Yeah. TP - I like that explicit separation. It's much cleaner. I still have to think about the name though. While I see where ExternalPythonOperator comes from, It sounds a bit less than obvious. I think the name should somehow contain "Environment" because very few people realise that running Python from a virtualenv actually implicitly "activates" the venv. I think maybe deprecating the old PythonVirtualenvOperator and introducing two new operators: PythonInCreatedVirtualEnvOperator, PythonInExistingVirtualEnvOperator ? Not exactly those names - they are too long - but something like that. Maybe we should get rid of Python in the name at all ?
BTW. I think we should generally do more of the discussions here and express our thoughts about Airflow here. Even if there are no answers or interest immediately, I think that it makes sense to do a bit of a melting pot that sometimes might produce some cool (or rather hot) stuff as a result. On Wed, Aug 17, 2022 at 8:45 AM Tzu-ping Chung <t...@astronomer.io.invalid> wrote: > > One thing I thought of (but never bothered to write about) is to introduce a > separate operator instead, say ExternalPythonOperator (bike shedding on name > is welcomed), that explicitly takes a path to the interpreter (say in a > virtual environment) and just use that to run the code. This also enables > users to create a virtual environment upfront, but avoids needing to overload > PythonVirtualenvOperator for the purpose. This also opens an extra use case > that you can use any Python installation to run the code (say a > custom-compiled interpreter), although nobody asked about that. > > TP > > > On 13 Aug 2022, at 02:52, Jeambrun Pierre <pierrejb...@gmail.com> wrote: > > I feel like this is a great alternative at the price of a very moderate > effort. (I'd be glad to help with it). > > Mutually exclusive sounds good to me as well. > > Best, > Pierre > > Le ven. 12 août 2022 à 15:23, Jarek Potiuk <ja...@potiuk.com> a écrit : >> >> Mutually exclusive. I think that has the nice property of forcing people to >> prepare immutable venvs upfront. >> >> On Fri, Aug 12, 2022 at 3:15 PM Ash Berlin-Taylor <a...@apache.org> wrote: >>> >>> Yes, this has been on my background idea list for an age -- I'd love to see >>> it happen! >>> >>> Have you thought about how it would behave when you specify an existing >>> virtualenv and include requirements in the operator that are not already >>> installed there? Or would they be mutually exclusive? (I don't mind either >>> way, just wondering which way you are heading) >>> >>> -ash >>> >>> On Fri, Aug 12 2022 at 14:58:44 +02:00:00, Jarek Potiuk <ja...@potiuk.com> >>> wrote: >>> >>> Hello everyone, >>> >>> TL;DR; I propose to extend our PythonVirtualenvOperator with "use existing >>> venv" feature and make it a viable way of handling some multi-dependency >>> sets using multiple pre-installed venvs. >>> >>> More context: >>> >>> I had this idea coming after a discussion in our Slack: >>> https://apache-airflow.slack.com/archives/CCV3FV9KL/p1660233834355179 >>> >>> My thoughts were - why don't we add support for "use existing venv" in >>> PythonVirtualenvOperator as first-class-citizen ? >>> >>> Currently (unless there are some tricks I am not aware of) or extend PVO, >>> the PVO will always attempt to create a virtualenv based on extra >>> requirements. And while it gives the users a possibility of having some >>> tasks use different dependencies, the drawback is that the venv is created >>> dynamically when tasks starts - potentially a lot of overhead for startup >>> time and some unpleasant failure scenarios - like networking problems, PyPI >>> or local repoi not available, automated (and unnoticed) upgrade of >>> dependencies. >>> >>> Those are basically the same problems that caused us to strongly discourage >>> our users in our Helm Chart to use _PIP_ADDITIONAL_DEPENDENCIES in >>> production and criticize the Community Helm Chart for dynamic dependency >>> installation they promote as a "valid" approach. Yet our PVO currently does >>> exactly this. >>> >>> We had some past discussions how this can be improved - with caching, or >>> using different images for different dependencies and similar - and even we >>> have >>> https://cwiki.apache.org/confluence/display/AIRFLOW/AIP-46+Runtime+isolation+for+airflow+tasks+and+dag+parsing >>> proposal to use different images for different sets of requirements. >>> >>> Proposal: >>> >>> During the discussion yesterday I started to think a simpler solution is >>> possible and rather simple to implement by us and for users to use. >>> >>> Why not have different venvs preinstalled and let the PVO choose the one >>> that should be used? >>> >>> It does not invalidate AIP-46. AIP-46 serves a bit different purpose and >>> some cases cannot be handled this way - when you need different "system >>> level" dependencies for example) but it might be much simpler from >>> deployment point of view and allow it to handle "multi-dependency sets" for >>> Python libraries only with minimal deployment overhead (which AIP-46 >>> necessarily has). And I think it will be enough for a vast number of the >>> "multi-dependency-sets" cases. >>> >>> Why don't we allow the users to prepare those venvs upfront and simply >>> enable PVE to use them rather than create them dynamically ? >>> >>> Advantages: >>> >>> * it nicely handles cases where some of your tasks need a different set of >>> dependencies than others (for execution, not necessarily parsing at least >>> initially). >>> >>> * no startup time overhead needed as with current PVO >>> >>> * possible to run in both cases - "venv installation" and "docker image" >>> installation >>> >>> * it has finer granularity level than AIP-46 - unlike in AIP-46 you could >>> use different sets of dependencies >>> >>> * very easy to pull off for the users without modifying their >>> deployments,For local venv, you just create the venvs, For Docker image >>> case, your custom image needs to add several lines similar to: >>> >>> RUN python -m venv --system-site-packages PACKAGE1==NN PACKAGE2==NN >>> /opt/venv1 >>> RUN python -m venv --system-site-packages PACKAGE1==NN PACKAGE2==NN >>> /opt/venv2 >>> >>> and PythonVenvOperator should have extra "use_existing_venv=/opt/venv2") >>> parameter >>> >>> * we only need to manage ONE image (!) even if you have multiple sets of >>> dependencies (this has the advantage that it is actually LOWER overhead >>> than having separate images for each env -when it comes to various >>> resources overhead (same workers could handle multiple dependency sets for >>> examples, same image is reused by multiple PODs in K8S etc. ). >>> >>> * later (when AIP-43 (separate dag processor with ability to use different >>> processors for different subdirectories) is completed and AIP-46 is >>> approved/implemented, we could also extend DAG Parsing to be able to use >>> those predefined venvs for parsing. That would eliminate the need for local >>> imports and add support to even use different sets of libraries in >>> top-level code (per DAG, not per task). It would not solve different >>> "system" level dependencies - and for that AiP-46 is still a very valid >>> case. >>> >>> Disadvantages: >>> >>> I thought very hard about this one and I actually could not find any >>> disadvantages :) >>> >>> It's simple to implement, use and explain, it can be implemented very >>> quickly (like - in a few hours with tests and documentation I think) and >>> performance-wise it is better for any other solution (including AIP-46) >>> providing that the case is limited to different Python dependencies. >>> >>> But possibly there are things that I missed. It all looks too good to be >>> true, and I wonder why we do not have it already today - once I thought >>> about it, it seems very obvious. So I probably missed something. >>> >>> WDYT? >>> >>> J. >>> >>> >>> >>> >>> >>> >>> >
