feat(auth): add httptransport package (#8567)

This package is the equivalent of google.golang.org/api/transport/http for the new auth library. The biggest different is the main function does not return an endpoint so we will want to add a helper in gax or somewhere for this. Also, there are is an extra helper to add a TokenProvider to a http.Client which should elevate some user needs for extra extensibility of a client. They can simply customize away and user the helper to add auth.
googleapis · Sep 13, 2023 · 6898597 · 6898597
1 parent e4a54cd
commit 6898597
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Showing 10 changed files with 1,108 additions and 61 deletions.
diff --git a/auth/detect/internal/impersonate/impersonate.go b/auth/detect/internal/impersonate/impersonate.go
@@ -24,11 +24,11 @@ import (
 
 	"cloud.google.com/go/auth"
 	"cloud.google.com/go/auth/internal"
-	"cloud.google.com/go/auth/internal/transport"
 )
 
 const (
 	defaultTokenLifetime = "3600s"
+	authHeaderKey        = "Authorization"
 )
 
 // generateAccesstokenReq is used for service account impersonation
@@ -93,7 +93,7 @@ func (tp *Options) Token(ctx context.Context) (*auth.Token, error) {
 		return nil, fmt.Errorf("detect: unable to create impersonation request: %w", err)
 	}
 	req.Header.Set("Content-Type", "application/json")
-	if err := transport.SetAuthHeader(ctx, tp.Tp, req); err != nil {
+	if err := setAuthHeader(ctx, tp.Tp, req); err != nil {
 		return nil, err
 	}
 	resp, err := tp.Client.Do(req)
@@ -123,3 +123,16 @@ func (tp *Options) Token(ctx context.Context) (*auth.Token, error) {
 		Type:   internal.TokenTypeBearer,
 	}, nil
 }
+
+func setAuthHeader(ctx context.Context, tp auth.TokenProvider, r *http.Request) error {
+	t, err := tp.Token(ctx)
+	if err != nil {
+		return err
+	}
+	typ := t.Type
+	if typ == "" {
+		typ = internal.TokenTypeBearer
+	}
+	r.Header.Set(authHeaderKey, typ+" "+t.Value)
+	return nil
+}
diff --git a/auth/go.mod b/auth/go.mod
@@ -5,6 +5,12 @@ go 1.19
 require (
 	cloud.google.com/go/compute/metadata v0.2.3
 	github.com/google/go-cmp v0.5.9
+	go.opencensus.io v0.24.0
+	golang.org/x/net v0.14.0
 )
 
