brew-postgresql-upgrade-database: add new command.

cmd/brew-postgresql-data-upgrade.rb

@@ -0,0 +1,103 @@
+#:  * `postgresql-upgrade-database`:
+#:    Upgrades the database for the `postgresql` formula.
+
+name = "postgresql"
+pg = Formula[name]
+bin = pg.bin
+var = pg.var
+version = pg.version
+pg_version_file = var/"postgres/PG_VERSION"
+
+pg_version_installed = version.to_s[/^\d+/]
+pg_version_data = pg_version_file.read.chomp
+if pg_version_installed == pg_version_data
+  odie <<~EOS
+    #{name} data already upgraded!
+  EOS
+end
+
+datadir = var/"postgres"
+old_datadir = var/"postgres.old"
+if old_datadir.exist?
+  odie <<~EOS
+    #{old_datadir} already exists!
+    Remove it if you want to upgrade data automatically.
+  EOS
+end
+
+old_bin = Pathname.glob("#{HOMEBREW_PREFIX}/Cellar/#{name}{,@#{pg_version_data}}/#{pg_version_data}.*/bin").first
+old_bin ||= begin
+  old_pg_name = "#{name}@#{pg_version_data}"
+  Formula[old_pg_name]
+  ohai "brew install #{old_pg_name}"
+  system "brew", "install", old_pg_name
+  Pathname.glob("#{HOMEBREW_PREFIX}/Cellar/#{old_pg_name}/#{pg_version_data}.*/bin").first
+rescue FormulaUnavailableError
+  nil
+end
+
+odie "No #{name} #{pg_version_data}.* version installed!" unless old_bin
+
+server_stopped = false
+moved_data = false
+initdb_run = false
+upgraded = false
+
+begin
+  # Following instructions from:
+  # https://www.postgresql.org/docs/10/static/pgupgrade.html
+  ohai "Upgrading #{name} data from #{pg_version_data} to #{pg_version_installed}..."
+
+  if /#{name}\s+started/ =~ Utils.popen_read("brew", "services", "list")
+    system "brew", "services", "stop", name
+    service_stopped = true
+  elsif quiet_system "#{bin}/pg_ctl", "-D", datadir, "status"
+    system "#{bin}/pg_ctl", "-D", datadir, "stop"
+    server_stopped = true
+  end
+
+  ohai "Moving #{name} data from #{datadir} to #{old_datadir}..."
+  FileUtils.mv datadir, old_datadir
+  moved_data = true
+
+  (var/"postgres").mkpath
+  system "#{bin}/initdb", "#{var}/postgres"
+  initdb_run = true
+
+  (var/"log").cd do
+    system "#{bin}/pg_upgrade",
+      "-r",
+      "-b", old_bin,
+      "-B", bin,
+      "-d", old_datadir,
+      "-D", datadir,
+      "-j", Hardware::CPU.cores.to_s
+  end
+  upgraded = true
+
+  ohai "Upgraded #{name} data from #{pg_version_data} to #{pg_version_installed}!"
+  ohai "Your #{name} #{pg_version_data} data remains at #{old_datadir}"
+ensure
+  if upgraded
+    if server_stopped
+      safe_system "#{bin}/pg_ctl", "-D", datadir, "start"
+    elsif service_stopped
+      safe_system "brew", "services", "start", name
+    end
+  else
+    onoe "Upgrading #{name} data from #{pg_version_data} to #{pg_version_installed} failed!"
+    if initdb_run
+      ohai "Removing empty #{name} initdb database..."
+      FileUtils.rm_r datadir
+    end
+    if moved_data
+      ohai "Moving #{name} data back from #{old_datadir} to #{datadir}..."
+      FileUtils.mv old_datadir, datadir
+    end
+    if server_stopped
+      system "#{bin}/pg_ctl", "-D", datadir, "start"
+    elsif service_stopped
+      system "brew", "services", "start", name
+    end
+  end
+end