#Add Graph Presentation To A Topology

#Question

How should a topology producer add polished graph presentation to netdata.topology.v1 without making the UI domain-specific?

#Inputs

• A topology producer that emits netdata.topology.v1.
• Actor and link compact tables with required type columns.
• Type registry entries under data.types.
• Optional evidence and actor-detail tables used by port bullets or highlight-path behavior.

#Schema Choices

• Put actor visuals in data.types.actor_types.<id>.presentation.
• Put link visuals in data.types.link_types.<id>.presentation.
• Put port bullet visuals in data.types.port_types.<id>.presentation.
• Put cross-type graph behavior in data.presentation.
• Use only schema-defined tokens for colors, icons, opacity, width, line style, curves, and arrows.
• Use label_policy.columns for actor labels. Do not use canonical identity arrays as display text.
• Use ports.sources[] when ports.show_bullets is true.
• Use selection.actor_click.mode: highlight_path only with path table, path-member actor-column, and order-column references. Add an owner actor column when the same table stores different paths for different clicked actors.

#Implementation Steps

1. Define type-level presentation for every actor type that should have a domain-specific visual profile.
2. Define link presentation for every renderable link type, including direction arrow and curve tokens.
3. Define port_types and ports.sources[] together:
   • source: links reads bullets from the graph links table;
   • source: evidence reads bullets from a named evidence type;
   • source: actor_table reads bullets from a named actor detail table.
4. Make name_column a scalar display column. Do not use actor_ref, link_ref, evidence_ref, array, or json as bullet labels.
5. Add graph-level data.presentation.legend, port_fields, scale_keys, and selection.actor_click.
6. Update producer tests or fixtures so the new presentation path is exercised.

#Validation

• Validate JSON against src/plugins.d/FUNCTION_TOPOLOGY_SCHEMA.json.
• Run topologyv1.ValidateDecodedResponse() or the function-validation tool so semantic references are checked.
• Add negative tests for:
  • missing label-policy columns;
  • non-display label columns;
  • missing port-bullet source tables;
  • bad highlight-path columns;
  • invalid token values.
• Check C producers with the compile command from build/compile_commands.json using -fsyntax-only when a full local build is blocked.

#Gotchas

• Presentation is production payload data, not compatibility reconstruction data.
• Type ids are producer-local until Cloud aggregation namespaces and canonicalizes them.
• profile_version is diagnostic. Do not use it to drop facts or rows.
• If a presentation source depends on optional runtime data, still declare a stable table/evidence type so validators can catch typos.
• Sensitive identifiers may exist in topology detail tables. Do not reference them in label_policy, graph hover, port bullet labels, logs, docs, SOWs, or durable review artifacts.