Support comma-separated -F for querying multiple facts

`node-lookup -jF ipaddress,enc_role` returned `{}` because it queried a single
fact literally named "ipaddress,enc_role". Requesting several facts per host is
a natural need (e.g. pairing an address with its role).

- Split -F on commas (splitFactNames) and match any of them via an "or" over
  ["=","name",<n>] clauses (nameFilter); a single name keeps the plain "="
  form.
- Key JSON output by each result's real fact name so all requested facts appear
  under the host (previously keyed by the raw -F string).
- Update the -F flag help and add unit tests (split, single vs multi query
  shape, multi-fact JSON).

main.go

@@ -110,6 +110,31 @@ type fact struct {
 	Value    json.RawMessage `json:"value"`
 }
 
+// splitFactNames splits a comma-separated -F value into trimmed, non-empty
+// names, so `-F ipaddress,enc_role` queries both facts.
+func splitFactNames(factName string) []string {
+	var names []string
+	for _, n := range strings.Split(factName, ",") {
+		if n = strings.TrimSpace(n); n != "" {
+			names = append(names, n)
+		}
+	}
+	return names
+}
+
+// nameFilter returns a PQL filter matching any of the given fact names: a plain
+// equality for one name, an "or" over per-name equalities for several.
+func nameFilter(names []string) []interface{} {
+	if len(names) == 1 {
+		return []interface{}{"=", "name", names[0]}
+	}
+	or := []interface{}{"or"}
+	for _, n := range names {
+		or = append(or, []interface{}{"=", "name", n})
+	}
+	return or
+}
+
 func buildQuery(node, factName, match, roleFact string, showRole, partial, inverse bool) string {
 	type filter = []interface{}
 	var filters []filter
@@ -117,8 +142,8 @@ func buildQuery(node, factName, match, roleFact string, showRole, partial, inver
 	if node != "" {
 		filters = append(filters, filter{"=", "certname", node})
 	}
-	if factName != "" {
-		filters = append(filters, filter{"=", "name", factName})
+	if names := splitFactNames(factName); len(names) > 0 {
+		filters = append(filters, nameFilter(names))
 	} else if showRole {
 		filters = append(filters, filter{"=", "name", roleFact})
 	}
@@ -326,12 +351,17 @@ func run(cfg config, nodeName, factName, match string, showRole, partial, invers
 			if _, ok := hostFactMap[f.Certname]; !ok {
 				hostFactMap[f.Certname] = map[string]interface{}{}
 			}
-			key := factName
+			// Key by the fact's actual name so multiple -F facts (e.g.
+			// ipaddress,enc_role) each appear under the host. Fall back to the
+			// computed key only if the result carries no name.
+			key := f.Name
 			if key == "" {
-				if showRole {
-					key = cfg.RoleFact
-				} else {
-					key = "value"
+				if key = factName; key == "" {
+					if showRole {
+						key = cfg.RoleFact
+					} else {
+						key = "value"
+					}
 				}
 			}
 			hostFactMap[f.Certname][key] = valueAny(f.Value)
@@ -426,7 +456,7 @@ func main() {
 
 	f := rootCmd.Flags()
 	f.StringVarP(&nodeName, "node", "n", "", "Node name")
-	f.StringVarP(&factName, "fact", "F", "", "Fact name")
+	f.StringVarP(&factName, "fact", "F", "", "Fact name (comma-separated for several, e.g. -F ipaddress,enc_role)")
 	f.BoolVarP(&showRole, "role", "R", false, "Show role fact ("+defaultRoleFact+" by default)")
 	f.StringVarP(&match, "match", "m", "", "Value to match (use with -p and/or -i)")
 	f.BoolVarP(&partial, "partial", "p", false, "Partial/regex match modifier (combine with -m)")