majic-scripts Changeset

Changeset - 58349059257f

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Branko Majic (branko) - 4 years ago 2020-07-06 14:44:41
branko@majic.rs

Noticket: Deduplicate locking code in Factorio Manager:

- Introduce helper function for cleaning-up any registered locks.
- Introduce helper function for calling flock that exits in case of an
error as well.
- Make existing code use the new locking function.

1 file changed with 62 insertions and 65 deletions:

games/factorio_manager.sh

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games/factorio_manager.sh

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@@ @@ -1077,6 +1077,63 @@ function select_factorio_version() { @@
     return 0
+}
+#
 # Removes all registered lock files. Lock files are registered via the
 # global array variable "lock_files". This function is meant to be
 # used in conjunction with trap built-in to clean-up the files on exit.
+#
 # Arguments (globals):
+#
 #   lock_files
 #     Array listing all the lock files that should be removed.
+#
 function remove_lock_files() {
     local lock
     for lock in "${lock_files[@]}"; do
         rm -f "$lock"
     done
+}
 declare -a lock_files=()
 trap remove_lock_files EXIT
+#
 # Acquires an exclusive lock via flock call using the specified file
 # and file descriptor. If it is not possible to acquire a lock,
 # terminates the script, and registers the lock file for removal.
+#
 # The function should be used in conjunction with subshell as follows:
+#
 # (
 #     lock "$HOME/.mylock" 200
+#
 #     do_my_stuff_here
+#
 # ) 200>"$HOME/.mylock"
+#
+#
 # Arguments:
+#
 # $1 (lock_file)
 #   Path to lock file.
+#
 # $2 (fd)
 #   File descriptor number to use for the lock.
+#
 function lock() {
     local lock_file="$1"
     local fd="$2"
     lock_files+=("$lock_file")
     # Obtain lock - Factorio uses the same mechanism, so we should
     # be able to detect the game is running in this way.
     flock --exclusive --nonblock "$fd"
     if [[ $? != 0 ]]; then
         error "Could not acquire lock via lock file '$lock_file'. Is Factorio still running?"
         exit "$ERROR_GENERAL"
     fi
+}
 # Define error codes.
 SUCCESS=0
@@ @@ -1392,19 +1449,7 @@ elif [[ $command == backup ]]; then @@
+    (
         # Obtain lock - Factorio uses the same mechanism, so we should
         # be able to detect the game is running in this way.
         flock --exclusive --nonblock 200
         if [[ $? != 0 ]]; then
             error "Could not lock instance directory via lock file $lock_file. Is Factorio instance still running?"
             exit "$ERROR_GENERAL"
         fi
         function remove_lock() {
             rm "$lock_file"
+        }
         trap remove_lock EXIT
         lock "$lock_file" 200
         # Backup the instance. Clean-up the backup destination in case of failure.
         mkdir -p "$backup_destination"
@@ @@ -1525,18 +1570,7 @@ elif [[ $command == restore ]]; then @@
     validate_path_or_terminate "backup_directory" "$restore_source" "$ERROR_ARGUMENTS"
+    (
         # Obtain lock - Factorio uses the same mechanism, so we should
         # be able to detect the game is running in this way.
         flock --exclusive --nonblock 200
         if [[ $? != 0 ]]; then
             error "Could not lock instance directory via lock file $lock_file. Is Factorio instance still running?"
             exit "$ERROR_GENERAL"
         fi
         function remove_lock() {
             rm "$lock_file"
+        }
         trap remove_lock EXIT
         lock "$lock_file" 200
         # Set-up a list of files and directories that will get removed.
         shopt -s nullglob
@@ @@ -1883,20 +1917,7 @@ elif [[ $command == remove ]]; then @@
     validate_path_or_terminate "instance_directory" "$instance_directory" "$ERROR_ARGUMENTS"
+    (
         # Obtain lock - Factorio uses the same mechanism, so we should
         # be able to detect the game is running in this way.
         flock --exclusive --nonblock 200
         if [[ $? != 0 ]]; then
             error "Could not lock instance directory via lock file $lock_file. Is Factorio instance still running?"
             exit "$ERROR_GENERAL"
         fi
         # Removing lock file will most likely fail if we manage to
         # remove the instance.
         function remove_lock() {
             rm -f "$lock_file"
+        }
         trap remove_lock EXIT
         lock "$lock_file" 200
         # Set-up a list of files and directories that will get removed.
         shopt -s nullglob dotglob
@@ @@ -1999,19 +2020,7 @@ elif [[ $command == copy ]]; then @@
     validate_path_or_terminate "instance_directory_new" "$destination_instance_directory" "$ERROR_ARGUMENTS"
+    (
         # Obtain lock - Factorio uses the same mechanism, so we should
         # be able to detect the game is running in this way.
         flock --exclusive --nonblock 200
         if [[ $? != 0 ]]; then
             error "Could not lock instance directory via lock file $source_lock_file. Is Factorio instance still running?"
             exit "$ERROR_GENERAL"
         fi
         function remove_lock() {
             rm "$source_lock_file"
+        }
         trap remove_lock EXIT
         lock "$source_lock_file" 200
         # Load source instance configuration.
         source "$source_instance_config"
@@ @@ -2123,19 +2132,7 @@ elif [[ $command == import ]]; then @@
+    (
         # Obtain lock - Factorio uses the same mechanism, so we should
         # be able to detect the game is running in this way.
         flock --exclusive --nonblock 200
         if [[ $? != 0 ]]; then
             error "Could not lock instance directory via lock file $source_lock_file. Is Factorio instance still running?"
             exit "$ERROR_GENERAL"
         fi
         function remove_lock() {
             rm "$source_lock_file"
+        }
         trap remove_lock EXIT
         lock "$source_lock_file" 200
         # Create instance directory.
         mkdir "$instance_directory"

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