From 7806e56eab17de05c25fe6d75077b6c1c6b21bcc Mon Sep 17 00:00:00 2001
From: Frederik Ring <frederik.ring@gmail.com>
Date: Mon, 9 Jun 2025 12:44:40 +0200
Subject: [PATCH 1/3] Add test demonstrating failure when running on worker
 node

---
 test/docker-compose.yml             |  7 ++--
 test/test.sh                        |  9 +++--
 test/worker-node/.multinode         |  1 +
 test/worker-node/docker-compose.yml | 56 +++++++++++++++++++++++++++++
 test/worker-node/run.sh             | 33 +++++++++++++++++
 5 files changed, 102 insertions(+), 4 deletions(-)
 create mode 100644 test/worker-node/.multinode
 create mode 100644 test/worker-node/docker-compose.yml
 create mode 100755 test/worker-node/run.sh

diff --git a/test/docker-compose.yml b/test/docker-compose.yml
index ec7bd698..faec9b38 100644
--- a/test/docker-compose.yml
+++ b/test/docker-compose.yml
@@ -1,5 +1,6 @@
 services:
   manager: &node
+    hostname: manager
     privileged: true
     image: offen/docker-volume-backup:test-sandbox
     healthcheck:
@@ -8,17 +9,19 @@ services:
       timeout: 5s
       retries: 50
     volumes:
-      - $SOURCE:/code
-      - $TARBALL:/cache/image.tar.gz
+      - ./:/code
+      - ${TARBALL:-.}:/cache/image.tar.gz
       - docker_volume_backup_test_sandbox_image:/var/lib/docker/image
       - docker_volume_backup_test_sandbox_overlay2:/var/lib/docker/overlay2
 
   worker1:
     <<: *node
+    hostname: worker1
     profiles:
       - multinode
   worker2:
     <<: *node
+    hostname: worker2
     profiles:
       - multinode
 
diff --git a/test/test.sh b/test/test.sh
index 8d4c0df1..6abdfcd6 100755
--- a/test/test.sh
+++ b/test/test.sh
@@ -46,18 +46,23 @@ for dir in $(find $find_args | sort); do
 
   docker compose --profile $compose_profile up -d --wait
 
+  test_context=manager
   if [ -f "${dir}/.swarm" ]; then
     docker compose exec manager docker swarm init
   elif [ -f "${dir}/.multinode" ]; then
+    test_context=$(cat $dir/.multinode)
+
     docker compose exec manager docker swarm init
     manager_ip=$(docker compose exec manager docker node inspect $(docker compose exec manager docker node ls -q) --format '{{ .Status.Addr }}')
     token=$(docker compose exec manager docker swarm join-token -q worker)
     docker compose exec worker1 docker swarm join --token $token $manager_ip:2377
     docker compose exec worker2 docker swarm join --token $token $manager_ip:2377
+
+    docker compose exec -w "/code/$dir" manager docker stack deploy --compose-file="docker-compose.yml" test_stack
   fi
 
-  docker compose exec manager /bin/sh -c "docker load -i /cache/image.tar.gz"
-  docker compose exec -e TEST_VERSION=$IMAGE_TAG manager /bin/sh -c "/code/test/$test"
+  docker compose exec $test_context /bin/sh -c "docker load -i /cache/image.tar.gz"
+  docker compose exec -e TEST_VERSION=$IMAGE_TAG $test_context /bin/sh -c "/code/$test"
 
