bitbucket -> gitlab

bitbucket2gitlab.rb

#!/usr/bin/ruby

# --                                                            ; {{{1
#
# File        : bitbucket2gitlab.rb
# Maintainer  : Felix C. Stegerman <[email protected]>
# Date        : 2014-07-17
#
# Copyright   : Copyright (C) 2014  Felix C. Stegerman
# Licence     : GPLv3+
#
# Description:
#
#   bitbucket2gitlab - copy bitbucket teams to gitlab groups
#
#   bitbucket2gitlab copies all repositories from each specified
#   BitBucket team to the specified (existing) GitLab group.
#
#   GitLab groups are specified by path (instead of name).
#   Repositories are cloned and pushed via ssh.
#
#   BitBucket password and GitLab token can be specified via
#   $BB_PASSWORD and $GL_TOKEN; when not specified, bitbucket2gitlab
#   will prompt for them.
#
# Caveats:
#
#   bitbucket2gitlab cannot overwrite an existing repository with an
#   empty one; it will leave the existing repository as-is.
#
# Options:
#
#   $ bitbucket2gitlab --help
#
# Dependencies:
#
#   $ gem install excon obfusk-util
#
# TODO:
#
#   * issues?
#   * wikis?
#   * github?
#   * *<->*?
#   * gem?
#
# --                                                            ; }}}1

require 'excon'
require 'json'
require 'obfusk/util/term'
require 'optparse'
require 'tmpdir'

module BitBucket2GitLab
  class Error < RuntimeError; end

  OUT         = Obfusk::Util::Term

  INFO        = 'bitbucket2gitlab - copy bitbucket teams to gitlab groups'
  USAGE       = 'bitbucket2gitlab [<option(s)>] [<bb_team>[:<gl_group>] ...]'

  BB_URL_BASE = 'https://bitbucket.org/api/2.0'
  GL_URL_BASE = -> srv { "https://#{srv}/api/v3" }

  BB_REPO_URL = -> team, repo { "[email protected]:#{team}/#{repo}.git" }
  GL_REPO_URL = -> srv { -> grp, repo { "git@#{srv}:#{grp}/#{repo}.git" } }

  def self.sys(*args)
    puts "$ #{args*' '}"
    Kernel.system(*args).tap do
      $?.success? or raise Error, "#{args*' '} returned #$?"
    end
  end

  def self.sys_out(cmd)
    %x[ #{cmd} ].tap { $?.success? or raise Error, "#{cmd} returned #$?" }
  end

  def self.check_repo_name(t, r)
    t =~ /\A[a-z_][a-z0-9_-]*\z/ or raise Error,
      "team #{t} has a problematic name"
    r =~ /\A[a-z_][a-z0-9_-]*\z/ or raise Error,
      "repository #{t}/#{r} has a problematic name"
  end

  def self.auth_for(which, auth)
    which == :bb ? { user: auth[:user], password: auth[:pass] } :
                   { headers: { 'PRIVATE-TOKEN' => auth[:token] } }
  end

  def self.link_header_next_page(r, d)
    (l = r.headers['Link']) ?
      (n = l.split(',').grep(/rel="next"/).first) ?
        n.match(/<(.*)>/)[1] : nil : nil
  end

  def self.bb_next_page(r, d)
    d['next']
  end

  def self.get(which, url, auth, opts = {})
    one = opts[:one]; pag = opts[:pag] || method(:link_header_next_page)
    ds  = []        ; u   = url
    while true
      puts "GET #{u}"
      r = Excon.get u, auth_for(which, auth).merge(expects: [200])
      ds << d = JSON.parse(r.body); u = pag[r,d] || break
    end
    one ? ds.first : ds
  end

  def self.post(which, url, body, auth)
    puts "POST #{url} << #{body}"
    Excon.post url, auth_for(which, auth).merge(expects: [201], body: body)
  end

  def self.bb_team_repos(team, auth)
    pag = method :bb_next_page
    get(:bb, "#{BB_URL_BASE}/repositories/#{team}", auth, pag: pag) \
      .map { |x| x['values'] } .flatten(1)
  end

  def self.bb_team_repos_names(team, auth)
    bb_team_repos(team, auth).map { |r| r['full_name'].split('/')[1] }
  end

  def self.bb_clone_repo(team, dir, repo)
    args = %w{ git clone --bare } + [BB_REPO_URL[team, repo], "#{repo}.git"]
    sys(*args, chdir: dir)
  end

  def self.gl_groups(auth)
    @gl_groups ||= \
      get(:gl, "#{GL_URL_BASE[auth[:server]]}/groups", auth).flatten(1)
  end

  def self.gl_group_id_for(grp, auth)
    gl_groups(auth).find { |g| g['path'] == grp } ['id']
  end

