Updating Diffs

The admin training was recently converted completely to use diffs. This was done so we could build a git repository, and time travel to any point within admin training, in support of students and testing.

Here’s some common editing scenarios to help you out.

Agenda

In this tutorial, we will:

1. Updating Diffs
   1. How it Works
   2. Automation
2. Git-Gat Knick-Knacks: Some Common Scenarios
   1. I want to update the text of a specific commit
   2. Upgrading an existing tutorial
   3. I want to add a new commit
3. Errors that can occur and how to fix them
   1. sha1 information is lacking or useless

How it Works

Tutorials are written with diffs that look like this:

```diff
--- /dev/null
+++ b/ansible.cfg
@@ -0,0 +1,4 @@
+[defaults]
+interpreter_python = /usr/bin/python3
+inventory = hosts
+retry_files_enabled = false
```
{: data-commit="Add ansible.cfg"}

The data-commit will be turned into the commit message, so, you can write something nice here. Otherwise it’s a pretty standard diff. For tutorials which are written in this way, we can extract all of the diffs.

Frogging

In knitting you sometimes need to rip out the stitches, a process sometimes called frogging.

If they are not secured, the loops of a knitted course will come undone when their yarn is pulled; this is known as ripping out, unravelling knitting, or humorously, frogging (because you ‘rip it’, this sounds like a frog croaking: ‘rib-bit’). via Wikipedia

$ python bin/knit-frog.py topics/admin/tutorials/singularity/tutorial.md /tmp/03-singularity
/tmp/03-singularity-commit-0000-add-golang-and-singulary-ansible-roles.patch
/tmp/03-singularity-commit-0001-configure-golang-and-singularity.patch
/tmp/03-singularity-commit-0002-add-the-roles-to-the-playbook.patch
/tmp/03-singularity-commit-0003-configure-the-container-and-dependency-resolvers.patch
/tmp/03-singularity-commit-0004-configure-the-dependency-resolvers.patch
/tmp/03-singularity-commit-0005-configure-the-container-resolver.patch
/tmp/03-singularity-commit-0006-update-the-job-conf-xml-with-singularity-destination.patch

This rips out the diffs and writes them into patch files.

Knitting

With a series of patch files, we have a similar script to knit them back together.

$ python bin/knit.py topics/admin/tutorials/singularity/tutorial.md --patches /tmp/03-singularity*

This takes the patch files and lines them up in the tutorial. It is not intelligent. You should have the same number of patch files as you do diffs with data-commit. Up to you to manage that.

Automation

But mostly you don’t need to care about the knit.py or knit-frog.py, we have knit-automated.sh which takes care of calling those properly. You can call it with export to write the patches into /tmp/git-gat/

$ ./bin/knit-automated.sh export
/tmp/git-gat/0-ansible-galaxy-commit-0000-add-requirements.patch
/tmp/git-gat/0-ansible-galaxy-commit-0001-add-ansible-cfg.patch
/tmp/git-gat/0-ansible-galaxy-commit-0002-add-hosts.patch
/tmp/git-gat/0-ansible-galaxy-commit-0003-add-initial-group-variables-file.patch
/tmp/git-gat/0-ansible-galaxy-commit-0004-add-initial-galaxy-playbook.patch
/tmp/git-gat/0-ansible-galaxy-commit-0005-add-pip--miniconda--galaxy-to-playbook.patch
/tmp/git-gat/0-ansible-galaxy-commit-0006-configure-miniconda-and-galaxy.patch
[...]
/tmp/git-gat/6-pulsar-commit-0000-add-requirements.patch
/tmp/git-gat/6-pulsar-commit-0001-configure-rabbitmq.patch
/tmp/git-gat/6-pulsar-commit-0002-add-role.patch
/tmp/git-gat/6-pulsar-commit-0003-add-pulsar-group-variables.patch
/tmp/git-gat/6-pulsar-commit-0004-add-pulsar-host.patch
/tmp/git-gat/6-pulsar-commit-0005-add-pulsar-playbook.patch
/tmp/git-gat/6-pulsar-commit-0006-add-pulsar-plugin.patch
/tmp/git-gat/6-pulsar-commit-0007-add-pulsar-destination.patch
/tmp/git-gat/6-pulsar-commit-0008-send-bwa-and-bwa-mem-to-pulsar.patch

And there you can build a repository from them!

