Module: Que::Migrations

Defined in:
lib/que/migrations.rb

Constant Summary collapse

CURRENT_VERSION =

In order to ship a schema change, add the relevant up and down sql files to the migrations directory, and bump the version here.

4

Class Method Summary collapse

Class Method Details

.db_version ⇒ Object 



39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
 
# File 'lib/que/migrations.rb', line 39

def db_version
  result =
    Que.execute <<-SQL
      SELECT relname, description
      FROM pg_class
      LEFT JOIN pg_description ON pg_description.objoid = pg_class.oid
      WHERE relname = 'que_jobs'
    SQL

  if result.none?
    # No table in the database at all.
    0
  elsif (d = result.first[:description]).nil?
    # There's a table, it was just created before the migration system
    # existed.
    1
  else
    d.to_i
  end
end

.migrate!(version:) ⇒ Object 



10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
 
# File 'lib/que/migrations.rb', line 10

def migrate!(version:)
  Que.transaction do
    current = db_version

    if current == version
      return
    elsif current < version
      direction = :up
      steps = ((current + 1)..version).to_a
    elsif current > version
      direction = :down
      steps = ((version + 1)..current).to_a.reverse
    end

    steps.each do |step|
      filename = [
        File.dirname(__FILE__),
        'migrations',
        step,
        direction,
      ].join('/') << '.sql'

      Que.execute(File.read(filename))
    end

    set_db_version(version)
  end
end

.set_db_version(version) ⇒ Object 



60
61
62
63
 
# File 'lib/que/migrations.rb', line 60

def set_db_version(version)
  i = version.to_i
  Que.execute "COMMENT ON TABLE que_jobs IS '#{i}'" unless i.zero?
end