Add host specific headers

Allows configuring headers per registry host

Signed-off-by: Derek McGowan <derek@mcg.dev>

remotes/docker/config/hosts.go

@@ -48,6 +48,8 @@ type hostConfig struct {
 	clientPairs [][2]string
 	skipVerify  *bool
 
+	header http.Header
+
 	// TODO: API ("docker" or "oci")
 	// TODO: API Version ("v1", "v2")
 	// TODO: Add credential configuration (domain alias, username)
@@ -143,6 +145,7 @@ func ConfigureHosts(ctx context.Context, options HostOptions) docker.RegistryHos
 			rhosts[i].Host = host.host
 			rhosts[i].Path = host.path
 			rhosts[i].Capabilities = host.capabilities
+			rhosts[i].Header = host.header
 
 			if host.caCerts != nil || host.clientPairs != nil || host.skipVerify != nil {
 				tr := defaultTransport.Clone()
@@ -203,7 +206,6 @@ func ConfigureHosts(ctx context.Context, options HostOptions) docker.RegistryHos
 				rhosts[i].Client = client
 				rhosts[i].Authorizer = authorizer
 			}
-
 		}
 
 		return rhosts, nil
@@ -274,6 +276,8 @@ type hostFileConfig struct {
 
 	SkipVerify *bool `toml:"skip_verify"`
 
+	Header map[string]toml.Primitive `toml:"header"`
+
 	// API (default: "docker")
 	// API Version (default: "v2")
 	// Credentials: helper? name? username? alternate domain? token?
@@ -433,6 +437,31 @@ func parseHostsFile(ctx context.Context, baseDir string, b []byte) ([]hostConfig
 				return nil, errors.Errorf("invalid type %v for \"client\"", t)
 			}
 		}
+
+		headerKey := append(baseKey, "header")
+		if md.IsDefined(headerKey...) {
+			header := http.Header{}
+			for key, prim := range hostConfig.Header {
+				switch t := md.Type(append(headerKey, key)...); t {
+				case "String":
+					var value string
+					if err := md.PrimitiveDecode(prim, &value); err != nil {
+						return nil, errors.Wrapf(err, "failed to decode header %q", key)
+					}
+					header[key] = []string{value}
+				case "Array":
+					var value []string
+					if err := md.PrimitiveDecode(prim, &value); err != nil {
+						return nil, errors.Wrapf(err, "failed to decode header %q", key)
+					}
+
+					header[key] = value
+				default:
+					return nil, errors.Errorf("invalid type %v for header %q", t, key)
+				}
+			}
+			hosts[i].header = header
+		}
 	}
 
 	return hosts, nil

remotes/docker/config/hosts_test.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
+	"net/http"
 	"path/filepath"
 	"testing"
 
@@ -76,11 +77,15 @@ func TestParseHostFile(t *testing.T) {
 	const testtoml = `
 server = "https://test-default.registry"
 ca = "/etc/path/default"
+[header]
+  x-custom-1 = "custom header"
 
 [host."https://mirror.registry"]
   capabilities = ["pull"]
   ca = "/etc/certs/mirror.pem"
   skip_verify = false
+  [host."https://mirror.registry".header]
+    x-custom-2 = ["value1", "value2"]
 
 [host."https://mirror-bak.registry/us"]
   capabilities = ["pull"]
@@ -109,6 +114,7 @@ ca = "/etc/path/default"
 			capabilities: docker.HostCapabilityPull,
 			caCerts:      []string{filepath.FromSlash("/etc/certs/mirror.pem")},
 			skipVerify:   &fb,
+			header:       http.Header{"x-custom-2": {"value1", "value2"}},
 		},
 		{
 			scheme:       "https",
@@ -159,6 +165,7 @@ ca = "/etc/path/default"
 			path:         "/v2",
 			capabilities: allCaps,
 			caCerts:      []string{filepath.FromSlash("/etc/path/default")},
+			header:       http.Header{"x-custom-1": {"custom header"}},
 		},
 	}
 	hosts, err := parseHostsFile(ctx, "", []byte(testtoml))
@@ -241,6 +248,20 @@ func compareHostConfig(j, k hostConfig) bool {
 		return false
 	}
 
+	if len(j.header) != len(k.header) {
+		return false
+	}
+	for key := range j.header {
+		if len(j.header[key]) != len(k.header[key]) {
+			return false
+		}
+		for i := range j.header[key] {
+			if j.header[key][i] != k.header[key][i] {
+				return false
+			}
+		}
+	}
+
 	return true
 }
 
@@ -258,6 +279,7 @@ func printHostConfig(hc []hostConfig) string {
 		} else {
 			fmt.Fprintf(b, "\t\tskip-verify: %t\n", *hc[i].skipVerify)
 		}
+		fmt.Fprintf(b, "\t\theader: %#v\n", hc[i].header)
 	}
 	return b.String()
 }

remotes/docker/registry.go

@@ -70,6 +70,7 @@ type RegistryHost struct {
 	Scheme       string
 	Path         string
 	Capabilities HostCapabilities
+	Header       http.Header
 }
 
 // RegistryHosts fetches the registry hosts for a given namespace,

remotes/docker/resolver.go

@@ -450,6 +450,9 @@ func (r *dockerBase) request(host RegistryHost, method string, ps ...string) *re
 	for key, value := range r.header {
 		header[key] = append(header[key], value...)
 	}
+	for key, value := range host.Header {
+		header[key] = append(header[key], value...)
+	}
 	parts := append([]string{"/", host.Path, r.namespace}, ps...)
 	p := path.Join(parts...)
 	// Join strips trailing slash, re-add ending "/" if included