Upgrades and migrations

Upgrades and
Migrations, how?
David Lanier
@nadavoid
ThinkShout
Sunday, October 6, 13

Overview
• Getting your Drupal 6 site onto Drupal 7
• Use traditional upgrade or migrate data to
new site
• Look at the beneﬁts and drawbacks of both
approaches
Your site is unique, so take what you ﬁnd today and let it help you in your decision making. I
won't be saying always do it one way.
Both approaches do require work.

An Architecture
Metaphor
• Changing the foundation (codebase) of
your house
Do you lift the house and swap out the foundation?
Or do you build a new house on a new foundation, then move your stuff in?

Basic pieces
• Codebase (core, modules, themes, libraries)
• Database
• Files (images, pdfs, mp3s, etc.)
Files = content.
Database & Files together = "data"

Upgrade overview
• Swap out the foundation, house in place.
• Replace codebase, run upgrade scripts on
existing data & ﬁles.
• Built into core and contrib.
• UI based
Lift the house, swap in a new foundation, set the house down on the new foundation.
The upgrade scripts essentially upgrade the plumbing and wiring to be compatible with the
new foundation.
UI centered, but drush can be used for most upgrades as well. 'drush updb'

Migrate overview
• Build new house on a new foundation.
• Build new site. Import data from old site.
• Write custom code to deﬁne the speciﬁcs
of the migration.
The details of a migration must be handled by writing custom code. There is also helpful
support in the UI.

Feeds
• Best ﬁt is to regularly import new data.
• Not usually a good ﬁt for full migrations.
• It is easy to learn, but it usually falls short
when getting into the details, such as
handling relationships and very large
datasets.
I really like feeds, and it can be super for importing data into Drupal. But it's just not a
module I generally recommend for a full site migration.

Which way do I go?
• Why do you want to go?
First thing to think about is why speciﬁcally do you want to move to Drupal 7?
Are there architectural things that need to be changed in your site, in order to take advantage
of what you want from D7?

Traditional upgrade if:
• Drupal site, only one version back
• Simple site
• Few contrib modules
• End result should mirror current site
• Content is infrequently updated
• A little downtime is OK
Downtime can still be avoided, using good deployment methods.
Also, if limited time is available (and the other conditions are met).

Traditional upgrade
downsides
• Hard to get rid of legacy cruft
• Field names
• Content type structures
• Anything else that seems old or odd

Migrate if:
• Drupal 5 site, or even a different platform
• Complex site
• Many contrib modules
• New site needs structural changes or
enhancements
• Content is frequently updated
• Minimal downtime is very important

Migrate downsides
• Very code-centric
• Very granular
Averse to custom coding? Maybe prefer upgrade. But Migrate isn't so hard, I promise!
Granular: you generally have to specify everything (image alt, title, language, etc.). Of course,
that could also be a good thing. You're in full control.

Initial preparation
• Regular D7 system requirements
(drupal.org/requirements)
• Local development environment that can
support several copies of the site
D7: PHP 5.3 recommended, MySQL 5.
Local Dev: for testing, experimenting, practicing

Architecture of current
site
• Inventory of modules, libraries, themes
•drush pml | grep Enabled
• Content Types, fields
• Views, other configuration
• Important pages, capabilities, workflows
• Reference copy of the site
Save lists of directories (list of modules)
Save drush output
Save certain pages
Have a clear idea of exactly what it is you're upgrading from

Determine upgrade
path
• Module to D7 options
• same module (pathauto)
• different module
• moved into core (CCK to ﬁelds)
• nothing available, so custom solution
This is where most of the work will be.
Be sure to check if D7 version of modules have their own dependencies. Views adds a ctools
dependency. Others will likely require the libraries module.

Determine upgrade
path
• Custom modules
• Converting 6.x modules to 7.x:
http://drupal.org/node/224333
Any custom code will need to be updated to match the Drupal 7 API and coding standards.

Determine upgrade
path
• Theme
• Update or replace base theme
• Update or rebuild subtheme
• Upgrading 6.x themes to 7.x
https://drupal.org/node/254940
A custom theme is custom code, so needs same attention.

Prepare the source
• Install a copy of the site to use as the
source.
• Remove all disabled or unused modules.
• Update all remaining modules to their
latest D6 versions.

How to Upgrade
• Practice on a copy of the site.
• Pristine copy of site for reference.
• Copy of site with everything D6 updated.
• Copy that is actually getting upgraded.

Today's Example
• RidePDW.com Portland Design Works
• Portland company that develops bicycle
accessories
I experimented with an upgrade, but ended up doing a migration instead.

Process
• Commit after each step.
• Deﬁnitely after updating each module.
• Include db exports.
DB Exports: if not in the repo, in their own folder.

Upgrade Core
• Refer back to your list of all enabled
modules
• Disable all enabled contrib modules
• Switch theme to Garland, including the
admin theme

Upgrade core
• Use the copy of the site that you have for
actually upgrading
• Replace core files manually
• Delete core directories & files
• Add the new ones
• Download Drupal, move the files into
place
I generally prefer to swap in the new files/folders, rather than building up a new codebase.
(List of "incompatible" modules helps me know where I am)

Update the database
• Do 'drush updb'
• Watch output, observe warnings
• Save output to refer back to

Core upgrade
complete!
• Yay!
• You're running Drupal 7 now
• Commit the current state to a repo
• Next step, contrib modules

Upgrading contrib
modules
• Upgrade one at a time
• Module's d.o page
• Module's README.txt or INSTALL.txt or
UPGRADE.txt
• Check for special steps, instructions
• Check for new dependencies
Do a little research on each module before trying. Then go ahead and try.
Dependencies: views needs ctools. ubercart needs rules. rules needs entity.

