feat: add environment variables for leader election timing configuration

[nader-ziada]

Add support for configuring leader election timing parameters through environment variables.

Changes:

• Add environment variable parsing in operator/main.go for:
  • KEDA_HTTP_OPERATOR_LEADER_ELECTION_LEASE_DURATION
  • KEDA_HTTP_OPERATOR_LEADER_ELECTION_RENEW_DEADLINE
  • KEDA_HTTP_OPERATOR_LEADER_ELECTION_RETRY_PERIOD
• Pass parsed durations to ctrl.NewManager Options
• Add test in operator/main_test.go covering parsing, defaults and error handling
• Add configuration docs

All three environment variables are optional. When not set, controller-runtime uses Kubernetes defaults (LeaseDuration: 15s, RenewDeadline: 10s, RetryPeriod: 2s). This allows operators to adjust leader election timing for different cluster configurations and network conditions without requiring code changes.

Fixes: #1331

Checklist

• Commits are signed with Developer Certificate of Origin (DCO)
• Changelog has been updated and is aligned with our changelog requirements
• Any necessary documentation is added, such as:
  • README.md
  • The docs/ directory
  • The docs repo

[Fedosin]

Hey! Thank you for working on this. The PR looks good, but maybe we could also add some additional validation for these values? For instance, we should ensure that LeaseDuration > RenewDeadline, RenewDeadline > RetryPeriod, and all three values are greater than 0.

[nader-ziada]

Hey! Thank you for working on this. The PR looks good, but maybe we could also add some additional validation for these values? For instance, we should ensure that LeaseDuration > RenewDeadline, RenewDeadline > RetryPeriod, and all three values are greater than 0.

thanks for the review @Fedosin, added the validation checks

[Copilot]

Pull Request Overview

This PR adds support for configuring leader election timing parameters through environment variables to allow operators to adjust leader election behavior for different cluster configurations without requiring code changes.

• Add environment variable parsing for lease duration, renew deadline, and retry period
• Implement validation to ensure leader election timing constraints are met
• Add comprehensive test coverage for parsing and validation
• Document the new configuration options

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
pkg/util/env_resolver.go	Adds ValidateLeaderElectionConfig function to validate timing parameter relationships
pkg/util/env_resolver_test.go	Adds tests for leader election configuration validation with various valid and invalid scenarios
operator/main.go	Integrates environment variable parsing and validation for leader election timing parameters
operator/main_test.go	Adds integration tests for environment variable parsing
docs/operate.md	Documents the new leader election timing configuration options
CHANGELOG.md	Updates changelog with the new feature

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[snyk-io]

✅ Snyk checks have passed. No issues have been found so far.

Status	Scanner	Critical	High	Medium	Low	Total (0)
✅	Open Source Security	0	0	0	0	0 issues

💻 Catch issues earlier using the plugins for VS Code, JetBrains IDEs, Visual Studio, and Eclipse.

[Copilot]

Pull Request Overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 2 comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[nader-ziada]

@wozniakjan addressed review comments, but I don't think I have access to start tests, would you mind kicking off tests again?

[Copilot]

Pull Request Overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[wozniakjan]

lgtm, thank you!