[hxr@mk:/tmp/git-gat]$ git init
[hxr@mk:/tmp/git-gat]$ git am -3 *
Applying: admin/ansible-galaxy/0000: Add requirements
applying to an empty history
Applying: admin/ansible-galaxy/0001: Add ansible.cfg
Applying: admin/ansible-galaxy/0002: Add hosts
Applying: admin/ansible-galaxy/0003: Add initial group variables file
Applying: admin/ansible-galaxy/0004: Add initial galaxy playbook
Applying: admin/ansible-galaxy/0005: Add pip, miniconda, galaxy to playbook
[...]
Applying: admin/pulsar/0004: Add pulsar host
Applying: admin/pulsar/0005: Add pulsar playbook
Applying: admin/pulsar/0006: Add pulsar plugin
Applying: admin/pulsar/0007: Add pulsar destination
Applying: admin/pulsar/0008: Send bwa and bwa-mem to pulsar

Et voila!

$ rm *.patch
$ tree
.
├── ansible.cfg
├── files
│   └── galaxy
│       ├── config
│       │   ├── dependency_resolvers_conf.xml
│       │   └── tool_destinations.yml
│       ├── dynamic_job_rules
│       │   ├── map_resources.py
│       │   └── my_rules.py
│       └── tools
│           └── testing.xml
├── galaxy.yml
├── group_vars
│   ├── all.yml
│   ├── galaxyservers.yml
│   └── pulsarservers.yml
├── hosts
├── pulsar.yml
├── requirements.yml
└── templates
    ├── galaxy
    │   └── config
    │       ├── container_resolvers_conf.xml.j2
    │       ├── job_conf.xml.j2
    │       └── job_resource_params_conf.xml.j2
    └── nginx
        ├── galaxy.j2
        └── redirect-ssl.j2

10 directories, 18 files

When you’re done editing, you can run the ./bin/knit-automated.sh import, it will

• extract the history as patches (using git format-patch)
• knit them into the tutorials

Warning: Danger: Don't mess with the commit names at this step

They’re used for figuring out which commit a patch file belongs to. Sorry!

Git-Gat Knick-Knacks: Some Common Scenarios

I want to update the text of a specific commit

Question: Example problem

I want to edit the commit titled “Add production facing vars” to add an addtional variable in admin/ansible-galaxy.

Hands-on: Make the change you want to see in the GAT

1. Start by exporting

   $ bash bin/knit-automated.sh export
   

2. Build the repository, and apply the patches to get the current state.

   [hxr@mk:/tmp/git-gat]$ git init
   [hxr@mk:/tmp/git-gat]$ git am -3 *.patch
   Applying: admin/ansible-galaxy/0000: Add requirements
   applying to an empty history
   Applying: admin/ansible-galaxy/0001: Add ansible.cfg
   Applying: admin/ansible-galaxy/0002: Add hosts
   Applying: admin/ansible-galaxy/0003: Add initial group variables file
   Applying: admin/ansible-galaxy/0004: Add initial galaxy playbook
   Applying: admin/ansible-galaxy/0005: Add pip, miniconda, galaxy to playbook
   Applying: admin/ansible-galaxy/0006: Configure miniconda and galaxy
   Applying: admin/ansible-galaxy/0007: Configure galaxy config
   [...]
   [hxr@mk:/tmp/git-gat]$ rm *.patch
   

3. Find the commit:

   $ git log --oneline | grep "Add production facing vars"
   2f5b416 admin/ansible-galaxy/0022: Add production facing vars
   

