Merge branch 'id-geo-http-push' into 'main'

Perform Git over HTTP request to primary repo

See merge request https://gitlab.com/gitlab-org/gitlab-shell/-/merge_requests/716

Merged-by: Ash McKenzie <amckenzie@gitlab.com>
Approved-by: Alejandro Rodríguez <alejandro@gitlab.com>
Approved-by: Ash McKenzie <amckenzie@gitlab.com>
Reviewed-by: Valery Sizov <valery@gitlab.com>
Reviewed-by: Alejandro Rodríguez <alejandro@gitlab.com>
Reviewed-by: Igor Drozdov <idrozdov@gitlab.com>
Reviewed-by: Ash McKenzie <amckenzie@gitlab.com>
Co-authored-by: Igor Drozdov <idrozdov@gitlab.com>

9 files changed, 431 insertions, 7 deletions

diff --git a/internal/command/githttp/push.go b/internal/command/githttp/push.go
new file mode 100644
index 0000000..3377baf
--- /dev/null
+++ b/internal/command/githttp/push.go
@@ -0,0 +1,106 @@
+package githttp
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/command/readwriter"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/config"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/gitlabnet/accessverifier"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/gitlabnet/git"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/pktline"
+)
+
+const service = "git-receive-pack"
+
+var receivePackHttpPrefix = []byte("001f# service=git-receive-pack\n0000")
+
+type PushCommand struct {
+	Config     *config.Config
+	ReadWriter *readwriter.ReadWriter
+	Response   *accessverifier.Response
+}
+
+// See Uploading Data > HTTP(S) section at:
+// https://git-scm.com/book/en/v2/Git-Internals-Transfer-Protocols
+//
+// 1. Perform /info/refs?service=git-receive-pack request
+// 2. Remove the header to make it consumable by SSH protocol
+// 3. Send the result to the user via SSH (writeToStdout)
+// 4. Read the send-pack data provided by user via SSH (stdinReader)
+// 5. Perform /git-receive-pack request and send this data
+// 6. Return the output to the user
+func (c *PushCommand) Execute(ctx context.Context) error {
+	data := c.Response.Payload.Data
+	client, err := git.NewClient(c.Config, data.PrimaryRepo, data.RequestHeaders)
+	if err != nil {
+		return err
+	}
+
+	if err := c.requestInfoRefs(ctx, client); err != nil {
+		return err
+	}
+
+	return c.requestReceivePack(ctx, client)
+}
+
+func (c *PushCommand) requestInfoRefs(ctx context.Context, client *git.Client) error {
+	response, err := client.InfoRefs(ctx, service)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+
+	// Read the first bytes that contain 001f# service=git-receive-pack\n0000 string
+	// to convert HTTP(S) Git response to the one expected by SSH
+	p := make([]byte, len(receivePackHttpPrefix))
+	_, err = response.Body.Read(p)
+	if err != nil || !bytes.Equal(p, receivePackHttpPrefix) {
+		return fmt.Errorf("Unexpected git-receive-pack response")
+	}
+
+	_, err = io.Copy(c.ReadWriter.Out, response.Body)
+
+	return err
+}
+
+func (c *PushCommand) requestReceivePack(ctx context.Context, client *git.Client) error {
+	pipeReader, pipeWriter := io.Pipe()
+	go c.readFromStdin(pipeWriter)
+
+	response, err := client.ReceivePack(ctx, pipeReader)
+	if err != nil {
+		return err
+	}
+	defer response.Body.Close()
+
+	_, err = io.Copy(c.ReadWriter.Out, response.Body)
+
+	return err
+}
+
+func (c *PushCommand) readFromStdin(pw *io.PipeWriter) {
+	var needsPackData bool
+
+	scanner := pktline.NewScanner(c.ReadWriter.In)
+	for scanner.Scan() {
+		line := scanner.Bytes()
+		pw.Write(line)
+
+		if pktline.IsFlush(line) {
+			break
+		}
+
+		if !needsPackData && !pktline.IsRefRemoval(line) {
+			needsPackData = true
+		}
+	}
+
+	if needsPackData {
+		io.Copy(pw, c.ReadWriter.In)
+	}
+
+	pw.Close()
+}
diff --git a/internal/command/githttp/push_test.go b/internal/command/githttp/push_test.go
new file mode 100644
index 0000000..1363abd
--- /dev/null
+++ b/internal/command/githttp/push_test.go
@@ -0,0 +1,150 @@
+package githttp
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"net/http"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"gitlab.com/gitlab-org/gitlab-shell/v14/client/testserver"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/command/readwriter"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/config"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/gitlabnet/accessverifier"