   docker compose --profile $compose_profile down
   echo ""
diff --git a/test/worker-node/.multinode b/test/worker-node/.multinode
new file mode 100644
index 00000000..6f352b26
--- /dev/null
+++ b/test/worker-node/.multinode
@@ -0,0 +1 @@
+worker1
diff --git a/test/worker-node/docker-compose.yml b/test/worker-node/docker-compose.yml
new file mode 100644
index 00000000..843d234e
--- /dev/null
+++ b/test/worker-node/docker-compose.yml
@@ -0,0 +1,56 @@
+services:
+  database:
+    image: mariadb:10.7
+    deploy:
+      restart_policy:
+        condition: on-failure
+      placement:
+        constraints:
+          - node.hostname == worker1
+    environment:
+      MARIADB_ROOT_PASSWORD: test
+      MARIADB_DATABASE: backup
+    labels:
+      - docker-volume-backup.archive-pre=/bin/sh -c 'mysqldump -ptest --all-databases > /tmp/volume/dump.sql'
+      - docker-volume-backup.copy-post=/bin/sh -c 'echo "post" > /tmp/volume/post.txt'
+      - docker-volume-backup.stop-during-backup=true
+    volumes:
+      - app_data:/tmp/volume
+
+  other_database:
+    image: mariadb:10.7
+    deploy:
+      placement:
+        constraints:
+          - node.hostname == manager
+      restart_policy:
+        condition: on-failure
+    environment:
+      MARIADB_ROOT_PASSWORD: test
+      MARIADB_DATABASE: backup
+    labels:
+      - docker-volume-backup.archive-pre=touch /tmp/volume/not-relevant.txt
+      - docker-volume-backup.exec-label=not-relevant
+    volumes:
+      - app_data:/tmp/volume
+
+  backup:
+    image: offen/docker-volume-backup:${TEST_VERSION:-canary}
+    deploy:
+      restart_policy:
+        condition: on-failure
+      placement:
+        constraints:
+          - node.hostname == worker1
+    environment:
+      BACKUP_FILENAME: test.tar.gz
+      BACKUP_CRON_EXPRESSION: 0 0 5 31 2 ?
+      EXEC_FORWARD_OUTPUT: "true"
+    volumes:
+      - backup_archive:/archive
+      - app_data:/backup/data:ro
+      - /var/run/docker.sock:/var/run/docker.sock:ro
+
+volumes:
+  app_data:
+  backup_archive:
diff --git a/test/worker-node/run.sh b/test/worker-node/run.sh
new file mode 100755
index 00000000..c47e6881
--- /dev/null
+++ b/test/worker-node/run.sh
@@ -0,0 +1,33 @@
+#!/bin/sh
+
+set -e
+
+cd $(dirname $0)
+. ../util.sh
+current_test=$(basename $(pwd))
+
+export TMP_DIR=$(mktemp -d)
+export LOCAL_DIR=$(mktemp -d)
+
+while [ -z $(docker ps -q -f name=backup) ]; do
+  info "Backup container not ready yet. Retrying."
+  sleep 1
+done
+
+sleep 20
+
+docker exec $(docker ps -q -f name=backup) backup
+
+mkdir -p /archive
+docker cp $(docker ps -q -f name=backup):/archive $LOCAL_DIR
+
+tar -xvf "$LOCAL_DIR/archive/test.tar.gz" -C $TMP_DIR
+if [ ! -f "$TMP_DIR/backup/data/dump.sql" ]; then
+  fail "Could not find file written by pre command."
+fi
+pass "Found expected file."
+
+if [ -f "$TMP_DIR/backup/data/post.txt" ]; then
+  fail "File created in post command was present in backup."
+fi
+pass "Did not find unexpected file."

From 466aa2a869a0f3f81262133f9ccd89bc2bbdfaff Mon Sep 17 00:00:00 2001
From: Frederik Ring <frederik.ring@gmail.com>
Date: Mon, 9 Jun 2025 13:19:58 +0200
Subject: [PATCH 2/3] Consider manager status when checking for swarm related
 features

---
 cmd/backup/stop_restart.go      |  2 +-
 cmd/backup/stop_restart_test.go | 15 ++++++++++++++-
 test/test.sh                    |  9 +++++----
 3 files changed, 20 insertions(+), 6 deletions(-)

diff --git a/cmd/backup/stop_restart.go b/cmd/backup/stop_restart.go
index cfb03525..5b954160 100644
--- a/cmd/backup/stop_restart.go
+++ b/cmd/backup/stop_restart.go
@@ -89,7 +89,7 @@ func isSwarm(c interface {
 	if err != nil {
 		return false, errwrap.Wrap(err, "error getting docker info")
 	}
-	return info.Swarm.LocalNodeState != "" && info.Swarm.LocalNodeState != swarm.LocalNodeStateInactive, nil
+	return info.Swarm.LocalNodeState != "" && info.Swarm.LocalNodeState != swarm.LocalNodeStateInactive && info.Swarm.ControlAvailable, nil
 }
 
 // stopContainersAndServices stops all Docker containers that are marked as to being
diff --git a/cmd/backup/stop_restart_test.go b/cmd/backup/stop_restart_test.go
index 9e907bd7..384ae338 100644
--- a/cmd/backup/stop_restart_test.go
+++ b/cmd/backup/stop_restart_test.go
@@ -30,13 +30,26 @@ func TestIsSwarm(t *testing.T) {
 			&mockInfoClient{
 				result: system.Info{
 					Swarm: swarm.Info{
-						LocalNodeState: swarm.LocalNodeStateActive,
+						LocalNodeState:   swarm.LocalNodeStateActive,
+						ControlAvailable: true,
 					},
 				},
 			},
 			true,
 			false,
 		},
+		{
+			"worker",
+			&mockInfoClient{
+				result: system.Info{
+					Swarm: swarm.Info{
+						LocalNodeState: swarm.LocalNodeStateActive,
+					},
+				},
+			},
+			false,
+			false,
+		},
 		{
 			"compose",
 			&mockInfoClient{
diff --git a/test/test.sh b/test/test.sh
index 6abdfcd6..dc42cd0c 100755
--- a/test/test.sh
+++ b/test/test.sh
@@ -45,13 +45,15 @@ for dir in $(find $find_args | sort); do
   fi
 
