cli/internal/codespaces/grpc/client.go
2022-09-30 11:55:57 -07:00

130 lines
3.9 KiB
Go

package grpc
// gRPC client implementation to be able to connect to the gRPC server and perform the following operations:
// - Start a remote JupyterLab server
import (
"context"
"fmt"
"net"
"strconv"
"time"
"github.com/cli/cli/v2/internal/codespaces/grpc/jupyter"
"github.com/cli/cli/v2/pkg/liveshare"
"golang.org/x/crypto/ssh"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials/insecure"
"google.golang.org/grpc/metadata"
)
const (
connectionTimeout = 5 * time.Second
requestTimeout = 30 * time.Second
)
const (
codespacesInternalPort = 16634
codespacesInternalSessionName = "CodespacesInternal"
)
type Client struct {
conn *grpc.ClientConn
token string
listener net.Listener
jupyterClient jupyter.JupyterServerHostClient
}
type liveshareSession interface {
KeepAlive(string)
OpenStreamingChannel(context.Context, liveshare.ChannelID) (ssh.Channel, error)
StartSharing(context.Context, string, int) (liveshare.ChannelID, error)
}
// Finds a free port to listen on and creates a new gRPC client that connects to that port
func Connect(ctx context.Context, session liveshareSession, token string) (*Client, error) {
listener, err := net.Listen("tcp", fmt.Sprintf("127.0.0.1:%d", 0))
if err != nil {
return nil, fmt.Errorf("failed to listen to local port over tcp: %w", err)
}
// Tunnel the remote gRPC server port to the local port
localPort := listener.Addr().(*net.TCPAddr).Port
internalTunnelClosed := make(chan error, 1)
go func() {
fwd := liveshare.NewPortForwarder(session, codespacesInternalSessionName, codespacesInternalPort, true)
internalTunnelClosed <- fwd.ForwardToListener(ctx, listener)
}()
// Create the gRPC client
client, err := NewClient(ctx, session, token, localPort)
if err != nil {
return nil, fmt.Errorf("failed to create client: %w", err)
}
// Attach the listener so we can close it later
client.listener = listener
return client, err
}
// Creates a new gRPC client that connects to the given port
func NewClient(ctx context.Context, session liveshareSession, token string, localPort int) (*Client, error) {
// Attempt to connect to the given port
opts := []grpc.DialOption{
grpc.WithTransportCredentials(insecure.NewCredentials()),
grpc.WithBlock(),
}
ctx, _ = context.WithTimeout(ctx, connectionTimeout)
conn, err := grpc.DialContext(ctx, fmt.Sprintf("127.0.0.1:%d", localPort), opts...)
if err != nil {
return nil, err
}
g := &Client{
conn: conn,
token: token,
jupyterClient: jupyter.NewJupyterServerHostClient(conn),
}
return g, nil
}
// Closes the gRPC connection
func (g *Client) Close() error {
// Closing the local listener effectively closes the gRPC connection
if err := g.listener.Close(); err != nil {
g.conn.Close() // If we fail to close the listener, explicitly close the gRPC connection and ignore any error
return fmt.Errorf("failed to close local tcp port listener: %w", err)
}
return nil
}
// Appends the authentication token to the gRPC context
func (g *Client) appendMetadata(ctx context.Context) context.Context {
return metadata.AppendToOutgoingContext(ctx, "Authorization", "Bearer "+g.token)
}
// Starts a remote JupyterLab server to allow the user to connect to the codespace via JupyterLab in their browser
func (g *Client) StartJupyterServer(ctx context.Context) (port int, serverUrl string, err error) {
ctx, cancel := context.WithTimeout(ctx, requestTimeout)
ctx = g.appendMetadata(ctx)
defer cancel()
response, err := g.jupyterClient.GetRunningServer(ctx, &jupyter.GetRunningServerRequest{})
if err != nil {
return 0, "", fmt.Errorf("failed to invoke JupyterLab RPC: %w", err)
}
if !response.Result {
return 0, "", fmt.Errorf("failed to start JupyterLab: %s", response.Message)
}
port, err = strconv.Atoi(response.Port)
if err != nil {
return 0, "", fmt.Errorf("failed to parse JupyterLab port: %w", err)
}
return port, response.ServerUrl, err
}