4. Edit rebase one upstream of that commit

   $ git rebase -i 2f5b416~
   

   Mark it for editing

   edit 2f5b416 admin/ansible-galaxy/0022: Add production facing vars
   pick a352bec admin/ansible-galaxy/0023: Add nginx x-accel-redir and g-i-g webhook config to nginx
   pick 59f9ff0 admin/singularity/0000: Add golang and singulary ansible roles
   pick f38ddbf admin/singularity/0001: Configure golang and singularity
   

   It should stop there

   Stopped at 2f5b416...  admin/ansible-galaxy/0022: Add production facing vars
   You can amend the commit now, with
   
     git commit --amend
   
   Once you are satisfied with your changes, run
   
     git rebase --continue
   

5. Open your file, make your change. Here I’m showing the change I made with git diff

   $ git diff | cat
   diff --git a/group_vars/galaxyservers.yml b/group_vars/galaxyservers.yml
   index 15fbf1e..8fe4343 100644
   --- a/group_vars/galaxyservers.yml
   +++ b/group_vars/galaxyservers.yml
   @@ -53,6 +53,8 @@ galaxy_config:
        expose_user_name: true
        expose_dataset_path: true
        expose_potentially_sensitive_job_metrics: true
   +    # NFS workarounds
   +    retry_job_output_collection: 3
        # Debugging
        cleanup_job: onsuccess
        allow_user_impersonation: true
   

6. The status probably looks like this, the file that was changed in that commit is marked as modified

   $ git status
   interactive rebase in progress; onto 7284036
   Last command done (1 command done):
      edit 2f5b416 admin/ansible-galaxy/0022: Add production facing vars
   Next commands to do (46 remaining commands):
      pick 3c6a72e admin/ansible-galaxy/0023: Add nginx x-accel-redir and g-i-g webhook config to nginx
      pick a893955 admin/singularity/0000: Add golang and singulary ansible roles
     (use "git rebase --edit-todo" to view and edit)
   You are currently editing a commit while rebasing branch 'main' on '7284036'.
     (use "git commit --amend" to amend the current commit)
     (use "git rebase --continue" once you are satisfied with your changes)
   
   Changes to be committed:
     (use "git restore --staged <file>..." to unstage)
           modified:   group_vars/galaxyservers.yml
   

7. Ammend the commit, and continue the rebase

   $ git commit --amend
   [detached HEAD ed290de] admin/ansible-galaxy/0022: Add production facing vars
    Author: The Galaxy Training Network <galaxytrainingnetwork@gmail.com>
    Date: Mon Feb 15 14:06:56 2021 +0100
    1 file changed, 22 insertions(+)
   $ git rebase --continue
   Successfully rebased and updated refs/heads/main.
   

8. Import the changes back in the GTN repository

   ./bin/knit-automated.sh import
   

The above shows commands with outputs, the rest will be more abbreviated

Upgrading an existing tutorial

Question: Example problem

I have a new tutorial in the schedule and I want to upgrade it to use this feature

Hands-on: Make the change you want to see in the GAT

1. Start by exporting

   $ bash bin/knit-automated.sh export
   

2. Build the repository… up to the point where your tuto is

   [hxr@mk:/tmp/git-gat]$ git init
   [hxr@mk:/tmp/git-gat]$ git am -3 0* 1* 2*
   Applying: admin/ansible-galaxy/0000: Add requirements
   applying to an empty history
   Applying: admin/ansible-galaxy/0001: Add ansible.cfg
   Applying: admin/ansible-galaxy/0002: Add hosts
   Applying: admin/ansible-galaxy/0003: Add initial group variables file
   Applying: admin/ansible-galaxy/0004: Add initial galaxy playbook
   Applying: admin/ansible-galaxy/0005: Add pip, miniconda, galaxy to playbook
   Applying: admin/ansible-galaxy/0006: Configure miniconda and galaxy
   Applying: admin/ansible-galaxy/0007: Configure galaxy config
   [...]
   

3. Go diff-by-diff in your tutorial, making the change, and then making a new commit on top for each diff. For each of these, add the {: data-commit="Something usful"} below the commit.

   Do they have a { % endraw % }? then move that above the backticks.