+)
+
+var (
+	flush                 = "0000"
+	infoRefsWithoutPrefix = "00c4e56497bb5f03a90a51293fc6d516788730953899 refs/heads/'test'report-status " +
+		"report-status-v2 delete-refs side-band-64k quiet atomic ofs-delta push-options object-format=sha1 " +
+		"agent=git/2.38.3.gl200\n" + flush
+)
+
+func TestExecute(t *testing.T) {
+	url, input := setup(t, http.StatusOK)
+	output := &bytes.Buffer{}
+
+	cmd := &PushCommand{
+		Config:     &config.Config{GitlabUrl: url},
+		ReadWriter: &readwriter.ReadWriter{Out: output, In: input},
+		Response: &accessverifier.Response{
+			Payload: accessverifier.CustomPayload{
+				Data: accessverifier.CustomPayloadData{PrimaryRepo: url},
+			},
+		},
+	}
+
+	require.NoError(t, cmd.Execute(context.Background()))
+	require.Equal(t, infoRefsWithoutPrefix, output.String())
+}
+
+func TestExecuteWithFailedInfoRefs(t *testing.T) {
+	testCases := []struct {
+		desc            string
+		statusCode      int
+		responseContent string
+		expectedErr     string
+	}{
+		{
+			desc:        "request failed",
+			statusCode:  http.StatusForbidden,
+			expectedErr: "Internal API error (403)",
+		}, {
+			desc:            "unexpected response",
+			statusCode:      http.StatusOK,
+			responseContent: "unexpected response",
+			expectedErr:     "Unexpected git-receive-pack response",
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.desc, func(t *testing.T) {
+			requests := []testserver.TestRequestHandler{
+				{
+					Path: "/info/refs",
+					Handler: func(w http.ResponseWriter, r *http.Request) {
+						require.Equal(t, "git-receive-pack", r.URL.Query().Get("service"))
+
+						w.WriteHeader(tc.statusCode)
+						w.Write([]byte(tc.responseContent))
+					},
+				},
+			}
+
+			url := testserver.StartHttpServer(t, requests)
+
+			cmd := &PushCommand{
+				Config: &config.Config{GitlabUrl: url},
+				Response: &accessverifier.Response{
+					Payload: accessverifier.CustomPayload{
+						Data: accessverifier.CustomPayloadData{PrimaryRepo: url},
+					},
+				},
+			}
+
+			err := cmd.Execute(context.Background())
+			require.Error(t, err)
+			require.Equal(t, tc.expectedErr, err.Error())
+		})
+	}
+}
+
+func TestExecuteWithFailedReceivePack(t *testing.T) {
+	url, input := setup(t, http.StatusForbidden)
+	output := &bytes.Buffer{}
+
+	cmd := &PushCommand{
+		Config:     &config.Config{GitlabUrl: url},
+		ReadWriter: &readwriter.ReadWriter{Out: output, In: input},
+		Response: &accessverifier.Response{
+			Payload: accessverifier.CustomPayload{
+				Data: accessverifier.CustomPayloadData{PrimaryRepo: url},
+			},
+		},
+	}
+
+	err := cmd.Execute(context.Background())
+	require.Error(t, err)
+	require.Equal(t, "Internal API error (403)", err.Error())
+}
+
+func setup(t *testing.T, receivePackStatusCode int) (string, io.Reader) {
+	infoRefs := "001f# service=git-receive-pack\n" + flush + infoRefsWithoutPrefix
+	receivePackPrefix := "00ab4c9d98d7750fa65db8ddcc60a89ef919f7a179f9 df505c066e4e63a801268a84627d7e8f7e033c7a " +
+		"refs/heads/main123 report-status-v2 side-band-64k object-format=sha1 agent=git/2.39.1"
+	receivePackData := "PACK some data"
+
+	// Imitate sending data via multiple packets
+	input := io.MultiReader(
+		strings.NewReader(receivePackPrefix),
+		strings.NewReader(flush),
+		strings.NewReader(receivePackData),
+	)
+
+	requests := []testserver.TestRequestHandler{
+		{
+			Path: "/info/refs",
+			Handler: func(w http.ResponseWriter, r *http.Request) {
+				require.Equal(t, "git-receive-pack", r.URL.Query().Get("service"))
+
+				w.Write([]byte(infoRefs))
+			},
+		},
+		{
+			Path: "/git-receive-pack",
+			Handler: func(w http.ResponseWriter, r *http.Request) {
+				body, err := io.ReadAll(r.Body)
+				require.NoError(t, err)
+				defer r.Body.Close()
+
+				require.Equal(t, receivePackPrefix+flush+receivePackData, string(body))
+				w.WriteHeader(receivePackStatusCode)
+			},
+		},
+	}
+
+	return testserver.StartHttpServer(t, requests), input
+}
diff --git a/internal/command/receivepack/receivepack.go b/internal/command/receivepack/receivepack.go
index 976ab39..c9ef7cd 100644
--- a/internal/command/receivepack/receivepack.go
+++ b/internal/command/receivepack/receivepack.go
@@ -4,6 +4,7 @@ import (
 	"context"
 