-require cloud.google.com/go/compute v1.14.0 // indirect
+require (
+	cloud.google.com/go/compute v1.19.1 // indirect
+	github.com/golang/groupcache v0.0.0-20200121045136-8c9f03a8e57e // indirect
+	golang.org/x/text v0.12.0 // indirect
+)
diff --git a/auth/go.sum b/auth/go.sum
@@ -1,6 +1,103 @@
-cloud.google.com/go/compute v1.14.0 h1:hfm2+FfxVmnRlh6LpB7cg1ZNU+5edAHmW679JePztk0=
-cloud.google.com/go/compute v1.14.0/go.mod h1:YfLtxrj9sU4Yxv+sXzZkyPjEyPBZfXHUvjxega5vAdo=
+cloud.google.com/go v0.26.0/go.mod h1:aQUYkXzVsufM+DwF1aE+0xfcU+56JwCaLick0ClmMTw=
+cloud.google.com/go/compute v1.19.1 h1:am86mquDUgjGNWxiGn+5PGLbmgiWXlE/yNWpIpNvuXY=
+cloud.google.com/go/compute v1.19.1/go.mod h1:6ylj3a05WF8leseCdIf77NK0g1ey+nj5IKd5/kvShxE=
 cloud.google.com/go/compute/metadata v0.2.3 h1:mg4jlk7mCAj6xXp9UJ4fjI9VUI5rubuGBW5aJ7UnBMY=
 cloud.google.com/go/compute/metadata v0.2.3/go.mod h1:VAV5nSsACxMJvgaAuX6Pk2AawlZn8kiOGuCv6gTkwuA=
+github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
+github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
+github.com/client9/misspell v0.3.4/go.mod h1:qj6jICC3Q7zFZvVWo7KLAzC3yx5G7kyvSDkc90ppPyw=
+github.com/cncf/udpa/go v0.0.0-20191209042840-269d4d468f6f/go.mod h1:M8M6+tZqaGXZJjfX53e64911xZQV5JYwmTeXPW+k8Sc=
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diff --git a/auth/httptransport/httptransport.go b/auth/httptransport/httptransport.go
@@ -0,0 +1,188 @@
+// Copyright 2023 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package httptransport
+
+import (
+	"crypto/tls"
+	"errors"
+	"fmt"
+	"net/http"
+
+	"cloud.google.com/go/auth"
+	"cloud.google.com/go/auth/detect"
+	"cloud.google.com/go/auth/internal"
+	"cloud.google.com/go/auth/internal/transport"
+)
+
+// ClientCertProvider is a function that returns a TLS client certificate to be
+// used when opening TLS connections. It follows the same semantics as
+// [crypto/tls.Config.GetClientCertificate].
+type ClientCertProvider = func(*tls.CertificateRequestInfo) (*tls.Certificate, error)
+
+// Options used to configure a [net/http.Client] from [NewClient].
+type Options struct {
+	// DisableTelemetry disables default telemetry (OpenCensus). An example
+	// reason to do so would be to bind custom telemetry that overrides the
+	// defaults.
+	DisableTelemetry bool
+	// DisableAuthentication specifies that no authentication should be used. It
+	// is suitable only for testing and for accessing public resources, like
+	// public Google Cloud Storage buckets.
+	DisableAuthentication bool
+	// Headers are extra HTTP headers that will be appended to every outgoing
+	// request.
+	Headers http.Header
+	// Endpoint overrides the default endpoint to be used for a service.
+	Endpoint string
+	// APIKey specifies an API key to be used as the basis for authentication.
+	// If set DetectOpts are ignored.
+	APIKey string
+	// TokenProvider specifies the provider used to add Authorization header to
+	// all requests. If set DetectOpts are ignored.
+	TokenProvider auth.TokenProvider
+	// ClientCertProvider is a function that returns a TLS client certificate to
+	// be used when opening TLS connections. It follows the same semantics as
+	// crypto/tls.Config.GetClientCertificate.
+	ClientCertProvider ClientCertProvider
+	// DetectOpts configures settings for detect Application Default
+	// Credentials.
+	DetectOpts *detect.Options
+
+	// InternalOptions are NOT meant to be set directly by consumers of this
+	// package, they should only be set by generated client code.
+	InternalOptions *InternalOptions
+}
+
+func (o *Options) validate() error {
+	if o == nil {
+		return errors.New("httptransport: opts required to be non-nil")
+	}
+	hasCreds := o.APIKey != "" ||
+		o.TokenProvider != nil ||
+		(o.DetectOpts != nil && len(o.DetectOpts.CredentialsJSON) > 0) ||
+		(o.DetectOpts != nil && o.DetectOpts.CredentialsFile != "")
+	if o.DisableAuthentication && hasCreds {
+		return errors.New("httptransport: DisableAuthentication is incompatible with options that set or detect credentials")
