Add option -r for executing restic

The new option -r allows executing any restic command with the
repository and password settings specified in the configuration file.

mpbackup

@@ -37,17 +37,18 @@ unset_restic_vars
 options = {}
 options[:config_names] = []
 options[:prune] = false
+options[:run_restic] = false
 
 OptionParser.new do |parser|
   parser.on("-c NAME", "--configuration-name NAME", "Name of the configuration to use") do |v|
     options[:config_names] << v
   end
 
-  parser.on("-f CONFIG_FILE", "--config-file CONFIG_FILE", "Path to the configuration file") do |v|
+  parser.on("-f CONFIG_FILE", "--config-file CONFIG_FILE", "Path to the configuration file.") do |v|
     options[:config_file] = v
   end
 
-  parser.on("-h", "--help", "Print this help") do
+  parser.on("-h", "--help", "Print this help.") do
       puts parser
       exit
   end
@@ -56,7 +57,14 @@ OptionParser.new do |parser|
     options[:prune] = v
   end
 
-  parser.on('--version', "Print version number") do
+  parser.on('-r', '--run-restic', 'Set environment variables '\
+    'RESTIC_REPOSITORY and RESTIC_PASSWORD, execute restic (while passing '\
+    'all following command line arguments to restic).') do |v|
+    options[:run_restic] = v
+    parser.terminate
+  end
+
+  parser.on('--version', "Print version number.") do
     puts "#{NAME}, #{VERSION}"
     exit
   end
@@ -83,9 +91,6 @@ def check
 end
 
 def backup(config)
-  puts "Applying configuration ‘#{config['name']}’ …"
-  set_restic_vars(config)
-
   puts "Backing up with restic …"
   # https://restic.readthedocs.io/en/latest/040_backup.html#including-and-excluding-files
   exclude = config.dig('backup', 'exclude')&.flat_map{|e| ['--exclude', e]} || []
@@ -117,9 +122,6 @@ def backup(config)
 end
 
 def prune(config)
-  puts "Applying configuration ‘#{config['name']}’ …"
-  set_restic_vars(config)
-
   puts 'Pruning restic repo …'
   prune_command = ['restic', 'prune']
   puts("Command: #{prune_command.join(' ')}")
@@ -131,17 +133,32 @@ def prune(config)
   check
 end
 
+def run_restic(config)
+  puts 'Executing restic with the following arguments …'
+  puts "ARGV: #{ARGV}"
+  exec('restic', *ARGV)
+end
+
+def act(config, options)
+  puts "Applying configuration ‘#{config['name']}’ …"
+  set_restic_vars(config)
+  if options[:prune]
+    prune config
+  elsif options[:run_restic]
+    run_restic config
+  else
+    backup config
+  end
+  unset_restic_vars
+end
+
 puts "Using config file #{config_file} …"
 configs = YAML.load_stream(File.open(config_file))
 config_names = options[:config_names]
 if config_names.empty?
   puts "No configuration name has been given. Will use the first "\
     "configuration from the file (‘#{configs.dig(0, 'name')}’)."
-  if options[:prune]
-    prune configs[0]
-  else
-    backup configs[0]
-  end
+  act(configs[0], options)
 else
   config_hash = configs.map {|c| [c['name'], c]}.to_h
   config_names.each do |name|
@@ -150,11 +167,6 @@ else
     end
   end
   config_names.each do |config_name|
-    config = config_hash[config_name]
-    if options[:prune]
-      prune config
-    else
-      backup config
-    end
+    act(config_hash[config_name], options)
   end
 end