,7 @@ Variable | Default | Notes
 `BACKUP_WAIT_SECONDS` | `0` | The backup script will sleep this many seconds between re-starting stopped containers, and proceeding with archiving/uploading the backup. This can be useful if you don't want the load/network spike of a large upload immediately after the load/network spike of container startup.
 `BACKUP_HOSTNAME` | `$(hostname)` | Name of the host (i.e. Docker container) in which the backup runs. Mostly useful if you want a specific hostname to be associated with backup metrics (see InfluxDB support).
 `BACKUP_CUSTOM_LABEL` |  | When provided, the [start/stop](#stopping-containers-while-backing-up) and [pre/post exec](#prepost-backup-exec) logic only applies to containers with this custom label.
+`CHECK_HOST` |  | When provided, the availability of the named host will be checked. The host should be the destination host of the backups. If the host answers a ping, the backup is conducted as normal. Else, the backup is skipped.
 `AWS_S3_BUCKET_NAME` |  | When provided, the resulting backup file will be uploaded to this S3 bucket after the backup has ran.
 `AWS_GLACIER_VAULT_NAME` |  | When provided, the resulting backup file will be uploaded to this AWS Glacier vault after the backup has ran.
 `AWS_ACCESS_KEY_ID` |  | Required when using `AWS_S3_BUCKET_NAME`.

diff --git a/src/backup.sh b/src/backup.sh
@@ -9,140 +9,158 @@ function info {
   echo -e "\n$bold[INFO] $1$reset\n"
 }
 
-info "Backup starting"
-TIME_START="$(date +%s.%N)"
-DOCKER_SOCK="/var/run/docker.sock"
-
-if [ ! -z "$BACKUP_CUSTOM_LABEL" ]; then
-  CUSTOM_LABEL="--filter label=$BACKUP_CUSTOM_LABEL"
-fi
-
-if [ -S "$DOCKER_SOCK" ]; then
+if [ "$CHECK_HOST" != "false" ]; then
   TEMPFILE="$(mktemp)"
-  docker ps --format "{{.ID}}" --filter "label=docker-volume-backup.stop-during-backup=true" $CUSTOM_LABEL > "$TEMPFILE"
-  CONTAINERS_TO_STOP="$(cat $TEMPFILE | tr '\n' ' ')"
-  CONTAINERS_TO_STOP_TOTAL="$(cat $TEMPFILE | wc -l)"
-  CONTAINERS_TOTAL="$(docker ps --format "{{.ID}}" | wc -l)"
-  rm "$TEMPFILE"
-  echo "$CONTAINERS_TOTAL containers running on host in total"
-  echo "$CONTAINERS_TO_STOP_TOTAL containers marked to be stopped during backup"
+  ping -c 1 $CHECK_HOST | grep '1 packets transmitted, 1 received' > "$TEMPFILE"
+  PING_RESULT="$(cat $TEMPFILE)"
+  if [ ! -z "$PING_RESULT" ]; then
+    skip="false"
+    echo "$CHECK_HOST is available."
+  else
+    skip="true"
+    echo "$CHECK_HOST is not available."
+    info "Backup skipped"
+  fi
 else
-  CONTAINERS_TO_STOP_TOTAL="0"
-  CONTAINERS_TOTAL="0"
-  echo "Cannot access \"$DOCKER_SOCK\", won't look for containers to stop"
+  skip="false"
 fi
 
-if [ "$CONTAINERS_TO_STOP_TOTAL" != "0" ]; then
-  info "Stopping containers"
-  docker stop $CONTAINERS_TO_STOP
-fi
+if [ "$skip" == "false" ]; then
+  info "Backup starting"
+  TIME_START="$(date +%s.%N)"
+  DOCKER_SOCK="/var/run/docker.sock"
 
-if [ -S "$DOCKER_SOCK" ]; then
-  TEMPFILE="$(mktemp)"
-  docker ps \
-    --filter "label=docker-volume-backup.exec-pre-backup" $CUSTOM_LABEL \
-    --format '{{.ID}} {{.Label "docker-volume-backup.exec-pre-backup"}}' \
-    > "$TEMPFILE"
-  while read line; do
-    info "Pre-exec command: $line"
-    docker exec $line
-  done < "$TEMPFILE"
-  rm "$TEMPFILE"
-fi
+  if [ ! -z "$BACKUP_CUSTOM_LABEL" ]; then
+    CUSTOM_LABEL="--filter label=$BACKUP_CUSTOM_LABEL"
+  fi
 
