cli: add --debug-http flag (#7192)

This makes it easier to help debug client issues.

cli/root.go

@@ -364,6 +364,13 @@ func (r *RootCmd) Command(subcommands []*clibase.Cmd) (*clibase.Cmd, error) {
 			Value:         clibase.BoolOf(&r.verbose),
 			Group:         globalGroup,
 		},
+		{
+			Flag:        "debug-http",
+			Description: "Debug codersdk HTTP requests.",
+			Value:       clibase.BoolOf(&r.debugHTTP),
+			Group:       globalGroup,
+			Hidden:      true,
+		},
 		{
 			Flag:        config.FlagName,
 			Env:         "CODER_CONFIG_DIR",
@@ -412,6 +419,7 @@ type RootCmd struct {
 	forceTTY     bool
 	noOpen       bool
 	verbose      bool
+	debugHTTP    bool
 
 	noVersionCheck   bool
 	noFeatureWarning bool
@@ -464,6 +472,11 @@ func (r *RootCmd) InitClient(client *codersdk.Client) clibase.MiddlewareFunc {
 
 			client.SetSessionToken(r.token)
 
+			if r.debugHTTP {
+				client.PlainLogger = os.Stderr
+				client.LogBodies = true
+			}
+
 			// We send these requests in parallel to minimize latency.
 			var (
 				versionErr = make(chan error)

codersdk/client.go

@@ -10,6 +10,7 @@ import (
 	"mime"
 	"net"
 	"net/http"
+	"net/http/httputil"
 	"net/url"
 	"strings"
 	"sync"
@@ -90,6 +91,10 @@ type Client struct {
 	// LogBodies can be enabled to print request and response bodies to the logger.
 	LogBodies bool
 
+	// PlainLogger may be set to log HTTP traffic in a human-readable form.
+	// It uses the LogBodies option.
+	PlainLogger io.Writer
+
 	// Trace can be enabled to propagate tracing spans to the Coder API.
 	// This is useful for tracking a request end-to-end.
 	Trace bool
@@ -109,6 +114,16 @@ func (c *Client) SetSessionToken(token string) {
 	c.sessionToken = token
 }
 
+func prefixLines(prefix, s []byte) []byte {
+	ss := bytes.NewBuffer(make([]byte, 0, len(s)*2))
+	for _, line := range bytes.Split(s, []byte("\n")) {
+		_, _ = ss.Write(prefix)
+		_, _ = ss.Write(line)
+		_ = ss.WriteByte('\n')
+	}
+	return ss.Bytes()
+}
+
 // Request performs a HTTP request with the body provided. The caller is
 // responsible for closing the response body.
 func (c *Client) Request(ctx context.Context, method, path string, body interface{}, opts ...RequestOption) (*http.Response, error) {
@@ -155,6 +170,15 @@ func (c *Client) Request(ctx context.Context, method, path string, body interfac
 		return nil, xerrors.Errorf("create request: %w", err)
 	}
 
+	if c.PlainLogger != nil {
+		out, err := httputil.DumpRequest(req, c.LogBodies)
+		if err != nil {
+			return nil, xerrors.Errorf("dump request: %w", err)
+		}
+		out = prefixLines([]byte("http --> "), out)
+		_, _ = c.PlainLogger.Write(out)
+	}
+
 	tokenHeader := c.SessionTokenHeader
 	if tokenHeader == "" {
 		tokenHeader = SessionTokenHeader
@@ -192,6 +216,15 @@ func (c *Client) Request(ctx context.Context, method, path string, body interfac
 		return nil, err
 	}
 
+	if c.PlainLogger != nil {
+		out, err := httputil.DumpResponse(resp, c.LogBodies)
+		if err != nil {
+			return nil, xerrors.Errorf("dump response: %w", err)
+		}
+		out = prefixLines([]byte("http <-- "), out)
+		_, _ = c.PlainLogger.Write(out)
+	}
+
 	span.SetAttributes(httpconv.ClientResponse(resp)...)
 	span.SetStatus(httpconv.ClientStatus(resp.StatusCode))