4. Format them as patches

   git format-patch <the last commit before you started committing>
   

5. Knit them together

   python bin/knit.py topics/admin/tutorials/<yourtuto>/tutorial.md --patches /tmp/<the-patches-you-exported>*
   

6. That’s part one done! Now we need to finish the rest of the patches.

7. Update ./bin/knit-automated.sh to include your tutorial in the right order.

8. Go through an export-import cycle

   $ rm -rf /tmp/git-gat/
   $ ./bin/knit-automated.sh export
   $ cd /tmp/git-gat/
   $ git am -3 *.patch # Resolve any conflicts
   $ cd -
   $ ./bin/knit-automated.sh import
   

9. Done!

I want to add a new commit

Hands-on: Make the change you want to see in the GAT

1. Add your commit where it belongs in the tutorial

      
   { raw }
   ```diff
   --- a/requirements.yml
   +++ b/requirements.yml
   @@ -22,3 +22,7 @@
      version: 0.0.2
    - src: galaxyproject.slurm
      version: 0.1.3
   +- name: usegalaxy_eu.rabbitmq
   +  version: 0.1.0
   +- src: galaxyproject.pulsar
   +  version: 1.0.7
   { endraw }
   ```
   {: data-commit="Add requirements"}
      
   

   Use your imagination to pretend the raw/endraw tags are correct with the missing percent signs.

2. Now in the above diff we’ve written some — and +++ and more metadata we don’t really have. So: just make it up, the commit will fail to apply, and we’ll go fix it. You can really write anything here you want, and the diff will fail which is what we want.

3. Now, go apply the commits

   $ ./bin/knit-automated.sh export
   $ cd /tmp/git-gat/
   $ git am -3 *.patch # Resolve any conflicts
   

4. This will fail. Here’s how to fix it:

   1. Run git am --show-current-patch to see the above diff you’ve inserted (or the otherwise incorrect diff that’s a downstream result of your new change).
   2. Make the correct change to the file on disk.
   3. git add <path>
   4. git am --continue

5. You’ll probably have to do this quite a few more times, diffs have a habit of affecting downstream diffs (e.g. changing a version number or being included in the diff context.)

6. Once you’ve finished all of them, you’ll just ./bin/knit-automated.sh import and commit the resulting changes!

The alternative to the above approach is

1. Export
2. git rebase and make the corresponding change in the history
3. Let the rebase finish
4. Insert a ‘dummy’ diff (raw/open code+diff/endraw/close code/data-commit tag) without any content and then run import which should insert it in the correct place.

Errors that can occur and how to fix them

sha1 information is lacking or useless

This is because there’s a mismatch in the commits you’re trying to apply and what the merge commit is seeing. Usually you won’t notice. fix by rebasing, and roundtripping the commits.

Applying: admin/pulsar/0012: Send bwa and bwa-mem to pulsar
Tagging step-17
Committing 18-gxadmin-commit-0000-add-requirement.patch
18-gxadmin-commit-0002-add-the-gxadmin-role.patch
Applying: admin/gxadmin/0000: Add requirement
error: sha1 information is lacking or useless (requirements.yml).
error: could not build fake ancestor
Patch failed at 0001 admin/gxadmin/0000: Add requirement
hint: Use 'git am --show-current-patch' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".

Here you grumble at how picky it is.

$ git am --show-current-patch
From: The Galaxy Training Network <galaxytrainingnetwork@gmail.com>
Date: Mon, 15 Feb 2021 14:06:56 +0100
Subject: admin/gxadmin/0000: Add requirement


--- a/requirements.yml
+++ b/requirements.yml
@@ -26,3 +26,5 @@
   version: 0.1.0
 - src: galaxyproject.pulsar
   version: 1.0.6
+- src: galaxyproject.gxadmin
+  version: 0.0.8
--
2.25.1

