# Seeking recommendations for flow reuse

**URL:** <https://cylc.discourse.group/t/seeking-recommendations-for-flow-reuse/951>\
**Category:** Cylc Support\
**Created:** [May 9, 2024, 1:47pm UTC](https://cylc.discourse.group/t/seeking-recommendations-for-flow-reuse/951 "2024-05-09T13:47:54Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![aulemahal](https://yyz2.discourse-cdn.com/free1/user_avatar/cylc.discourse.group/aulemahal/32/341_2.png) [@aulemahal](https://cylc.discourse.group/u/aulemahal)\
**Post date:** [May 9, 2024, 1:47pm UTC](https://cylc.discourse.group/t/seeking-recommendations-for-flow-reuse/951/1 "2024-05-09T13:47:54Z")

</div>

Hi all,

I am using the latest cylc with the rose-suite.conf option. Currently my setup looks like this:

```auto
git-versioned-folder/
    workflow_template/
        [...]
        rose-suite.conf.template
workflow-folder/
    workflow-instance1/
        [...] 
        rose-suite.conf    
    workflow-instance2/
        [...] 
        rose-suite.conf    

```

In short, my workflow is developed in a git repo. When I want to run an instance of said workflow, I copy the whole folder to somewhere else, I edit the rose-suite.conf file and then I install the workflow.

While it seems safe to have each instances in independent folders, it becomes a hassle when I need to make some tweaks to an instance and than import those change back into the template. At this point, only the `rose-suite.conf` file contains information that changes from instance to instance.

To avoid the duplication of folders, I would like to be able to do something like:

```auto
cylc install -n wf-name --conf wf-instances/instance1.conf ~/git-versioned-folder/workflow_template/

```

So, having only one folder for workflow development, but being able to change the name/location of the `rose-suite.conf` in the install call. So my multiple workflow instances would all be installed from the same folder, except for the configuration itself.

I don’t think this is possible. Would it be an interesting addition ?

How do people manage this kind of usage ? I read a bit about rose itself and it looks like it could address this issue, but it also seems much larger in scope, adding a lot more configurations and moving parts that I don’t think I need ?

---

<div class="post-metadata">

**Author:** ![wxtim](https://yyz2.discourse-cdn.com/free1/user_avatar/cylc.discourse.group/wxtim/32/151_2.png) [@wxtim](https://cylc.discourse.group/u/wxtim)\
**Post date:** [May 9, 2024, 3:07pm UTC](https://cylc.discourse.group/t/seeking-recommendations-for-flow-reuse/951/2 "2024-05-09T15:07:55Z")

</div>

Once you have used `cylc install` you can edit your source without causing any changes to the running workflow. That is why we have `cylc install`.

This means that you could use Git to make these copies:

```auto
git checkout -b "my_branch"
# Make changes
cylc vip --run-name "$(git br --show-current)"

```

It’s worth pointing out too, that if you were to `cylc install` without making a commit, the diff is recorded in `cat ~/cylc-run/<workflow>/log/version/uncommitted.diff`and the commit has is stored in `~/cylc-run/<workflow>/log/version/vcs.json `.

A second way of doing something similar is using rose-suite optional configs:

```auto
mkdir opt
cat > opt/rose-suite-myoption.conf << __HERE__
[env]
myvar="This value will override myvar from rose-suite.conf"
__HERE__

cylc vip -O myoption --run-name "whatever-you-want-to-call-it"

```

---

<div class="post-metadata">

**Author:** ![aulemahal](https://yyz2.discourse-cdn.com/free1/user_avatar/cylc.discourse.group/aulemahal/32/341_2.png) [@aulemahal](https://cylc.discourse.group/u/aulemahal)\
**Post date:** [May 9, 2024, 4:23pm UTC](https://cylc.discourse.group/t/seeking-recommendations-for-flow-reuse/951/3 "2024-05-09T16:23:38Z")

</div>

Nice! Thanks for the quick answer, I knew there were ways I didn’t know about.

I’ll look into both options. In my use case, I often have multiple instances of the same workflow running at the same time and I currently didn’t think useful to have the instance’s `rose-suite.conf` committed in the repo. The second option really looks like what I was imagining.

---

<div class="post-metadata">

**Author:** ![wxtim](https://yyz2.discourse-cdn.com/free1/user_avatar/cylc.discourse.group/wxtim/32/151_2.png) [@wxtim](https://cylc.discourse.group/u/wxtim)\
**Post date:** [May 10, 2024, 8:33am UTC](https://cylc.discourse.group/t/seeking-recommendations-for-flow-reuse/951/4 "2024-05-10T08:33:18Z")

</div>

Just to be more explicit - your copying the source file to a new location duplicates the functioning of `cylc install`, which is mostly just rsyncing your source file to a new file in `~/cylc-run`.

```bash
cd myworkflow
cylc install ~/cylc-src/myworkflow # Will install # ~/cylc-run/myworkflow/run1
sed -i 's@x=42@x=84@g' rose-suite.conf
cylc install ~/cylc-install/myworkflow # Will install # ~/cylc-run/myworkflow/run2

```

When you use `cylc play` it is only interested in the specific copy in the `cylc-run` directory, and not in the other copies or the source directory. This means that installing gives you a snapshot of the source directory at the time you install.

If in one of the tasks you were to have `script = echo {{x}}` then that task in run1 will always return 42, and in run2 will always be 84.