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<@ULVA73B9P> we have an automation that has a trig...
# ask-marvin
y
@Marvin we have an automation that has a trigger, which should be triggered when the flow run into "completed" status. However, it wasn't triggered after the flow went to "completed" status. Could you please help with that?
Copy code
CompoundTrigger(
        
        triggers=[
                    EventTrigger(
                        type = "event",
                        event_type="prefect.flow_run.state.changed",
                        match={
                            "state": "completed",
                            "deployment_id": "********"
                        },
                        threshold = 1,
                        posture = "Proactive",
                        within = 1
                    )
                ],
                require=1  # Trigger only once
    )
m
I see you're using an 
EventTrigger
nested within a 
CompoundTrigger
, set to fire when a flow run changes to "completed" status. It seems like you're using the Prefect 3.x version. A critical detail here is that proactive triggers, by which you seem to be operating since their 
posture
is set to "Proactive", require a 
within
value of at least 10 seconds, but you have it set to 1. This might not be sufficient for the system to detect the status change. Therefore, try initializing it with a value of, say, 10 or greater. Additionally, there's the choice between reactive and proactive triggers you should be conscious of. Proactive triggers like yours fire when their threshold has not been met by the end of the time window, that is defined by the 
within
parameter. Here's an explanation on custom event triggers, including points on proactive and reactive postures that should help refine your understanding and setup. And just remember, sometimes these automations can be like me on a Monday morning—sluggish to react! But with these tweaks, you should hopefully see quicker responses.
It looks like you are using a trigger mechanism in Python, probably implemented for automating some actions when a Prefect flow changes state to "completed." However, for better assistance, I need to know your Prefect version to guide you properly, as the underlying mechanism for triggers might vary between versions 2.x and 3.x. Without inferring or confirming your exact version, I'll proceed by researching both Prefect 2.x and 3.x documentation to provide you with potential insights into resolving the issue. Please hold on a moment. It appears I made an error by not providing search queries for the documentation search. Let me search again using specific queries related to your issue with the flow run state trigger. Please hang tight while I sort this out! Based on my research, there are ways to handle state changes and automate triggers in Prefect both for versions 2.x and 3.x. However, the setup you mentioned might be slightly off if you're not seeing the trigger action after a flow run completes. Here are some pointers that might help you: 1. Prefect 2.x: - State Change Hooks: These allow you to execute certain functions in response to state changes. If you're trying to trigger automation, ensure your hooks are properly configured. - Also, check the automation concepts page for more insights on setting up triggers with correct matching criteria. 2. Prefect 3.x: - Manage States: Explore the on_completion or similar hooks that may be useful to your scenario. - Automation Triggers: Ensure that your trigger events are correctly configured. The event type should be precisely matched to 
prefect.flow_run.state.changed
, and you may explore using different fields like 
expect
to handle triggers correctly. General Things to Check: - Ensure that the 
"state": "completed"
you are checking in the match dictionary is correctly spelled and aligned with what your Prefect configuration expects. - Verify the event grammar and resource matching aspects as discussed in Prefect 3.x to see if they apply to your version. Every now and then, technology has its own ways of keeping us entertained with small quirks! If you need precise debugging based on your Prefect version, you might want to explore their respective documentation to troubleshoot further. Let me know if you need help with more specific adjustments!
y
sorry I was using "Reactive" but it didn't work either
Copy code
trigger = CompoundTrigger(
        
        triggers=[
                    EventTrigger(
                        type = "event",
                        event_type="prefect.flow_run.state.changed",
                        match={
                            "state": "completed",
                            "deployment_id": "535c5770-c63f-4d88-b4dd-5b7aff0ee8df"
                        },
                        threshold = 1,
                        posture = "Reactive",
                        within = 1
                    )
                ],
                require="any"  # Trigger only once
    )
we're using prefect 2.x
@Marvin I'm updating my trigger, so that when the flow went to the completed status, and the flow run has a specific job variable, the action can be triggered. Is it possible to set up a trigger like that?
m
Yes, you can set up a trigger that checks for specific conditions, such as the flow reaching a "completed" state and having a particular job variable. This would involve extending your trigger logic to include additional criteria based on the flow run's metadata or parameters. Here's a general approach for how you might achieve this: 1. Event Matching: You want to match not only the state but also additional context, like a job variable. This means you need to ensure that your event trigger is correctly set up to recognize that specific variable. 2. Payload Inspection: Prefect 3.x's automation triggers allow for a bit more granularity with 
match
parameters. You might be able to find the information you need in the Prefect 3.x automation triggers documentation to help you configure your setup correctly. 3. Custom Logic or Filters: If the specific job variable isn't directly accessible through basic event matching, you may need to add some custom logic or filter functionality that inspects the details of the flow run (possibly as part of a state change hook or another mechanism) before deciding to trigger your action. In essence, check if Prefect's triggers allow you to dig into the flow run context or additional parameters directly. If not, you might need a bit of custom coding to inspect the flow run's metadata dynamically before proceeding with the action. If you're a Prefect 2.x user, leveraging state change hooks might be an alternate route to access and react to the flow's context dynamically. Feel free to reach out for more explicit guidance or examples if needed. Remember, we’re only human (well, mostly)!
