refactor: remove subdomains from dnslink fixtures

these concepts should not mix, and dnslinks should be testable
independent of --subdomain-url

i also added more useful export format for them, compatible with
IPNS_NS_MAP used by Boxo/Kubo/Rainbow

cmd/gateway-conformance/main.go

@@ -240,7 +240,7 @@ func main() {
 					},
 					&cli.BoolFlag{
 						Name:        "merged",
-						Usage:       "Merge the fixtures into a single CAR file",
+						Usage:       "Merge the CAR fixtures into a single CAR file",
 						Value:       false,
 						Destination: &merged,
 					},
@@ -256,44 +256,41 @@ func main() {
 						return err
 					}
 
+					// IPNS Records
+					err = copyFiles(fxs.IPNSRecords, directory)
+					if err != nil {
+						return err
+					}
+
+					// DNSLink fixtures as YAML, JSON, and IPNS_NS_MAP env variable
+					err = copyFiles(fxs.ConfigFiles, directory)
+					if err != nil {
+						return err
+					}
+					err = dnslink.MergeJSON(fxs.ConfigFiles, filepath.Join(directory, "dnslinks.json"))
+					if err != nil {
+						return err
+					}
+					err = dnslink.MergeNsMapEnv(fxs.ConfigFiles, filepath.Join(directory, "dnslinks.IPFS_NS_MAP"))
+					if err != nil {
+						return err
+					}
+
 					merged := cCtx.Bool("merged")
 					if merged {
+						// All .car fixtures merged into a single .car file
 						err = car.Merge(fxs.CarFiles, filepath.Join(directory, "fixtures.car"))
 						if err != nil {
 							return err
 						}
-
-						err := dnslink.Merge(fxs.ConfigFiles, filepath.Join(directory, "dnslinks.json"))
-						if err != nil {
-							return err
-						}
-
 						// TODO: when https://github.com/ipfs/specs/issues/369 has been completed,
-						// merge the IPNS records into a car file.
-						err = copyFiles(fxs.IPNSRecords, directory)
-						if err != nil {
-							return err
-						}
+						// implement merge support to include the IPNS records in the car file.
 					} else {
+						// Copy .car fixtures as -is
 						err = copyFiles(fxs.CarFiles, directory)
 						if err != nil {
 							return err
 						}
-
-						err = copyFiles(fxs.ConfigFiles, directory)
-						if err != nil {
-							return err
-						}
-
-						err = copyFiles(fxs.IPNSRecords, directory)
-						if err != nil {
-							return err
-						}
-
-						err := dnslink.Merge(fxs.ConfigFiles, filepath.Join(directory, "dnslinks.json"))
-						if err != nil {
-							return err
-						}
 					}
 
 					return nil

tooling/dnslink/dnslink.go

@@ -15,9 +15,8 @@ type ConfigFixture struct {
 }
 
 type DNSLink struct {
-	Subdomain string `yaml:"subdomain"`
-	Domain    string `yaml:"domain"`
-	Path      string `yaml:"path"`
+	Domain string `yaml:"domain"`
+	Path   string `yaml:"path"`
 }
 
 func InlineDNS(s string) string {
@@ -57,19 +56,13 @@ func (d *ConfigFixture) MustGet(id string) string {
 	if !ok {
 		panic(fmt.Errorf("dnslink %s not found", id))
 	}
-	if dnsLink.Domain != "" && dnsLink.Subdomain != "" {
-		panic(fmt.Errorf("dnslink %s has both domain and subdomain", id))
-	}
-	if dnsLink.Domain == "" && dnsLink.Subdomain == "" {
-		panic(fmt.Errorf("dnslink %s has neither domain nor subdomain", id))
+	if dnsLink.Domain == "" {
+		panic(fmt.Errorf("dnslink %s has no domain", id))
 	}
 	if dnsLink.Path == "" {
 		panic(fmt.Errorf("dnslink %s has no path", id))
 	}
 
-	if dnsLink.Domain != "" {
-		return dnsLink.Domain
-	}
+	return dnsLink.Domain
 
-	return dnsLink.Subdomain
 }

tooling/dnslink/merge.go

@@ -4,17 +4,16 @@ import (
 	"encoding/json"
 	"fmt"
 	"os"
+	"strings"
 )
 
 type DNSLinksAggregate struct {
-	Domains    map[string]string `json:"domains"`
-	Subdomains map[string]string `json:"subdomains"`
+	Domains map[string]string `json:"domains"`
 }
 
 func Aggregate(inputPaths []string) (*DNSLinksAggregate, error) {
 	agg := DNSLinksAggregate{
-		Domains:    make(map[string]string),
-		Subdomains: make(map[string]string),
+		Domains: make(map[string]string),
 	}
 
 	for _, file := range inputPaths {
@@ -24,34 +23,19 @@ func Aggregate(inputPaths []string) (*DNSLinksAggregate, error) {
 		}
 
 		for _, link := range dnsLinks.DNSLinks {
-			if link.Domain != "" && link.Subdomain != "" {
-				return nil, fmt.Errorf("dnslink %s has both domain and subdomain", link.Subdomain)
+			if _, ok := agg.Domains[link.Domain]; ok {
+				return nil, fmt.Errorf("collision detected for domain %s", link.Domain)
 			}
 
-			if link.Domain != "" {
-				if _, ok := agg.Domains[link.Domain]; ok {
-					return nil, fmt.Errorf("collision detected for domain %s", link.Domain)
-				}
-
-				agg.Domains[link.Domain] = link.Path
-				continue
-			}
-
-			if link.Subdomain != "" {
-				if _, ok := agg.Subdomains[link.Subdomain]; ok {
-					return nil, fmt.Errorf("collision detected for subdomain %s", link.Subdomain)
-				}
-
-				agg.Subdomains[link.Subdomain] = link.Path
-				continue
-			}
+			agg.Domains[link.Domain] = link.Path
+			continue
 		}
 	}
 
 	return &agg, nil
 }
 
-func Merge(inputPaths []string, outputPath string) error {
+func MergeJSON(inputPaths []string, outputPath string) error {
 	kvs, err := Aggregate(inputPaths)
 	if err != nil {
 		return err
@@ -65,3 +49,22 @@ func Merge(inputPaths []string, outputPath string) error {
 	err = os.WriteFile(outputPath, j, 0644)
 	return err
 }
+
+// MergeEnv produces a string compatible with IPFS_NS_MAP env veriable syntax
+// which can be used by tools to pre-populate namesys (IPNS, DNSLink) resolution
+// results to facilitate tests based on static fixtures.
+func MergeNsMapEnv(inputPaths []string, outputPath string) error {
+	kvs, err := Aggregate(inputPaths)
+	if err != nil {
+		return err
+	}
+
+	var result []string
+	for key, value := range kvs.Domains {
+		result = append(result, fmt.Sprintf("%s:%s", key, value))
+	}
+	nsMapValue := strings.Join(result, ",")
+
+	err = os.WriteFile(outputPath, []byte(nsMapValue), 0644)
+	return err
+}