-info "Creating backup"
-BACKUP_FILENAME="$(date +"${BACKUP_FILENAME:-backup-%Y-%m-%dT%H-%M-%S.tar.gz}")"
-TIME_BACK_UP="$(date +%s.%N)"
-tar -czvf "$BACKUP_FILENAME" $BACKUP_SOURCES # allow the var to expand, in case we have multiple sources
-BACKUP_SIZE="$(du --bytes $BACKUP_FILENAME | sed 's/\s.*$//')"
-TIME_BACKED_UP="$(date +%s.%N)"
-
-if [ ! -z "$GPG_PASSPHRASE" ]; then
-  info "Encrypting backup"
-  gpg --symmetric --cipher-algo aes256 --batch --passphrase "$GPG_PASSPHRASE" -o "${BACKUP_FILENAME}.gpg" $BACKUP_FILENAME
-  rm $BACKUP_FILENAME
-  BACKUP_FILENAME="${BACKUP_FILENAME}.gpg"
-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 $TEMPFILE | tr '\n' ' ')"
+    CONTAINERS_TO_STOP_TOTAL="$(cat $TEMPFILE | wc -l)"
+    CONTAINERS_TOTAL="$(docker ps --format "{{.ID}}" | wc -l)"
+    rm "$TEMPFILE"
+    echo "$CONTAINERS_TOTAL containers running on host in total"
+    echo "$CONTAINERS_TO_STOP_TOTAL containers marked to be stopped during backup"
+  else
+    CONTAINERS_TO_STOP_TOTAL="0"
+    CONTAINERS_TOTAL="0"
+    echo "Cannot access \"$DOCKER_SOCK\", won't look for containers to stop"
+  fi
 
-if [ -S "$DOCKER_SOCK" ]; then
-  TEMPFILE="$(mktemp)"
-  docker ps \
-    --filter "label=docker-volume-backup.exec-post-backup" $CUSTOM_LABEL \
-    --format '{{.ID}} {{.Label "docker-volume-backup.exec-post-backup"}}' \
-    > "$TEMPFILE"
-  while read line; do
-    info "Post-exec command: $line"
-    docker exec $line
-  done < "$TEMPFILE"
-  rm "$TEMPFILE"
-fi
+  if [ "$CONTAINERS_TO_STOP_TOTAL" != "0" ]; then
+    info "Stopping containers"
+    docker stop $CONTAINERS_TO_STOP
+  fi
 
-if [ "$CONTAINERS_TO_STOP_TOTAL" != "0" ]; then
-  info "Starting containers back up"
-  docker start $CONTAINERS_TO_STOP
-fi
+  if [ -S "$DOCKER_SOCK" ]; then
+    TEMPFILE="$(mktemp)"
+    docker ps \
+      --filter "label=docker-volume-backup.exec-pre-backup" $CUSTOM_LABEL \
+      --format '{{.ID}} {{.Label "docker-volume-backup.exec-pre-backup"}}' \
+      > "$TEMPFILE"
+    while read line; do
+      info "Pre-exec command: $line"
+      docker exec $line
+    done < "$TEMPFILE"
+    rm "$TEMPFILE"
+  fi
 