   docker compose --profile $compose_profile up -d --wait
-
   test_context=manager
+  if [ -f "${dir}/.multinode" ]; then
+    test_context=$(cat $dir/.multinode)
+  fi
+  docker compose exec $test_context /bin/sh -c "docker load -i /cache/image.tar.gz"
+
   if [ -f "${dir}/.swarm" ]; then
     docker compose exec manager docker swarm init
   elif [ -f "${dir}/.multinode" ]; then
-    test_context=$(cat $dir/.multinode)
-
     docker compose exec manager docker swarm init
     manager_ip=$(docker compose exec manager docker node inspect $(docker compose exec manager docker node ls -q) --format '{{ .Status.Addr }}')
     token=$(docker compose exec manager docker swarm join-token -q worker)
@@ -61,7 +63,6 @@ for dir in $(find $find_args | sort); do
     docker compose exec -w "/code/$dir" manager docker stack deploy --compose-file="docker-compose.yml" test_stack
   fi
 
-  docker compose exec $test_context /bin/sh -c "docker load -i /cache/image.tar.gz"
   docker compose exec -e TEST_VERSION=$IMAGE_TAG $test_context /bin/sh -c "/code/$test"
 
   docker compose --profile $compose_profile down

From 95d6c1151c8145a7c3f581db07f5ae22f57cb78c Mon Sep 17 00:00:00 2001
From: Frederik Ring <frederik.ring@gmail.com>
Date: Mon, 9 Jun 2025 13:55:41 +0200
Subject: [PATCH 3/3] Update documentation

---
 docs/how-tos/use-with-docker-swarm.md | 3 ++-
 test/README.md                        | 8 ++++++++
 test/test.sh                          | 7 +++++--
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/docs/how-tos/use-with-docker-swarm.md b/docs/how-tos/use-with-docker-swarm.md
index 29178551..004f562e 100644
--- a/docs/how-tos/use-with-docker-swarm.md
+++ b/docs/how-tos/use-with-docker-swarm.md
@@ -8,7 +8,8 @@ nav_order: 13
 # Use with Docker Swarm
 
 {: .note }
-The mechanisms described in this page __do only apply when Docker is running in [Swarm mode][swarm]__.
+The mechanisms described in this page __do only apply when Docker is running in [Swarm mode][swarm]__ and __when placing the `docker-volume-backup` container on a manager node__.
+Containers that are placed on worker nodes function as if the Docker engine is not running in Swarm mode, i.e. there is no access to services and there is no way to interact with resources that are running on different host nodes.
 
 [swarm]: https://docs.docker.com/engine/swarm/
 
diff --git a/test/README.md b/test/README.md
index f5b963cb..ce96a323 100644
--- a/test/README.md
+++ b/test/README.md
@@ -67,3 +67,11 @@ A test case can signal it wants to run in swarm mode by placing an empty `.swarm
 In case the swarm setup should be compose of multiple nodes, a `.multinode` file can be used.
 
 A multinode setup will contain one manager (`manager`) and two worker nodes (`worker1` and `worker2`).
+
+If a test is expected to run in the context of a node other than the `manager`, the hostname can be put in the `.multinode` file.
+
+> [!IMPORTANT]
+> When running against a multi-node setup and targeting a non-manager node, the test script will automatically deploy a stack named `test_stack` based on the compose file in the test directory.
+> This is required because the non-manager node cannot deploy the stack itself from within the test script.
+> This also means, you cannot mount local directories created in your test script, as the containers are already created when the script runs.
+> You can work around this limitation by creating named volumes and then `docker cp`ing the contents your test needs to inspect.
diff --git a/test/test.sh b/test/test.sh
index dc42cd0c..dc2c8de2 100755
--- a/test/test.sh
+++ b/test/test.sh
@@ -46,8 +46,9 @@ for dir in $(find $find_args | sort); do
 
   docker compose --profile $compose_profile up -d --wait
   test_context=manager
-  if [ -f "${dir}/.multinode" ]; then
+  if [ -f "${dir}/.multinode" ] && [ -s "${dir}/.multinode" ]; then
     test_context=$(cat $dir/.multinode)
+    echo "Running tests on $test_context instead of manager"
   fi
   docker compose exec $test_context /bin/sh -c "docker load -i /cache/image.tar.gz"
 
@@ -60,7 +61,9 @@ for dir in $(find $find_args | sort); do
     docker compose exec worker1 docker swarm join --token $token $manager_ip:2377
     docker compose exec worker2 docker swarm join --token $token $manager_ip:2377
 
-    docker compose exec -w "/code/$dir" manager docker stack deploy --compose-file="docker-compose.yml" test_stack
+    if [ "$test_context" != "manager" ]; then
+      docker compose exec -w "/code/$dir" manager docker stack deploy --compose-file="docker-compose.yml" test_stack
+    fi
   fi
 
   docker compose exec -e TEST_VERSION=$IMAGE_TAG $test_context /bin/sh -c "/code/$test"