Edge validation uncovered broken templates

[shiroyasha]

After merging this, we have noticed that some templates are not working.

raw message:

I nuked my dev DB to verify that the template seeding is working properly after I made changes to the templates, and I get a No templates available screen when setting up my first canvas. Logs show this:

Failed to seed templates: create template Staged Release: rpc error: code = InvalidArgument desc = edge 2: source node component-node-3c9afc does not have output channel "default" (available: [success failure])


Looks like we had bad templates YAMLs, and now since we are validating the output channels on updates too ([#4362](https://github.com/superplanehq/superplane/pull/4362)), the seeding fails. So, the first you run SuperPlane (locally or self-hosted) you will have no templates available right now.

[superplane-leonardo]

🤖 Agent review started. I'm reading the issue and exploring the codebase now. A full review will be posted shortly.

[superplane-leonardo]

🤖 Automated Issue Review

Here is the review as a GitHub-flavored Markdown comment you can paste on the issue:

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Code review: edge validation and broken canvas templates (issue #4412)

1. Validity

The issue is valid and consistent with the code path.

• Seeding uses createTemplateCanvas → canvases.ParseCanvas, which validates edges via changesets.ValidateSourceNodeOutputChannel in pkg/grpc/actions/canvases/serialization.go (roughly the loop at lines 271–299).
• The log line matches the third edge in templates/canvases/staged-release.yaml (0-based edge 2): from component-node-3c9afc (HTTP) to merge-merge-vckyv1 (Merge) with channel: "default".
• The HTTP action declares only success and failure output channels (SuccessOutputChannel / FailureOutputChannel in pkg/components/http/http.go), not default — so validation correctly rejects that edge.

Reproduction: fresh DB → SeedTemplates → creation of the Staged Release template fails at parse/validation, Setup logs the warning and you end up with no seeded templates, matching the “No templates available” first-run experience.

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2. Location (codebase)

Area	Path / symbols
Failing template asset	templates/canvases/staged-release.yaml — node component-node-3c9afc / http-health-check--ping-server-spb8ma (HTTP), edges to Merge using channel: "default" where a success/failure split is required
Reference template (correct HTTP wiring)	templates/canvases/health-check-monitor.yaml — HTTP node edges use success and failure (not default to a downstream)
Edge validation	pkg/grpc/actions/canvases/serialization.go — ParseCanvas / edge loop calling changesets.ValidateSourceNodeOutputChannel
Error message	pkg/grpc/actions/canvases/changesets/output_channels.go — ValidateSourceNodeOutputChannel, listComponentOutputChannels
HTTP output channel definitions	pkg/components/http/http.go — OutputChannels (lines ~224–228) and SuccessOutputChannel / FailureOutputChannel constants (lines 33–34)
Template seeding	pkg/templates/seed.go — SeedTemplates, createTemplateCanvas (calls canvases.ParseCanvas)

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3. Complexity

• Level: Simple to medium (depends on how many templates are bad).
• Scope: The minimal fix is data-only for staged-release.yaml: relabel HTTP → Merge edges from default to success (and optionally add explicit failure edges if product-wise the merge should see failures). Compare with health-check-monitor.yaml for the intended pattern.
• Extra work (optional, larger): A CI or test that loads all templates/canvases/*.yaml through the same ParseCanvas path would prevent regressions; that’s a bit more work but still localized.

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4. Duplicates

• In-repo, the only other shipped canvas using the http action is health-check-monitor.yaml, which already uses success / failure correctly, so this does not look like a duplicate of another in-tree bug—more like one (or a few) stale YAMLs vs. strict validation after fix: validate canvas edge output channels on API writes #4362.
• No other local issue/PR was found in a quick gh search; treat GitHub as source of truth for “duplicate of #xxxx” if needed.

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5. Recommended approach

1. Fix templates/canvases/staged-release.yaml: For each edge whose source is an HTTP action (component-node-3c9afc, http-health-check--ping-server-spb8ma) and target is a Merge, set channel to success (and add failure edges to a sensible node if the canvas should handle HTTP failures, mirroring health-check-monitor if desired).
2. Grep the repo for name: "http" under templates/ and for edges with channel: "default" whose source is HTTP; fix any remaining instances the same way.
3. Optional hardening: Add a test (or a make target) that ParseCanvas’s all template YAMLs with the real registry so bad templates fail CI instead of at runtime for users.

No server-side relaxation of ValidateSourceNodeOutputChannel is required unless product intentionally allows legacy default for HTTP; the current behavior matches the http component contract.

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6. Human feedback from comments

• There is one comment, from @superplane-leonardo (bot): a placeholder that an agent review is in progress. No human reviewers have left scope changes, return-to-review reasons, or objections.
• There is nothing to reconcile from prior human review cycles; the issue body and linked PR fix: validate canvas edge output channels on API writes #4362 remain the authoritative context.

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[shiroyasha]

Nice! Lets add the CI check as well.