feat: add TTL strategy to Argo WorkflowTemplates

[npow]

Summary

• Add TTL strategy support to Argo WorkflowTemplates via METAFLOW_ARGO_WORKFLOW_TTL_SECONDS config
• Automatically cleans up completed workflow pods after the configured TTL, reducing cluster resource usage
• Fix: revert CronWorkflow schedules array back to schedule string field for broader Argo version compatibility

Test plan

• test/unit/test_argo_ttl_strategy.py — unit tests for TTL strategy configuration

🤖 Generated with Claude Code

[greptile-apps]

Greptile Summary

This PR adds ttlStrategy support to Argo WorkflowTemplate specs, controlled by a new METAFLOW_ARGO_WORKFLOWS_TTL_SECONDS_AFTER_COMPLETION config variable (default: 7 days). The implementation is clean and well-tested, but the non-zero default is a silent behavior change — existing users who upgrade will have completed workflow resources auto-deleted after 7 days without any explicit opt-in.

Confidence Score: 5/5

Safe to merge; all findings are P2 style/suggestion level.

The implementation is correct and tested. The two findings are both P2: one is a design preference (default TTL value), and the other is a minor code quality improvement (double int() call). Neither blocks correctness.

Review the default value in metaflow/metaflow_config.py — consider whether 0 (opt-out) is safer than 7 days (opt-in) for the default TTL.

Important Files Changed

Filename	Overview
metaflow/metaflow_config.py	Adds ARGO_WORKFLOWS_TTL_SECONDS_AFTER_COMPLETION config; default of 7 days is a silent behavior change for existing users.
metaflow/plugins/argo/argo_workflows.py	Adds ttl_strategy() to WorkflowSpec and wires it into the WorkflowTemplate builder; logic is correct, minor int() redundancy.
test/unit/test_argo_ttl_strategy.py	Good coverage of positive, zero, None, negative, string-input, and chaining cases for ttl_strategy().

_{Reviews (1): Last reviewed commit: "test: add unit tests for WorkflowSpec.tt..." | Re-trigger Greptile}

[greptile-apps]

Opt-in default TTL is a behavior change for existing users

The default of 7 days means every existing Metaflow user who upgrades will silently start having their completed Argo Workflow resources auto-deleted after 7 days. Users who rely on workflow history beyond that window (e.g. for audit, debugging, or custom tooling that queries old workflow objects) will lose it without any explicit action. A safer default might be None or 0 (disable TTL) to preserve the existing behavior, with opt-in for cleanup.

[greptile-apps]

int() called twice and raises unhandled ValueError on bad env-var input

int(seconds_after_completion) is evaluated twice (once in the condition, once in the payload). More importantly, if a user sets METAFLOW_ARGO_WORKFLOWS_TTL_SECONDS_AFTER_COMPLETION=invalid in their environment, int("invalid") will raise an unhandled ValueError at deploy time with no helpful message. Converting and validating once at the top is cleaner:

Suggested change

	def ttl_strategy(self, seconds_after_completion):
	# https://argoproj.github.io/argo-workflows/fields/#ttlstrategy
	if seconds_after_completion is not None and int(seconds_after_completion) > 0:
	self.payload["ttlStrategy"] = {
	"secondsAfterCompletion": int(seconds_after_completion)
	}
	return self
	def ttl_strategy(self, seconds_after_completion):
	# https://argoproj.github.io/argo-workflows/fields/#ttlstrategy
	if seconds_after_completion is not None:
	try:
	seconds = int(seconds_after_completion)
	except (TypeError, ValueError):
	seconds = 0
	if seconds > 0:
	self.payload["ttlStrategy"] = {
	"secondsAfterCompletion": seconds
	}
	return self