Add option to prune instead of backing up

mpbackup

@@ -8,7 +8,16 @@ DEFAULT_CONFIG_FILE = Pathname.new('/etc/mpbackup/config.yaml')
 NAME = 'mpbackup'
 VERSION = '0.1.0'
 
-def set_restic_vars(repo, password)
+def set_restic_vars(config)
+  repo = config['repository']
+  puts "Repository: #{repo}"
+  if config['password-file']
+    puts "Reading password from file #{config['password-file']} …"
+    password = File.open(config['password-file'], &:gets).chomp
+  else
+    password = STDIN.getpass('Please put in your restic password: ')
+  end
+
   ENV['RESTIC_REPOSITORY'] = repo
   ENV['RESTIC_PASSWORD'] = password
 end
@@ -27,6 +36,7 @@ unset_restic_vars
 
 options = {}
 options[:config_names] = []
+options[:prune] = false
 
 OptionParser.new do |parser|
   parser.on("-c NAME", "--configuration-name NAME", "Name of the configuration to use") do |v|
@@ -42,6 +52,10 @@ OptionParser.new do |parser|
       exit
   end
 
+  parser.on('-p', '--prune', 'Prunes the repository. Does NOT do anything else.') do |v|
+    options[:prune] = v
+  end
+
   parser.on('--version', "Print version number") do
     puts "#{NAME}, #{VERSION}"
     exit
@@ -58,17 +72,19 @@ if !Pathname.new(config_file).exist? then
   error(1, "Config file #{config_file} has not been found!")
 end
 
-def do_backup(config)
-  puts "Applying configuration ‘#{config['name']}’ …"
-  repo = config['repository']
-  puts "Repository: #{repo}"
-  if config['password-file']
-    puts "Reading password from file #{config['password-file']} …"
-    password = File.open(config['password-file'], &:gets).chomp
-  else
-    password = STDIN.getpass('Please put in your restic password: ')
+def check
+  puts 'Checking restic repo …'
+  check_command = ['restic', 'check']
+  puts("Command: #{check_command.join(' ')}")
+  system(*check_command)
+  if $?.exitstatus > 0
+    error(1, "Checking restic repository #{ENV['RESTIC_REPOSITORY']} failed.")
   end
-  set_restic_vars(repo, password)
+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
@@ -81,13 +97,7 @@ def do_backup(config)
     error(1, 'Failed to do backup.')
   end
 
-  puts 'Checking restic repo …'
-  check_command = ['restic', 'check']
-  puts("Command: #{check_command.join(' ')}")
-  system(*check_command)
-  if $?.exitstatus > 0
-    error(1, "Checking restic repository #{ENV['RESTIC_REPOSITORY']} failed.")
-  end
+  check
 
   if config.dig('forget', 'enable')
     puts 'Forgetting unnecessary snapshots …'
@@ -106,13 +116,28 @@ def do_backup(config)
   unset_restic_vars
 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(' ')}")
+  system(*prune_command)
+  if $?.exitstatus > 0
+    error(1, 'Failed to prune.')
+  end
+
+  check
+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')}’)."
-  do_backup(configs[0])
+  backup configs[0]
 else
   config_hash = configs.map {|c| [c['name'], c]}.to_h
   config_names.each do |name|
@@ -121,6 +146,11 @@ else
     end
   end
   config_names.each do |config_name|
-    do_backup(config_hash[config_name])
+    config = config_hash[config_name]
+    if options[:prune]
+      prune config
+    else
+      backup config
+    end
   end
 end