fix(emit): deterministic YAML via BTreeMap (kills agent apply-loop) - #281
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The controller's collector-yaml emit used `HashMap<String, Value>` for `processors`, `receivers`, `extensions`, `connectors`, `exporters`, and `pipelines`. serde_yaml iterates a HashMap in Rust's randomized order, so calling `emit_edge_yaml` / `emit_edge_yaml_5sketch_routing` / `emit_gateway_yaml` twice on the same input produced byte-different YAML strings — same semantic content, different key ordering. This broke the agent's opampextension byte-level no-op check (ASAPCollector#381 + the Issue #4 follow-up): the agent saw "incoming bytes != on-disk bytes" on every reconnect, applied, restarted, the controller pushed the SAME semantic config again, and the agent looped. 10+ restarts per smoke test before any sketch could flush. Fix: switch the six HashMap fields on `CollectorYaml` / `ServiceSection` to `BTreeMap`. BTreeMap iterates in key order; serde_yaml's emit is now deterministic. Same semantic content always serializes to the same bytes. Bonus: this matches the controller's broader content-addressed identity story — `PolicyFingerprint::from_config` already sorts its hash inputs into canonical order, and `SeriesIdResolver` keys are sorted attribute fingerprints. The emit was the last non-deterministic hop. The agent's no-op check (ASAPCollector PR for Issue #4) is still useful as defense-in-depth — handles non-controller OpAMP servers that might still push slightly different bytes for the same intent. Test plan: * `cargo test -p control_plane --lib`: 706/706 pass. * Empirically verified pre-fix: `curl /api/v1/collector-config/agent` twice → key ordering differs (processors block: countmin / countsketch / transform/keep_for_* appear in different positions). Post-fix: identical bytes across calls. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
Controller's YAML emit was non-deterministic (HashMap iteration order). Same semantic content emitted as byte-different YAML on each call. The agent's opampextension byte-level no-op check (ASAPCollector#381) saw "different bytes" on every reconnect, applied + restarted, the controller resent the same semantic config, and the agent looped forever. 10+ restarts per smoke test before any sketch could flush.
Fix: 6 HashMap fields on
CollectorYaml/ServiceSection→BTreeMap. Iterate in key order. Same semantic content always serializes to the same bytes.Matches the controller's content-addressed identity story (
PolicyFingerprint::from_configalready sorts hash inputs;SeriesIdResolverkeys are sorted attribute fingerprints). The emit was the last non-deterministic hop.Test plan
cargo test -p control_plane --lib→ 706/706 passcurl /api/v1/collector-config/agenttwice — pre-fix, key ordering differs; post-fix, identical bytes🤖 Generated with Claude Code