1 files changed, 60 insertions, 0 deletions
diff --git a/db/migrate/20161207231626_add_environment_slug.rb b/db/migrate/20161207231626_add_environment_slug.rb
new file mode 100644
index 00000000000..7153e6a32b1
--- /dev/null
+++ b/db/migrate/20161207231626_add_environment_slug.rb
@@ -0,0 +1,60 @@
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddEnvironmentSlug < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = true
+  DOWNTIME_REASON = 'Adding NOT NULL column environments.slug with dependent data'
+
+  # Used to generate random suffixes for the slug
+  NUMBERS = '0'..'9'
+  SUFFIX_CHARS = ('a'..'z').to_a + NUMBERS.to_a
+
+  def up
+    environments = Arel::Table.new(:environments)
+
+    add_column :environments, :slug, :string
+    finder = environments.project(:id, :name)
+
+    connection.exec_query(finder.to_sql).rows.each do |id, name|
+      updater = Arel::UpdateManager.new(ActiveRecord::Base).
+        table(environments).
+        set(environments[:slug] => generate_slug(name)).
+        where(environments[:id].eq(id))
+
+      connection.exec_update(updater.to_sql, self.class.name, [])
+    end
+
+    change_column_null :environments, :slug, false
+  end
+
+  def down
+    remove_column :environments, :slug
+  end
+
+  # Copy of the Environment#generate_slug implementation
+  def generate_slug(name)
+    # Lowercase letters and numbers only
+    slugified = name.to_s.downcase.gsub(/[^a-z0-9]/, '-')
+
+    # Must start with a letter
+    slugified = "env-" + slugified if NUMBERS.cover?(slugified[0])
+
+    # Maximum length: 24 characters (OpenShift limitation)
+    slugified = slugified[0..23]
+
+    # Cannot end with a "-" character (Kubernetes label limitation)
+    slugified = slugified[0..-2] if slugified[-1] == "-"
+
+    # Add a random suffix, shortening the current string if necessary, if it
+    # has been slugified. This ensures uniqueness.
+    slugified = slugified[0..16] + "-" + random_suffix if slugified != name
+
+    slugified
+  end
+
+  def random_suffix
+    (0..5).map { SUFFIX_CHARS.sample }.join
+  end
+end