That looks right, doesn’t it? But if we grep we’ll see

$ ag -Q '1.0.6' topics/admin
topics/admin/tutorials/gxadmin/tutorial.md
55:>       version: 1.0.6

topics/admin/tutorials/monitoring/tutorial.md
80:>       version: 1.0.6

topics/admin/tutorials/pulsar/tutorial.md
149:>    +  version: 1.0.6

again right, but is it? No. Github is testing the merge commit. Rebase your commits, and now you’ll see:

$ ag -Q '1.0.6' topics/admin
topics/admin/tutorials/gxadmin/tutorial.md
55:>       version: 1.0.6

topics/admin/tutorials/monitoring/tutorial.md
80:>       version: 1.0.6

$ ag -Q '1.0.7' topics/admin
topics/admin/tutorials/pulsar/tutorial.md
149:>    +  version: 1.0.7

Aha, two different version. This is what breaks the hashes (hence the error message.)

Roundtripping the commits and fixing up everywhere there was a single character difference in the diff context (UGH) will fix it.

Key points

• The knitting script works OK?

• Learn to rebase now, if you haven’t yet

• git am is not fun

• If you have issues, ping me.

Frequently Asked Questions

Feedback

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Citing this Tutorial

1. Helena Rasche, 2022 Updating diffs in admin training (Galaxy Training Materials). https://training.galaxyproject.org/training-material/topics/contributing/tutorials/admin-knitting/tutorial.html Online; accessed TODAY
2. Batut et al., 2018 Community-Driven Data Analysis Training for Biology Cell Systems 10.1016/j.cels.2018.05.012

BibTeX

@misc{contributing-admin-knitting,
author = "Helena Rasche",
title = "Updating diffs in admin training (Galaxy Training Materials)",
year = "2022",
month = "10",
day = "18"
url = "\url{https://training.galaxyproject.org/training-material/topics/contributing/tutorials/admin-knitting/tutorial.html}",
note = "[Online; accessed TODAY]"
}
@article{Batut_2018,
    doi = {10.1016/j.cels.2018.05.012},
    url = {https://doi.org/10.1016%2Fj.cels.2018.05.012},
    year = 2018,
    month = {jun},
    publisher = {Elsevier {BV}},
    volume = {6},
    number = {6},
    pages = {752--758.e1},
    author = {B{\'{e}}r{\'{e}}nice Batut and Saskia Hiltemann and Andrea Bagnacani and Dannon Baker and Vivek Bhardwaj and Clemens Blank and Anthony Bretaudeau and Loraine Brillet-Gu{\'{e}}guen and Martin {\v{C}}ech and John Chilton and Dave Clements and Olivia Doppelt-Azeroual and Anika Erxleben and Mallory Ann Freeberg and Simon Gladman and Youri Hoogstrate and Hans-Rudolf Hotz and Torsten Houwaart and Pratik Jagtap and Delphine Larivi{\`{e}}re and Gildas Le Corguill{\'{e}} and Thomas Manke and Fabien Mareuil and Fidel Ram{\'{\i}}rez and Devon Ryan and Florian Christoph Sigloch and Nicola Soranzo and Joachim Wolff and Pavankumar Videm and Markus Wolfien and Aisanjiang Wubuli and Dilmurat Yusuf and James Taylor and Rolf Backofen and Anton Nekrutenko and Björn Grüning},
    title = {Community-Driven Data Analysis Training for Biology},
    journal = {Cell Systems}
}
                   

Developing GTN training material

This tutorial is part of a series to develop GTN training material, feel free to also look at:

1. Overview of the Galaxy Training Material
2. Adding auto-generated video to your slides
3. Adding Quizzes to your Tutorial
4. Contributing with GitHub via command-line
5. Contributing with GitHub via its interface
6. Creating a new tutorial
7. Creating content in Markdown
8. Creating Interactive Galaxy Tours
9. Creating Slides
10. Design and plan session, course, materials
11. Generating PDF artefacts of the website
12. GTN Metadata
13. Including a new topic
14. Principles of learning and how they apply to training and teaching
15. Running the GTN website locally
16. Running the GTN website online using GitPod
17. Teaching Python
18. Tools, Data, and Workflows for tutorials
19. Updating diffs in admin training