Add the new code
• This works: drush dl modulename
• Or, delete existing, then add the new

Where to start?
• Start with the most foundational
• ctools
• views
• Or most standalone
• pathauto
• devel

Views
• Replace views code
• Update database
• Enable the upgraded module
This seems to be the usual process. But it's still best to see the module's upgrade
documentation ﬁrst.

Views database updated

Enable views

Upgrade CCK
• Download D7 version of CCK
• Enable the content_migrate module
• Use the UI to migrate CCK fields to drupal
core fields
Kind of a special case, because it's a major architectural change, bringing fields into core.
Also common pattern: contrib module providing upgrade path into core.

Available fields
Provides suggestions of things to do, and notes about what it will do.
Caveat: it lets you migrate fields, even if the relevant content type does not yet exist properly
in the upgraded site. Should content types come before fields?

Converted Fields

Unavailable Fields

Migrate CCK fields
• Install required modules
• Enable modules that define content types
• Sometimes several layers of dependencies
emerge
nodereference is used to refer to products. Products are defined by ubercart. Ubercart
requires Rules. Rules requires entity api.

How to Migrate
• Building a whole new house, with its own
new foundation.
• Then we will move all of our data into it.

Plan and get organized
• Collect data and files into a safe place, to
use as a pristine, read-only source.
• Make a spreadsheet or list to plan out your
mapping
• Build out the architecture of the new site
Identify questionable or troublesome pieces, e.g. whether to keep certain fields.
Build: at least content types & fields.
Anything else that is needed by your migrated data.

Set up environments
• Install or get access to a reference site
• Install source database
• Install a built destination site
• An IDE for exploring the migrate API
reference site = this is how it currently is. must be inspectable.

migrate_d2d
• Not discussing migrate_d2d in depth today.
Not migrate_d2d:
- complicated things for me as a newcomer to the migrate framework.
- Added too many layers and did not streamline things for me.
- Had to unmap many things that it automatically mapped for me.

Start a new module
• Install the migrate module
• Create a new module that extends classes
that are in the migrate module

Important functions
• addFieldMapping()
• addSimpleMappings()
• defaultValue()
• sourceMigration()
• addUnmigratedDestinations()
• addUnmigratedSources()
Just to get a ﬂavor of what you will be using.

Module structure
• .info file: file list
• .module file: specify migrations via
hook_migrate_api()
• Migration class files: handle the details and
mappings of a migration
• name: sitename_migration
.info file: Mainly lists files that are used.
.module file: register migrations and their classes by using hook_migrate_api().
Migration class files: I generally prefer one class per file, but there's nothing wrong with
having multiple classes in one file too.

Directory list

.info ﬁle

.module ﬁle

class ﬁle

How did you ﬁnd out?
• Comments in the migrate module
• migrate_example module (inside migrate)
• articles on btmash.com

Additional Docs
• Source code
• Suggestions in IDE
• Migrate handbook at drupal.org/migrate

Before enabling custom
migrate module

Migration class
• Set description
• Deﬁne database source
• Create query to get data
• Tell migrate that this query is the source of
this migration
• Do the mappings

Set description

Set database

Deﬁne the query

Set the source

Set the destination

Set up table mapping
Enables migrate to map source rows to destination rows

Map ﬁrst ﬁeld

Enable the module
Do live demo of migrating this basic amount, using the UI.
List of migrations & their status.
Status of mappings.
Note equivalent tools in drush.

Mapping process
• Add ﬁelds as needed to the query
• Add mappings until the mapping screen
clear.
Adding ﬁelds will usually mean adding joins.

Mapping a subﬁeld

Mapping a reference
From a ProductHelpMigration

Self references
• Handles creating references to same
import
• Uses a createStub function

Mapping a ﬁle ﬁeld

Term References
• Use a dependent migration
• Or create as needed

Repeats
• "Update" completely overwrites
• Highwater mark
In addition to rollback and reimport.
highwater mark, important for bringing in added content.
brings in any new items with a greater value of highwater than last recorded.
No other comparisons. (no import "changed")

Manipulating source
data
• prepareRow() function

migrate_extras
• Provides support for many contrib modules
• Addressﬁeld, entity api, more
• Excellent examples of custom handlers

Migrate
• Showed important parts
• There's a LOT more there

QA. Did it work?
• Regardless whether upgrade or migrate
• Have someone else check your work
• Have the client check your work
• Pass any existing acceptance tests
Make certain. This will be the content of the next version of this site.

QA Questions
• Correct content?
• Correct versions of content?
• Complete number of ﬁelds?
• Complete metadata? (urls, relations, dates,
authors, tags)
• Complete number of nodes?
• Images and media? (block live site)

Conclusion (?)
• traditional upgrade
• migrate
If you want something that is quick and your site's upgrade path supports it, go with a
traditional upgrade.
If you want to make a lot of structural changes and need ﬁne control over the upgrade path,
go with migrate.

Deployment
• Same issues as replacing any site, unless the
D6 site is incredibly simple.

Future of upgrades
• Upgrades are challenging
• Migrate is being added to Drupal 8 core, to
provide a smooth upgrade path from D6
and D7 core.
http://www.drupal4hu.com/node/381

Bookmarks
• http://drupalcode.org/project/drupal.git/
blob/refs/heads/7.x:/UPGRADE.txt
• https://drupal.org/project/drush_sup
• http://drupal.org/project/migrate
• http://drupal.org/project/migrate_d2d
• http://drupal.org/migrate
• http://drupal.org/project/coder (upgrade)
• http://drupal.org/project/hacked
• http://drupal.org/project/upgrade_status

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