 	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/command/commandargs"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/command/githttp"
 	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/command/readwriter"
 	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/command/shared/accessverifier"
 	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/command/shared/customaction"
@@ -30,6 +31,20 @@ func (c *Command) Execute(ctx context.Context) error {
 	}
 
 	if response.IsCustomAction() {
+		// When `geo_proxy_direct_to_primary` feature flag is enabled, a Git over HTTP direct request
+		// to primary repo is performed instead of proxying the request through Gitlab Rails.
+		// After the feature flag is enabled by default and removed,
+		// custom action functionality will be removed along with it.
+		if response.Payload.Data.GeoProxyDirectToPrimary {
+			cmd := githttp.PushCommand{
+				Config:     c.Config,
+				ReadWriter: c.ReadWriter,
+				Response:   response,
+			}
+
+			return cmd.Execute(ctx)
+		}
+
 		customAction := customaction.Command{
 			Config:     c.Config,
 			ReadWriter: c.ReadWriter,
diff --git a/internal/command/shared/customaction/customaction.go b/internal/command/shared/customaction/customaction.go
index c12d685..e8b5ede 100644
--- a/internal/command/shared/customaction/customaction.go
+++ b/internal/command/shared/customaction/customaction.go
@@ -34,6 +34,9 @@ type Command struct {
 	EOFSent    bool
 }
 
