backwards incompatible changes, or some of your patches conflict with
other changes, Wizard aims to make resolving these changes tractable.
-This document is divided into two sections: first, the basic procedure,
-and then troubleshooting tips for recalcitrant upgrades.
-
Summary
-------
git merge pristine --no-commit
# resolve conflicts
git commit -asm "$APPLICATION $VERSION-scripts"
- git tag $APP-$VERSION
.. note::
cd testdir_install_$APP_head
wizard prepare-config
-Manually restore any custom changes we may have made to the configuration
+With any luck, there will be no differences; if there are
+manually restore any custom changes we may have made to the configuration
file, make sure that no upstream changes broke our regular expressions
for matching. Then amend your commit and push back::
git commit --amend -a
git tag $APP-$VERSION-scripts
+ git push --force
git push --force --tags
On any other copies that have the older commit, run the following commands
commit. Be especially careful to make sure you don't nuke any in
configuration scripts changes.
+Implementation
+--------------
+
+If it is the first time you have pushed an upgrade for an application, you
+will have to write a few more methods in your :class:`wizard.app.Application`
+class: :meth:`~wizard.app.Application.upgrade`, :meth:`~wizard.app.Application.checkWeb`,
+:meth:`~wizard.app.Application.backup` and :meth:`~wizard.app.Application.restore`.
+The latter three may not seem so useful for just pushing an upgrade, but are helpful
+for integrity checking installations post-upgrade, and rolling back if something
+went wrong.
+
+:meth:`~wizard.app.Application.checkWeb` is a method that should check whether
+or not an application is running properly. We use this to prevent us from trying
+to upgrade an install that is not publically accessible, or was broken from
+the very start, and we use it to automatically determine if our upgrade was
+successful or not. A common and easy way to perform this check is to
+use the :meth:`~wizard.app.Application.checkWebPage` method, which, along
+with the parameters :meth:`~wizard.app.Application.checkWeb` accepts, accepts
+two more: ``page`` and ``output``, which correspond to the page to grab from
+the web and the output string to match for in this page,
+
+.. warning::
+
+ We still haven't quite figured out a good combination of in-depth error checking
+ and robustness against skin changes. This section should be further developed
+ with tips about this.
+
+:meth:`~wizard.app.Application.backup` and :meth:`~wizard.app.Application.restore`
+perform backup and restoration of non-filesystem contents; the most common application
+is for the database. :func:`wizard.app.backup_database` and :func:`wizard.app.restore_database`
+implement this common functionality, and for
+most application implementing these methods is as simple as:
+
+.. code-block:: python
+
+ def backup(self, deployment, backup_dir, options):
+ app.backup_database(backup_dir, deployment)
+ def restore(self, deployment, backup_dir, options):
+ app.restore_database(backup_dir, deployment)
+
+Finally, :meth:`~wizard.app.Application.upgrade` actually performs an upgrade,
+and will most frequently call a shell script or fetches a web page that will
+perform a schema upgrade.
+
+.. note::
+
+ When migrating an old-style autoinstall, it is neither expected nor
+ required for upgrade scripts for the intervening versions to be
+ created.
+
Troubleshooting
---------------
And then apply the patch. If the patch is complicated, you may get
warnings about hunks already being applied; you can ignore those warnings
(don't assume ``-R``!)
+
+Going retro
+-----------
+
+Under certain circumstances, you may need to splice in older versions
+of the application into your history. Do not rebase: you should never
+rebase published history. Instead, use the following procedure:
+
+Identify the version that, with regards to version numbering,
+directly precedes the version you'd like to add. For example, if
+you have the following commit tree:
+
+.. digraph:: original_dag
+
+ node [shape=square]
+ subgraph cluster_master {
+ bs -> as
+ as [label="1.0-scripts"]
+ bs [label="2.0-scripts"]
+ label = "master"
+ color = white
+ }
+ subgraph cluster_pristine {
+ b -> a
+ a [label="1.0"]
+ b [label="2.0"]
+ label = "pristine"
+ color = white
+ }
+ bs -> b
+ as -> a
+
+And you are adding the 1.1 version, 1.0 and 1.0-scripts are the
+tags immediately preceding this version. Create temporary
+branches (we'll name them ``tmaster`` and ``tpristine``) pointing
+to these tags::
+
+ git checkout -b tmaster
+ git reset --hard 1.0-scripts
+ git checkout -b tpristine
+ git reset --hard 1.0
+
+Find the committer date associated with the ``tmaster`` commit using ``git show tmaster``
+and note it somewhere::
+
+ DATE=`git show tmaster --pretty="format:%cd" | head -n1`
+
+Next, begin performing ordinary procedure for preparing the
+pristine copy. There are two caveats: you will need to use ``--force``
+to make ``wizard prepare-pristine`` not complain about not being on
+the ``pristine`` branch, and you will need to falsify the author
+and committer time on the commits to be the times we noted down
+previously::
+
+ # on the tpristine branch
+ wizard prepare-pristine $APP-$VERSION --force
+ env GIT_AUTHOR_DATE="$DATE" GIT_COMMITTER_DATE="$DATE" git commit -asm "$APPLICATION $VERSION"
+ git tag $APP-$VERSION
+
+.. note::
+
+ The date falsification is necessary to make Git prefer the
+ later version tag when a commit has this (newer) commit and
+ the most up-to-date version as merge parents. By default
+ Git prefers the temporally closest commit.
+
+Next, merge the changes to the scriptsified ``tmaster`` (not ``master``!) copy,
+and falsify the dates as well::
+
+ git checkout tmaster
+ git merge tpristine --no-commit
+ # resolve conflicts
+ env GIT_AUTHOR_DATE="$DATE" GIT_COMMITTER_DATE="$DATE" git commit -asm "$APPLICATION $VERSION-scripts"
+ git tag $APP-$VERSION-scripts
+
+Note that we are creating a tag, because otherwise there is not an easy way
+to refer to this non-HEAD tag. On a scripts server with Wizard pointed at the
+latest version, run::
+
+ cd tests
+ env WIZARD_NO_COMMIT=1 ./$APP-install-test.sh $VERSION
+ cd testdir_install_$APP_$VERSION
+ wizard prepare-config
+
+Note that ``$VERSION`` is specified explicitly. If there are changes,
+manually restore any custom changes we may have made, then amend your commit and
+push back::
+
+ # you probably lost your environment variable
+ DATE=`git show HEAD --pretty="format:%ad" | head -n1`
+ env GIT_AUTHOR_DATE="$DATE" GIT_COMMITTER_DATE="$DATE" git commit --amend -a
+ git tag -d $APP-$VERSION-scripts
+ git tag $APP-$VERSION-scripts
+ git push --force --tags
+
+And on your now invalid version, grab the new version::
+
+ git fetch --tags --force $REMOTE
+
+Note that there is no need to reset the master branch, which hasn't changed.
scripts.mit.edu / wizard.git / blobdiff