  def self.gl_group(grp_id, auth)
    @gl_groups_data ||= {}
    @gl_groups_data[grp_id] ||= \
      get(:gl, "#{GL_URL_BASE[auth[:server]]}/groups/#{grp_id}",
          auth, one: true)
  end

  def self.gl_group_repos_names(grp_id, auth)
    gl_group(grp_id, auth)['projects'].map { |r| r['path'] }
  end

  def self.gl_create_repo(grp_id, repo, auth)
    body = URI.encode_www_form(name: repo, namespace_id: grp_id)
    post(:gl, "#{GL_URL_BASE[auth[:server]]}/projects", body, auth)
  end

  def self.gl_push_repo(grp, dir, repo, url_base)
    Dir.chdir("#{dir}/#{repo}.git") do
      if sys_out('git branch -a').empty?
        puts '(empty repository -- nothing to push)'
      else
        args = %w{ git push --mirror } + [url_base[grp, repo]]
        sys(*args)
      end
    end
  end

  def self.configure(*args)
    os  = { gl_server: 'gitlab.com', wait: 10 }
    op  = OptionParser.new(USAGE) do |o|
      o.on('-u', '--bitbucket-user NAME', 'BitBucket user name') do |x|
        os[:bb_user] = x
      end
      o.on('-s', '--gitlab-server HOST',
           'GitLab server; defaults to gitlab.com') do |x|
        os[:gl_srv] = x
      end
      o.on('-k', '--skip', 'Skip existing repo; defaults to no') do
        os[:skip] = true
      end
      o.on('-o', '--overwrite', 'Overwrite existing repo; defaults to no') do
        os[:overwrite] = true
      end
      o.on('-a', '--ask', 'Ask whether to overwrite repo; defaults to no') do
        os[:ask] = true
      end
      o.on('-c', '--continue', 'Continue on errors; defaults to no') do
        os[:continue] = true
      end
      o.on('-w', '--wait SECS', Integer,
           'Wait SECS seconds after creating repo; defaults to 10') do |x|
        os[:wait] = x
      end
      o.on_tail('-h', '--help', 'Show this message') do
        puts INFO, '', o; exit
      end
    end
    begin
      op.parse! args
    rescue OptionParser::ParseError => e
      $stderr.puts "Error: #{e}"; exit 1
    end
    unless os[:bb_user]
      $stderr.puts 'BitBucket user required'; exit 1
    end
    if os.values_at(:skip, :overwrite, :ask).count { |x| x } > 1
      $stderr.puts 'You can only have one of --skip, --overwrite, --ask'
      exit 1
    end
    os[:bb_pass] = ENV['BB_PASSWORD'] ||
                   OUT.prompt('bitbucket password: ', :hide)
    os[:gl_tok]  = ENV['GL_TOKEN'] ||
                   OUT.prompt('gitlab token: ', :hide)
    os[:bb_auth] = { user:   os[:bb_user] , pass:  os[:bb_pass] }
    os[:gl_auth] = { server: os[:gl_srv]  , token: os[:gl_tok]  }
    os[:copy]    = args.map { |x| x.split(':', 2) } \
                       .map { |f,t| { from: f, to: t || f } }
    os
  end

  def self.choose_overwrite_skip_error(os, grp, repos, r)
    msg = "repository #{grp}/#{r} already exists"
    return :create    unless repos.include? r
    return :skip      if os[:skip]
    return :overwrite if os[:overwrite]
    raise Error, msg  unless os[:ask]
    OUT.prompt("#{msg}; overwrite? [y/N] ") =~ /^Y/i ? :overwrite : :skip
  end

  def self.main(*args)
    os = configure(*args)
    os[:copy].each do |c|
      bb_team   = c[:from]; gl_grp = c[:to]
      bb_repos  = bb_team_repos_names   bb_team   , os[:bb_auth]
      gl_grp_id = gl_group_id_for       gl_grp    , os[:gl_auth]
      gl_repos  = gl_group_repos_names  gl_grp_id , os[:gl_auth]
      Dir.mktmpdir do |t|
        bb_repos.each do |r|
          begin
            check_repo_name bb_team, r
            choice = choose_overwrite_skip_error os, gl_grp, gl_repos, r
            next if choice == :skip
            bb_clone_repo bb_team, t, r
            if choice == :create
              gl_create_repo gl_grp_id, r, os[:gl_auth]
              if os[:wait] > 0
                puts '(let server breathe...)'; sleep os[:wait]
              end
            end
            gl_push_repo gl_grp, t, r, GL_REPO_URL[os[:gl_srv]]
          rescue Error, Excon::Errors::Error => e
            puts "*** ERROR: #{e} ***"; exit 1 unless os[:continue]
          end
        end
      end
    end
  end
end

BitBucket2GitLab.main(*ARGV)

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