-info "Waiting before processing"
-echo "Sleeping $BACKUP_WAIT_SECONDS seconds..."
-sleep "$BACKUP_WAIT_SECONDS"
-
-TIME_UPLOAD="0"
-TIME_UPLOADED="0"
-if [ ! -z "$AWS_S3_BUCKET_NAME" ]; then
-  info "Uploading backup to S3"
-  echo "Will upload to bucket \"$AWS_S3_BUCKET_NAME\""
-  TIME_UPLOAD="$(date +%s.%N)"
-  aws $AWS_EXTRA_ARGS s3 cp --only-show-errors "$BACKUP_FILENAME" "s3://$AWS_S3_BUCKET_NAME/"
-  echo "Upload finished"
-  TIME_UPLOADED="$(date +%s.%N)"
-fi
-if [ ! -z "$AWS_GLACIER_VAULT_NAME" ]; then
-  info "Uploading backup to GLACIER"
-  echo "Will upload to vault \"$AWS_GLACIER_VAULT_NAME\""
-  TIME_UPLOAD="$(date +%s.%N)"
-  aws $AWS_EXTRA_ARGS glacier upload-archive --account-id - --vault-name "$AWS_GLACIER_VAULT_NAME" --body "$BACKUP_FILENAME"
-  echo "Upload finished"
-  TIME_UPLOADED="$(date +%s.%N)"
-fi
+  info "Creating backup"
+  BACKUP_FILENAME="$(date +"${BACKUP_FILENAME:-backup-%Y-%m-%dT%H-%M-%S.tar.gz}")"
+  TIME_BACK_UP="$(date +%s.%N)"
+  tar -czvf "$BACKUP_FILENAME" $BACKUP_SOURCES # allow the var to expand, in case we have multiple sources
+  BACKUP_SIZE="$(du --bytes $BACKUP_FILENAME | sed 's/\s.*$//')"
+  TIME_BACKED_UP="$(date +%s.%N)"
+
+  if [ ! -z "$GPG_PASSPHRASE" ]; then
+    info "Encrypting backup"
+    gpg --symmetric --cipher-algo aes256 --batch --passphrase "$GPG_PASSPHRASE" -o "${BACKUP_FILENAME}.gpg" $BACKUP_FILENAME
+    rm $BACKUP_FILENAME
+    BACKUP_FILENAME="${BACKUP_FILENAME}.gpg"
+  fi
 
-if [ -d "$BACKUP_ARCHIVE" ]; then
-  info "Archiving backup"
-  mv -v "$BACKUP_FILENAME" "$BACKUP_ARCHIVE/$BACKUP_FILENAME"
-  if (($BACKUP_UID > 0)); then
-    chown -v $BACKUP_UID:$BACKUP_GID "$BACKUP_ARCHIVE/$BACKUP_FILENAME"
+  if [ -S "$DOCKER_SOCK" ]; then
+    TEMPFILE="$(mktemp)"
+    docker ps \
+      --filter "label=docker-volume-backup.exec-post-backup" $CUSTOM_LABEL \
+      --format '{{.ID}} {{.Label "docker-volume-backup.exec-post-backup"}}' \
+      > "$TEMPFILE"
+    while read line; do
+      info "Post-exec command: $line"
+      docker exec $line
+    done < "$TEMPFILE"
+    rm "$TEMPFILE"
   fi
-fi
 
-if [ -f "$BACKUP_FILENAME" ]; then
-  info "Cleaning up"
-  rm -vf "$BACKUP_FILENAME"
-fi
+  if [ "$CONTAINERS_TO_STOP_TOTAL" != "0" ]; then
+    info "Starting containers back up"
+    docker start $CONTAINERS_TO_STOP
+  fi
+
+  info "Waiting before processing"
+  echo "Sleeping $BACKUP_WAIT_SECONDS seconds..."
+  sleep "$BACKUP_WAIT_SECONDS"
+
+  TIME_UPLOAD="0"
+  TIME_UPLOADED="0"
+  if [ ! -z "$AWS_S3_BUCKET_NAME" ]; then
+    info "Uploading backup to S3"
+    echo "Will upload to bucket \"$AWS_S3_BUCKET_NAME\""
+    TIME_UPLOAD="$(date +%s.%N)"
+    aws $AWS_EXTRA_ARGS s3 cp --only-show-errors "$BACKUP_FILENAME" "s3://$AWS_S3_BUCKET_NAME/"
+    echo "Upload finished"
+    TIME_UPLOADED="$(date +%s.%N)"
+  fi
+  if [ ! -z "$AWS_GLACIER_VAULT_NAME" ]; then
+    info "Uploading backup to GLACIER"
+    echo "Will upload to vault \"$AWS_GLACIER_VAULT_NAME\""
+    TIME_UPLOAD="$(date +%s.%N)"
+    aws $AWS_EXTRA_ARGS glacier upload-archive --account-id - --vault-name "$AWS_GLACIER_VAULT_NAME" --body "$BACKUP_FILENAME"
+    echo "Upload finished"
+    TIME_UPLOADED="$(date +%s.%N)"
+  fi
 
