Initial commit

checker/rules_common.go

@@ -0,0 +1,75 @@
+package checker
+
+import (
+	"context"
+	"fmt"
+
+	sdk "git.happydns.org/checker-sdk-go/checker"
+)
+
+// Defaults are centralised so Definition's docs and runtime reads cannot drift.
+const (
+	defaultMaxChainLength          = 8
+	defaultMinTargetTTL            = 60
+	defaultRequireResolvableTarget = true
+	defaultAllowApexCNAME          = false
+	defaultRecognizeApexFlattening = true
+
+	// hintKey is the CheckState.Meta key the HTML report reads to render the
+	// "How to fix" block: keep them in sync.
+	hintKey = "hint"
+)
+
+func loadAlias(ctx context.Context, obs sdk.ObservationGetter) (*AliasData, []sdk.CheckState) {
+	var data AliasData
+	if err := obs.Get(ctx, ObservationKeyAlias, &data); err != nil {
+		return nil, []sdk.CheckState{{
+			Status:  sdk.StatusError,
+			Message: fmt.Sprintf("failed to read alias observation: %v", err),
+		}}
+	}
+	return &data, nil
+}
+
+// skipped is the "nothing to judge right now" return: rules must produce at
+// least one state, otherwise the SDK substitutes StatusUnknown.
+func skipped(reason string) []sdk.CheckState {
+	return []sdk.CheckState{{
+		Status:  sdk.StatusUnknown,
+		Message: "skipped: " + reason,
+	}}
+}
+
+func okState(subject, message string) []sdk.CheckState {
+	return []sdk.CheckState{{
+		Status:  sdk.StatusOK,
+		Subject: subject,
+		Message: message,
+	}}
+}
+
+// withHint is a no-op when hint is empty so callers can pass through unchecked.
+func withHint(s sdk.CheckState, hint string) sdk.CheckState {
+	if hint == "" {
+		return s
+	}
+	if s.Meta == nil {
+		s.Meta = map[string]any{}
+	}
+	s.Meta[hintKey] = hint
+	return s
+}
+
+// apexKnown gates chain-oriented rules with a uniform "apex lookup failed"
+// skip line so the UI stays consistent across rules.
+func apexKnown(data *AliasData) bool {
+	return data.ApexLookupError == "" && data.Apex != ""
+}
+
+func allowApexCNAME(opts sdk.CheckerOptions) bool {
+	return sdk.GetBoolOption(opts, "allowApexCNAME", defaultAllowApexCNAME)
+}
+
+func recognizeApexFlattening(opts sdk.CheckerOptions) bool {
+	return sdk.GetBoolOption(opts, "recognizeApexFlattening", defaultRecognizeApexFlattening)
+}