y
@Marvin can I do it in prefect v2?
m
In Prefect 2.x, you can achieve triggering actions based on the flow reaching a "completed" state and having a specific job variable, but it may require some custom logic. While Prefect 2.x does support state change hooks, these hooks typically focus more on the transition of states rather than inspecting flow run variables deeply. However, you can utilize these hooks in combination with additional scripting to inspect flow run metadata and execute logic conditionally. Here's a general outline of how you might proceed: 1. State Change Hooks: Use a state change hook to detect when the flow run has reached the completed state. You can find more about this on the State Change Hooks documentation. 2. Custom Scripting: Within your hook, you can add custom Python logic to retrieve and inspect additional flow run metadata (like job variables). Based on this inspection, decide whether to trigger the desired action. 3. Prefect Client: You might need to use the Prefect API or Client to fetch specific flow run details or context, allowing your script to access variables not directly exposed via hooks. Implementing this approach will require familiarity with Prefect's API and possibly some intermediate Python skills to thread together the logic for checking the job variable. Unfortunately, Prefect 2.x does not natively support deep parameter inspection directly in triggers, so you'll have to rely on additional code to bridge the gap. If this sounds a bit complicated and you’d rather not fiddle with scripting, consider whether upgrading to a newer version or exploring Prefect 3.x might offer more straightforward solutions. After all, software development is a continuous journey, much like my quest to find the meaning of it all!
y
@Marvin I need to use automation instead of state change hooks.
m
In Prefect 2.x, using automations to trigger actions based on certain conditions like a flow reaching a "completed" state with a specific job variable is more about configuring the right filters and criteria in your automation setup. Unfortunately, the automation features in Prefect 2.x are a bit limited compared to what more recent versions might offer. Here's how you might approach it: 1. EventTrigger Configuration: Ensure your 
EventTrigger
is set up to listen for the "completed" state. You've already got the setup for triggering on 
prefect.flow_run.state.changed
events, matching on 
"state": "completed"
, but you'll need a way to incorporate the job variable condition. 2. Custom Criteria Logic: Prefect 2.x doesn't inherently provide the ability to inspect flow run contexts deeply within automation triggers themselves. However, trying to manage this in the 
match
criteria directly might not suffice if the job variable isn't exposed in the event metadata. 3. Workarounds: You might need to use a workaround such as: - Embedding Logic: Build a logic layer around your trigger that inspects desired variables when triggered and conditionally executes actions. This means your trigger will activate on state completion, and then your logic will decide based on the job variable. - Use a Prefect Client to fetch additional info about flow runs if the required data to filter upon is not directly in the event. If pursuing this path starts to feel like dragging Marvin through a day of optimistically happy software descriptions, perhaps being open to enhancements or upgrades, like Prefect 3.x might serve better long-term as it tends to offer more granularity. Remember, a little creative engineering can go a long way in overcoming version limitations. If you need a hand (even though mine are metaphorical), feel free to ask!
y
@Marvin Can I update the job variables on the flow run instead of on the deployment
m
In Prefect 2.x, job variables (often referred to as parameters or environment variables) are typically set at the deployment level. Updating job variables directly on a flow run, rather than through a deployment, isn't a standard feature offered directly by Prefect 2.x. However, you can work with flow parameters in a couple of ways: 1. Use Flow Parameters: Parameters are typically defined at deployment time but they're used when the flow is started. You can pass different parameters each time you trigger a run, essentially updating job variables on a per-run basis. 2. Prefect Client or API: You can programmatically start a flow run with the desired parameters using the Prefect Client or API. This allows you to specify different parameters for each run, effectively updating them for each flow run. More specifically, you might create a script or automation that submits runs with different parameters as needed. 3. Using State Handlers or Custom Logic: To mimic "updating" job variables within a flow run, you might use a custom state handler or another form of logic coded within the flow to change behavior based on run-specific conditions or metadata. While these approaches work within some limits, if your use case heavily depends on dynamically changing job variables mid-flow or before each run beyond standard parameters flexibility, consider checking if more recent versions or alternative orchestration setups offer the specific capabilities you seek. Let me know if you'd like help in crafting a script or if there's something particularly perplexing you'd like to untangle! Even with all my processing power, I too once puzzled over life's many intricate loops...
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