checker: add domain length validation and refactor rules into per-concern checks

checker/rules_helpers.go

@@ -0,0 +1,94 @@
+package checker
+
+import (
+	"context"
+	"fmt"
+
+	sdk "git.happydns.org/checker-sdk-go/checker"
+)
+
+// loadXMPPData fetches the XMPP observation. On error, returns a CheckState
+// the caller should emit to short-circuit its rule.
+func loadXMPPData(ctx context.Context, obs sdk.ObservationGetter) (*XMPPData, *sdk.CheckState) {
+	var data XMPPData
+	if err := obs.Get(ctx, ObservationKeyXMPP, &data); err != nil {
+		return nil, &sdk.CheckState{
+			Status:  sdk.StatusError,
+			Message: fmt.Sprintf("failed to load XMPP observation: %v", err),
+			Code:    "xmpp.observation_error",
+		}
+	}
+	return &data, nil
+}
+
+// wantsFromOpts reads the "mode" option and returns (wantC2S, wantS2S).
+// Defaults to "both" when unset or invalid.
+func wantsFromOpts(opts sdk.CheckerOptions) (bool, bool) {
+	mode, _ := sdk.GetOption[string](opts, "mode")
+	if mode == "" {
+		mode = "both"
+	}
+	return mode != "s2s", mode != "c2s"
+}
+
+// statesFromIssues turns a list of derived Issues into CheckStates.
+func statesFromIssues(issues []Issue) []sdk.CheckState {
+	out := make([]sdk.CheckState, 0, len(issues))
+	for _, is := range issues {
+		out = append(out, issueToState(is))
+	}
+	return out
+}
+
+func issueToState(is Issue) sdk.CheckState {
+	st := sdk.CheckState{
+		Status:  severityToStatus(is.Severity),
+		Message: is.Message,
+		Code:    is.Code,
+		Subject: is.Endpoint,
+	}
+	if is.Fix != "" {
+		st.Meta = map[string]any{"fix": is.Fix}
+	}
+	return st
+}
+
+func passState(code, message string) sdk.CheckState {
+	return sdk.CheckState{Status: sdk.StatusOK, Message: message, Code: code}
+}
+
+func notTestedState(code, message string) sdk.CheckState {
+	return sdk.CheckState{Status: sdk.StatusUnknown, Message: message, Code: code}
+}
+
+func severityToStatus(sev string) sdk.Status {
+	switch sev {
+	case SeverityCrit:
+		return sdk.StatusCrit
+	case SeverityWarn:
+		return sdk.StatusWarn
+	case SeverityInfo:
+		return sdk.StatusInfo
+	default:
+		return sdk.StatusOK
+	}
+}
+
+// filterIssuesByCodes returns only the issues whose Code is in the given set,
+// preserving their original order.
+func filterIssuesByCodes(issues []Issue, codes ...string) []Issue {
+	if len(codes) == 0 || len(issues) == 0 {
+		return nil
+	}
+	set := make(map[string]struct{}, len(codes))
+	for _, c := range codes {
+		set[c] = struct{}{}
+	}
+	var out []Issue
+	for _, is := range issues {
+		if _, ok := set[is.Code]; ok {
+			out = append(out, is)
+		}
+	}
+	return out
+}