Add shared backup helpers

abra

@@ -3,6 +3,7 @@
 GIT_URL="https://git.autonomic.zone/coop-cloud/"
 ABRA_DIR="${ABRA_DIR:-$HOME/.abra}"
 ABRA_VERSION="0.4.1"
+ABRA_BACKUP_DIR="${ABRA_BACKUP_DIR:-$ABRA_DIR/backups}"
 
 #######################################
 # Global help
@@ -345,6 +346,22 @@ debug() {
   echo "$(tput setaf 13)DEBUG: $*$(tput sgr0)"
 }
 
+# 3wc: temporarily disable debug and verbose
+
+silence() {
+  # FIXME 3wc: required otherwise we get debug output in the password
+  _abra___debug="$abra___debug"
+  _abra___verbose="$abra___verbose"
+  abra___verbose="false"
+  abra___debug="false"
+}
+
+unsilence() {
+  # FIXME 3wc: required otherwise we get debug output in the password
+  abra___verbose="$_abra___verbose"
+  abra___debug="$_abra___debug"
+}
+
 ###### Default settings
 
 if [ -z "$COMPOSE_FILE" ]; then
@@ -777,6 +794,73 @@ sub_app_restore (){
   $FUNCTION "$abra__backup_file_"
 }
 
+###### backup utility functions
+
+# Usage: _abra_backup_dir service:/path/to/src
+_abra_backup_dir() {
+  {
+    abra__src_="$1"
+    abra__dst_="-"
+  }
+
+  # shellcheck disable=SC2154
+  FILENAME="$ABRA_BACKUP_DIR/${abra__app_}_$(basename "$1")_$(date +%F).tar.gz"
+
+  debug "Copying '$1' to '$FILENAME'"
+
+  silence
+  sub_app_cp | gzip > "$FILENAME"
+  success "Backed up '$1' to $FILENAME"
+  unsilence
+}
+
+_abra_backup_db_prep() {
+  # shellcheck disable=SC2034
+  abra__service_="$1"
+  # 3wc: necessary because $abra__service_ won't be set if we're coming from
+  # `abra_backup`, i.e. `abra app ... backup --all`
+
+  # What's the name of the Docker secret? Default to db_root_password
+  DB_PASSWORD_NAME=${4:-db_root_password}
+
+  debug "Looking up secret '$DB_PASSWORD_NAME'"
+  silence
+  DB_PASSWORD="$(sub_app_run cat "/run/secrets/$DB_PASSWORD_NAME")"
+  unsilence
+
+  # 3wc: strip newline \r from variable
+  DB_PASSWORD="${DB_PASSWORD//$'\015'}"
+
+  # shellcheck disable=SC2154
+  FILENAME="$ABRA_BACKUP_DIR/${abra__app_}_$(date +%F).sql.gz"
+}
+
+# usage: _abra_backup_postgres <service> <database> [<user> <secret name>]
+_abra_backup_postgres() {
+  _abra_backup_db_prep "$@"
+
+  debug "Running pg_dump to '$FILENAME'"
+
+  silence
+  # shellcheck disable=SC2034
+  PGPASSWORD="$DB_PASSWORD"
+  sub_app_run pg_dump -U "${3:-postgres}" "$2" | gzip > "$FILENAME"
+  unsilence
+
+  success "Backed up '$abra__service_:$2' to '$FILENAME'"
+}
+
+_abra_backup_mysql() {
+  _abra_backup_db_prep "$@"
+
+  silence
+  # shellcheck disable=SC2086
+  sub_app_run mysqldump -u root -p"${DB_PASSWORD}" "$2" | gzip > "$FILENAME"
+  unsilence
+
+  success "Backed up '$abra__service_:$2' to $FILENAME"
+}
+
 ###### .. app deploy
 help_app_deploy (){
   echo "abra [options] app <app> deploy [--skip-check]