+	}
+	return nil
+}
+
+// client returns the client a user set for the detect options or nil if one was
+// not set.
+func (o *Options) client() *http.Client {
+	if o.DetectOpts != nil && o.DetectOpts.Client != nil {
+		return o.DetectOpts.Client
+	}
+	return nil
+}
+
+func (o *Options) resolveDetectOptions() *detect.Options {
+	io := o.InternalOptions
+	// soft-clone these so we are not updating a ref the user holds and may reuse
+	do := transport.CloneDetectOptions(o.DetectOpts)
+
+	// If scoped JWTs are enabled user provided an aud, allow self-signed JWT.
+	if (io != nil && io.EnableJWTWithScope) || do.Audience != "" {
+		do.UseSelfSignedJWT = true
+	}
+	// Only default scopes if user did not also set an audience.
+	if len(do.Scopes) == 0 && do.Audience == "" && io != nil && len(io.DefaultScopes) > 0 {
+		do.Scopes = make([]string, len(io.DefaultScopes))
+		copy(do.Scopes, io.DefaultScopes)
+	}
+	if len(do.Scopes) == 0 && do.Audience == "" && io != nil {
+		do.Audience = o.InternalOptions.DefaultAudience
+	}
+	return do
+}
+
+// InternalOptions are only meant to be set by generated client code. These are
+// not meant to be set directly by consumers of this package. Configuration in
+// this type is considered EXPERIMENTAL and may be removed at any time in the
+// future without warning.
+type InternalOptions struct {
+	// EnableJWTWithScope specifies if scope can be used with self-signed JWT.
+	EnableJWTWithScope bool
+	// DefaultAudience specifies a default audience to be used as the audience
+	// field ("aud") for the JWT token authentication.
+	DefaultAudience string
+	// DefaultEndpoint specifies the default endpoint.
+	DefaultEndpoint string
+	// DefaultMTLSEndpoint specifies the default mTLS endpoint.
+	DefaultMTLSEndpoint string
+	// DefaultScopes specifies the default OAuth2 scopes to be used for a
+	// service.
+	DefaultScopes []string
+}
+
+// AddAuthorizationMiddleware adds a middleware to the provided client's
+// transport that sets the Authorization header with the value produced by the
+// provided [cloud.google.com/go/auth.TokenProvider]. An error is returned only
+// if client or tp is nil.
+func AddAuthorizationMiddleware(client *http.Client, tp auth.TokenProvider) error {
+	if client == nil || tp == nil {
+		return fmt.Errorf("httptransport: client and tp must not be nil")
+	}
+	base := client.Transport
+	if base == nil {
+		base = http.DefaultTransport.(*http.Transport).Clone()
+	}
+	client.Transport = &authTransport{
+		provider: auth.NewCachedTokenProvider(tp, nil),
+		base:     base,
+	}
+	return nil
+}
+
+// NewClient returns a [net/http.Client] that can be used to communicate with a
+// Google cloud service, configured with the provided [Options]. It
+// automatically appends Authorization headers to all outgoing requests.
+func NewClient(opts *Options) (*http.Client, error) {
+	if err := opts.validate(); err != nil {
+		return nil, err
+	}
+	// TODO(codyoss): re-add in a future PR
+
+	// tOpts := &transport.Options{
+	// 	Endpoint:           opts.Endpoint,
+	// 	ClientCertProvider: opts.ClientCertProvider,
+	// 	Client:             opts.client(),
+	// }
+	// if io := opts.InternalOptions; io != nil {
+	// 	tOpts.DefaultEndpoint = io.DefaultEndpoint
+	// 	tOpts.DefaultMTLSEndpoint = io.DefaultMTLSEndpoint
+	// }
+	// clientCertProvider, dialTLSContext, err := transport.GetHTTPTransportConfig(tOpts)
+	// if err != nil {
+	// 	return nil, err
+	// }
+	trans, err := newTransport(defaultBaseTransport(nil), opts)
+	if err != nil {
+		return nil, err
+	}
+	return &http.Client{
+		Transport: trans,
+	}, nil
+}
+
+// SetAuthHeader uses the provided token to set the Authorization header on a
+// request. If the token.Type is empty, the type is assumed to be Bearer.
+func SetAuthHeader(token *auth.Token, req *http.Request) {
+	typ := token.Type
+	if typ == "" {
+		typ = internal.TokenTypeBearer
+	}
+	req.Header.Set("Authorization", typ+" "+token.Value)
+}