+// When `geo_proxy_direct_to_primary` feature flag is enabled, a Git over HTTP direct request
+// to primary repo is performed instead of proxying the request through Gitlab Rails.
+// After the feature flag is enabled by default and removed, this package will be removed along with it.
 func (c *Command) Execute(ctx context.Context, response *accessverifier.Response) error {
 	data := response.Payload.Data
 	apiEndpoints := data.ApiEndpoints
diff --git a/internal/gitlabnet/accessverifier/client.go b/internal/gitlabnet/accessverifier/client.go
index 8554d9b..b2383dc 100644
--- a/internal/gitlabnet/accessverifier/client.go
+++ b/internal/gitlabnet/accessverifier/client.go
@@ -40,10 +40,12 @@ type Gitaly struct {
 }
 
 type CustomPayloadData struct {
-	ApiEndpoints []string `json:"api_endpoints"`
-	Username     string   `json:"gl_username"`
-	PrimaryRepo  string   `json:"primary_repo"`
-	UserId       string   `json:"gl_id,omitempty"`
+	ApiEndpoints            []string          `json:"api_endpoints"`
+	Username                string            `json:"gl_username"`
+	PrimaryRepo             string            `json:"primary_repo"`
+	UserId                  string            `json:"gl_id,omitempty"`
+	RequestHeaders          map[string]string `json:"request_headers"`
+	GeoProxyDirectToPrimary bool              `json:"geo_proxy_direct_to_primary"`
 }
 
 type CustomPayload struct {
diff --git a/internal/gitlabnet/accessverifier/client_test.go b/internal/gitlabnet/accessverifier/client_test.go
index f2c88a5..e203200 100644
--- a/internal/gitlabnet/accessverifier/client_test.go
+++ b/internal/gitlabnet/accessverifier/client_test.go
@@ -107,9 +107,11 @@ func TestGeoPushGetCustomAction(t *testing.T) {
 	response.Payload = CustomPayload{
 		Action: "geo_proxy_to_primary",
 		Data: CustomPayloadData{
-			ApiEndpoints: []string{"geo/proxy_git_ssh/info_refs_receive_pack", "geo/proxy_git_ssh/receive_pack"},
-			Username:     "custom",
-			PrimaryRepo:  "https://repo/path",
+			ApiEndpoints:            []string{"geo/proxy_git_ssh/info_refs_receive_pack", "geo/proxy_git_ssh/receive_pack"},
+			GeoProxyDirectToPrimary: true,
+			RequestHeaders:          map[string]string{"Authorization": "Bearer token"},
+			Username:                "custom",
+			PrimaryRepo:             "https://repo/path",
 		},
 	}
 	response.StatusCode = 300
diff --git a/internal/gitlabnet/git/client.go b/internal/gitlabnet/git/client.go
new file mode 100644
index 0000000..db71e3f
--- /dev/null
+++ b/internal/gitlabnet/git/client.go
@@ -0,0 +1,56 @@
+package git
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net/http"
+
+	"gitlab.com/gitlab-org/gitlab-shell/v14/client"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/config"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/gitlabnet"
+)
+
+type Client struct {
+	url     string
+	headers map[string]string
+	client  *client.GitlabNetClient
+}
+
+func NewClient(cfg *config.Config, url string, headers map[string]string) (*Client, error) {
+	client, err := gitlabnet.GetClient(cfg)
+	if err != nil {
+		return nil, fmt.Errorf("Error creating http client: %v", err)
+	}
+
+	return &Client{client: client, headers: headers, url: url}, nil
+}
+
+func (c *Client) InfoRefs(ctx context.Context, service string) (*http.Response, error) {
+	request, err := http.NewRequestWithContext(ctx, http.MethodGet, c.url+"/info/refs?service="+service, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return c.do(request)
+}
+
+func (c *Client) ReceivePack(ctx context.Context, body io.Reader) (*http.Response, error) {
+	request, err := http.NewRequestWithContext(ctx, http.MethodPost, c.url+"/git-receive-pack", body)
+	if err != nil {
+		return nil, err
+	}
+	request.Header.Add("Content-Type", "application/x-git-receive-pack-request")
+	request.Header.Add("Accept", "application/x-git-receive-pack-result")
+
+	return c.do(request)
+}
+
+func (c *Client) do(request *http.Request) (*http.Response, error) {
+
+	for k, v := range c.headers {
+		request.Header.Add(k, v)
+	}
+
+	return c.client.Do(request)
+}
diff --git a/internal/gitlabnet/git/client_test.go b/internal/gitlabnet/git/client_test.go
new file mode 100644
index 0000000..b550e99
--- /dev/null
+++ b/internal/gitlabnet/git/client_test.go
@@ -0,0 +1,88 @@
+package git
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"net/http"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/client/testserver"
+	"gitlab.com/gitlab-org/gitlab-shell/v14/internal/config"
+)
+
+var customHeaders = map[string]string{
+	"Authorization": "Bearer: token",
+	"Header-One":    "Value-Two",
+}
+
+func TestInfoRefs(t *testing.T) {
+	client := setup(t)
+
+	for _, service := range []string{
+		"git-receive-pack",
+		"git-upload-pack",
+		"git-archive-pack",
+	} {
+		response, err := client.InfoRefs(context.Background(), service)
+		require.NoError(t, err)
+
+		body, err := io.ReadAll(response.Body)
+		require.NoError(t, err)
+		defer response.Body.Close()
+
+		require.Equal(t, service, string(body))
+	}
+}
+
+func TestReceivePack(t *testing.T) {
+	client := setup(t)
+
+	content := "content"
+	response, err := client.ReceivePack(context.Background(), bytes.NewReader([]byte(content)))
+	require.NoError(t, err)
+	defer response.Body.Close()
+
+	body, err := io.ReadAll(response.Body)
+	require.NoError(t, err)
+
+	require.Equal(t, "git-receive-pack: content", string(body))
+}
+
+func setup(t *testing.T) *Client {
+	requests := []testserver.TestRequestHandler{
+		{
+			Path: "/info/refs",
+			Handler: func(w http.ResponseWriter, r *http.Request) {
+				require.Equal(t, customHeaders["Authorization"], r.Header.Get("Authorization"))
+				require.Equal(t, customHeaders["Header-One"], r.Header.Get("Header-One"))
+
+				w.Write([]byte(r.URL.Query().Get("service")))
+			},
+		},
+		{
+			Path: "/git-receive-pack",
+			Handler: func(w http.ResponseWriter, r *http.Request) {
+				require.Equal(t, customHeaders["Authorization"], r.Header.Get("Authorization"))
+				require.Equal(t, customHeaders["Header-One"], r.Header.Get("Header-One"))
+				require.Equal(t, "application/x-git-receive-pack-request", r.Header.Get("Content-Type"))
+				require.Equal(t, "application/x-git-receive-pack-result", r.Header.Get("Accept"))
+				require.Equal(t, customHeaders["Header-One"], r.Header.Get("Header-One"))
+
+				body, err := io.ReadAll(r.Body)
+				require.NoError(t, err)
+				defer r.Body.Close()
+
+				w.Write([]byte("git-receive-pack: "))
+				w.Write(body)
+			},
+		},
+	}
+
+	url := testserver.StartHttpServer(t, requests)
+	client, err := NewClient(&config.Config{GitlabUrl: url}, url, customHeaders)
+	require.NoError(t, err)
+
+	return client
+}
diff --git a/internal/testhelper/testdata/testroot/responses/allowed_with_push_payload.json b/internal/testhelper/testdata/testroot/responses/allowed_with_push_payload.json
index 318d42d..adedda4 100644
--- a/internal/testhelper/testdata/testroot/responses/allowed_with_push_payload.json
+++ b/internal/testhelper/testdata/testroot/responses/allowed_with_push_payload.json
@@ -21,6 +21,8 @@
     "action": "geo_proxy_to_primary",
 		"data": {
 			"api_endpoints": ["geo/proxy_git_ssh/info_refs_receive_pack", "geo/proxy_git_ssh/receive_pack"],
+			"geo_proxy_direct_to_primary": true,
+			"request_headers": { "Authorization": "Bearer token" },
 			"gl_username":   "custom",
 			"primary_repo":  "https://repo/path"
     }