Fix handling of empty directories (#44)

* Add test checking whether empty directories are included in backups

* Update targz library to include fix

README.md

@@ -123,10 +123,10 @@ You can populate below template according to your requirements and use it as you
 # BACKUP_FILENAME="backup-%Y-%m-%dT%H-%M-%S.tar.gz"
 
 # Setting BACKUP_FILENAME_EXPAND to true allows for environment variable
-# placeholders in BACKUP_FILENAME and in BACKUP_LATEST_SYMLINK that will get
-# expanded at runtime, e.g. `backup-$HOSTNAME-%Y-%m-%dT%H-%M-%S.tar.gz`.
-# Expansion happens before interpolating strftime tokens.
-# It is disabled by default.
+# placeholders in BACKUP_FILENAME, BACKUP_LATEST_SYMLINK and in
+# BACKUP_PRUNING_PREFIX that will get expanded at runtime,
+# e.g. `backup-$HOSTNAME-%Y-%m-%dT%H-%M-%S.tar.gz`. Expansion happens before
+# interpolating strftime tokens. It is disabled by default.
 # Please note that you will need to escape the `$` when providing the value
 # in a docker-compose.yml file, i.e. using $$VAR instead of $VAR.
 

cmd/backup/main.go

@@ -157,6 +157,7 @@ func newScript() (*script, error) {
 	if s.c.BackupFilenameExpand {
 		s.file = os.ExpandEnv(s.file)
 		s.c.BackupLatestSymlink = os.ExpandEnv(s.c.BackupLatestSymlink)
+		s.c.BackupPruningPrefix = os.ExpandEnv(s.c.BackupPruningPrefix)
 	}
 	s.file = timeutil.Strftime(&s.start, s.file)
 

go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/gofrs/flock v0.8.1
 	github.com/kelseyhightower/envconfig v1.4.0
 	github.com/leekchan/timeutil v0.0.0-20150802142658-28917288c48d
-	github.com/m90/targz v0.0.0-20210904082215-2e9a4529a615
+	github.com/m90/targz v0.0.0-20211229090208-2f22c2d9278e
 	github.com/minio/minio-go/v7 v7.0.16
 	github.com/otiai10/copy v1.7.0
 	github.com/sirupsen/logrus v1.8.1

go.sum

@@ -450,8 +450,8 @@ github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/leekchan/timeutil v0.0.0-20150802142658-28917288c48d h1:2puqoOQwi3Ai1oznMOsFIbifm6kIfJaLLyYzWD4IzTs=
 github.com/leekchan/timeutil v0.0.0-20150802142658-28917288c48d/go.mod h1:hO90vCP2x3exaSH58BIAowSKvV+0OsY21TtzuFGHON4=
 github.com/leodido/go-urn v1.2.0/go.mod h1:+8+nEpDfqqsY+g338gtMEUOtuK+4dEMhiQEgxpxOKII=
-github.com/m90/targz v0.0.0-20210904082215-2e9a4529a615 h1:rn0LO2tQEgCDOct8qnbcslTUpAIWdVlWcGkjoumhf2U=
-github.com/m90/targz v0.0.0-20210904082215-2e9a4529a615/go.mod h1:YZK3bSO/oVlk9G+v00BxgzxW2Us4p/R4ysHOBjk0fJI=
+github.com/m90/targz v0.0.0-20211229090208-2f22c2d9278e h1:Kzm2zfxS40RUGD5UVtVtOo9RT5TtGoNJnmWORtCEaxM=
+github.com/m90/targz v0.0.0-20211229090208-2f22c2d9278e/go.mod h1:YZK3bSO/oVlk9G+v00BxgzxW2Us4p/R4ysHOBjk0fJI=
 github.com/magiconair/properties v1.8.0/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
 github.com/magiconair/properties v1.8.1/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
 github.com/mailru/easyjson v0.0.0-20190403194419-1ea4449da983/go.mod h1:C1wdFJiN94OJF2b5HbByQZoLdCWB1Yqtg26g4irojpc=

test/cli/run.sh

@@ -7,6 +7,7 @@ cd $(dirname $0)
 docker network create test_network
 docker volume create backup_data
 docker volume create app_data
+docker volume create empty_data
 
 docker run -d \
   --name minio \
@@ -31,6 +32,7 @@ sleep 10
 docker run --rm \
   --network test_network \
   -v app_data:/backup/app_data \
+  -v empty_data:/backup/empty_data \
   -v /var/run/docker.sock:/var/run/docker.sock \
   --env AWS_ACCESS_KEY_ID=test \
   --env AWS_SECRET_ACCESS_KEY=GMusLtUmILge2by+z890kQ \
@@ -44,7 +46,7 @@ docker run --rm \
 
 docker run --rm -it \
   -v backup_data:/data alpine \
-  ash -c 'tar -xvf /data/backup/test.tar.gz && test -f /backup/app_data/offen.db'
+  ash -c 'tar -xvf /data/backup/test.tar.gz && test -f /backup/app_data/offen.db && test -d /backup/empty_data'
 
 echo "[TEST:PASS] Found relevant files in untared backup."