-info "Collecting metrics"
-TIME_FINISH="$(date +%s.%N)"
-INFLUX_LINE="$INFLUXDB_MEASUREMENT\
-,host=$BACKUP_HOSTNAME\
+  if [ -d "$BACKUP_ARCHIVE" ]; then
+    info "Archiving backup"
+    mv -v "$BACKUP_FILENAME" "$BACKUP_ARCHIVE/$BACKUP_FILENAME"
+    if (($BACKUP_UID > 0)); then
+      chown -v $BACKUP_UID:$BACKUP_GID "$BACKUP_ARCHIVE/$BACKUP_FILENAME"
+    fi
+  fi
+
+  if [ -f "$BACKUP_FILENAME" ]; then
+    info "Cleaning up"
+    rm -vf "$BACKUP_FILENAME"
+  fi
+
+  info "Collecting metrics"
+  TIME_FINISH="$(date +%s.%N)"
+  INFLUX_LINE="$INFLUXDB_MEASUREMENT\
+  ,host=$BACKUP_HOSTNAME\
 \
- size_compressed_bytes=$BACKUP_SIZE\
+size_compressed_bytes=$BACKUP_SIZE\
 ,containers_total=$CONTAINERS_TOTAL\
 ,containers_stopped=$CONTAINERS_TO_STOP_TOTAL\
 ,time_wall=$(perl -E "say $TIME_FINISH - $TIME_START")\
 ,time_total=$(perl -E "say $TIME_FINISH - $TIME_START - $BACKUP_WAIT_SECONDS")\
 ,time_compress=$(perl -E "say $TIME_BACKED_UP - $TIME_BACK_UP")\
 ,time_upload=$(perl -E "say $TIME_UPLOADED - $TIME_UPLOAD")\
 "
-echo "$INFLUX_LINE" | sed 's/ /,/g' | tr , '\n'
-
-if [ ! -z "$INFLUXDB_URL" ]; then
-  info "Shipping metrics"
-  curl \
-    --silent \
-    --include \
-    --request POST \
-    --user "$INFLUXDB_CREDENTIALS" \
-    "$INFLUXDB_URL/write?db=$INFLUXDB_DB" \
-    --data-binary "$INFLUX_LINE"
-fi
+  echo "$INFLUX_LINE" | sed 's/ /,/g' | tr , '\n'
+
+  if [ ! -z "$INFLUXDB_URL" ]; then
+    info "Shipping metrics"
+    curl \
+      --silent \
+      --include \
+      --request POST \
+      --user "$INFLUXDB_CREDENTIALS" \
+      "$INFLUXDB_URL/write?db=$INFLUXDB_DB" \
+      --data-binary "$INFLUX_LINE"
+  fi
 
-info "Backup finished"
-echo "Will wait for next scheduled backup"
+  info "Backup finished"
+fi
+  echo "Will wait for next scheduled backup"
diff --git a/src/entrypoint.sh b/src/entrypoint.sh
@@ -22,6 +22,7 @@ INFLUXDB_DB="${INFLUXDB_DB:-}"
 INFLUXDB_CREDENTIALS="${INFLUXDB_CREDENTIALS:-}"
 INFLUXDB_MEASUREMENT="${INFLUXDB_MEASUREMENT:-docker_volume_backup}"
 BACKUP_CUSTOM_LABEL="${BACKUP_CUSTOM_LABEL:-}"
+CHECK_HOST="${CHECK_HOST:-"false"}"
 EOF
 chmod a+x env.sh
 source env.sh

diff --git a/test/backing-up-check-host/docker-compose.yml b/test/backing-up-check-host/docker-compose.yml
@@ -0,0 +1,22 @@
+version: "3"
+
+services:
+
+  dashboard:
+    image: grafana/grafana
+    ports:
+      - "3000:3000"
+    volumes:
+      - grafana-data:/var/lib/grafana
+
+  backup:
+    build: ../..
+    environment:
+      BACKUP_CRON_EXPRESSION: "* * * * *"
+      CHECK_MOUNT: "192.168.0.2" # The script sends a ping to 192.168.0.2. If the host answers the ping, the backup starts. Otherwise, it is skipped. You can als provide a hostname that is resolved by means of DNS.
+    volumes:
+      - grafana-data:/backup/grafana-data:ro
+      - ./backups:/archive
+
+volumes:
+  grafana-data: