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Merged
merged 2 commits into from
May 7, 2025
Merged

Support debugging e2e tests #380

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db8a6c4
Extract ghmcp internal package
williammartin May 7, 2025
bd1df79
Support breakpoint debugging e2e tests
williammartin May 7, 2025
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188 changes: 22 additions & 166 deletions cmd/github-mcp-server/main.go
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Original file line number Diff line number Diff line change
@@ -1,25 +1,17 @@
package main

import (
"context"
"errors"
"fmt"
"io"
stdlog "log"
"os"
"os/signal"
"syscall"

"github.com/github/github-mcp-server/internal/ghmcp"
"github.com/github/github-mcp-server/pkg/github"
iolog "github.com/github/github-mcp-server/pkg/log"
"github.com/github/github-mcp-server/pkg/translations"
gogithub "github.com/google/go-github/v69/github"
"github.com/mark3labs/mcp-go/mcp"
"github.com/mark3labs/mcp-go/server"
log "github.com/sirupsen/logrus"
"github.com/spf13/cobra"
"github.com/spf13/viper"
)

// These variables are set by the build process using ldflags.
var version = "version"
var commit = "commit"
var date = "date"
Expand All @@ -36,36 +28,34 @@ var (
Use: "stdio",
Short: "Start stdio server",
Long: `Start a server that communicates via standard input/output streams using JSON-RPC messages.`,
Run: func(_ *cobra.Command, _ []string) {
logFile := viper.GetString("log-file")
readOnly := viper.GetBool("read-only")
exportTranslations := viper.GetBool("export-translations")
logger, err := initLogger(logFile)
if err != nil {
stdlog.Fatal("Failed to initialize logger:", err)
RunE: func(_ *cobra.Command, _ []string) error {
token := viper.GetString("personal_access_token")
if token == "" {
return errors.New("GITHUB_PERSONAL_ACCESS_TOKEN not set")
}

// If you're wondering why we're not using viper.GetStringSlice("toolsets"),
// it's because viper doesn't handle comma-separated values correctly for env
// vars when using GetStringSlice.
// https://github.com/spf13/viper/issues/380
var enabledToolsets []string
err = viper.UnmarshalKey("toolsets", &enabledToolsets)
if err != nil {
stdlog.Fatal("Failed to unmarshal toolsets:", err)
if err := viper.UnmarshalKey("toolsets", &enabledToolsets); err != nil {
return fmt.Errorf("failed to unmarshal toolsets: %w", err)
}

logCommands := viper.GetBool("enable-command-logging")
cfg := runConfig{
readOnly: readOnly,
logger: logger,
logCommands: logCommands,
exportTranslations: exportTranslations,
enabledToolsets: enabledToolsets,
}
if err := runStdioServer(cfg); err != nil {
stdlog.Fatal("failed to run stdio server:", err)
stdioServerConfig := ghmcp.StdioServerConfig{
Version: version,
Host: viper.GetString("host"),
Token: token,
EnabledToolsets: enabledToolsets,
DynamicToolsets: viper.GetBool("dynamic_toolsets"),
ReadOnly: viper.GetBool("read-only"),
ExportTranslations: viper.GetBool("export-translations"),
EnableCommandLogging: viper.GetBool("enable-command-logging"),
LogFilePath: viper.GetString("log-file"),
}

return ghmcp.RunStdioServer(stdioServerConfig)
},
}
)
Expand Down Expand Up @@ -103,143 +93,9 @@ func initConfig() {
viper.AutomaticEnv()
}

func initLogger(outPath string) (*log.Logger, error) {
if outPath == "" {
return log.New(), nil
}

file, err := os.OpenFile(outPath, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0666)
if err != nil {
return nil, fmt.Errorf("failed to open log file: %w", err)
}

logger := log.New()
logger.SetLevel(log.DebugLevel)
logger.SetOutput(file)

return logger, nil
}

type runConfig struct {
readOnly bool
logger *log.Logger
logCommands bool
exportTranslations bool
enabledToolsets []string
}

func runStdioServer(cfg runConfig) error {
// Create app context
ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
defer stop()

// Create GH client
token := viper.GetString("personal_access_token")
if token == "" {
cfg.logger.Fatal("GITHUB_PERSONAL_ACCESS_TOKEN not set")
}
ghClient := gogithub.NewClient(nil).WithAuthToken(token)
ghClient.UserAgent = fmt.Sprintf("github-mcp-server/%s", version)

host := viper.GetString("host")

if host != "" {
var err error
ghClient, err = ghClient.WithEnterpriseURLs(host, host)
if err != nil {
return fmt.Errorf("failed to create GitHub client with host: %w", err)
}
}

t, dumpTranslations := translations.TranslationHelper()

beforeInit := func(_ context.Context, _ any, message *mcp.InitializeRequest) {
ghClient.UserAgent = fmt.Sprintf("github-mcp-server/%s (%s/%s)", version, message.Params.ClientInfo.Name, message.Params.ClientInfo.Version)
}

getClient := func(_ context.Context) (*gogithub.Client, error) {
return ghClient, nil // closing over client
}

hooks := &server.Hooks{
OnBeforeInitialize: []server.OnBeforeInitializeFunc{beforeInit},
}
// Create server
ghServer := github.NewServer(version, server.WithHooks(hooks))

enabled := cfg.enabledToolsets
dynamic := viper.GetBool("dynamic_toolsets")
if dynamic {
// filter "all" from the enabled toolsets
enabled = make([]string, 0, len(cfg.enabledToolsets))
for _, toolset := range cfg.enabledToolsets {
if toolset != "all" {
enabled = append(enabled, toolset)
}
}
}

// Create default toolsets
toolsets, err := github.InitToolsets(enabled, cfg.readOnly, getClient, t)
context := github.InitContextToolset(getClient, t)

if err != nil {
stdlog.Fatal("Failed to initialize toolsets:", err)
}

// Register resources with the server
github.RegisterResources(ghServer, getClient, t)
// Register the tools with the server
toolsets.RegisterTools(ghServer)
context.RegisterTools(ghServer)

if dynamic {
dynamic := github.InitDynamicToolset(ghServer, toolsets, t)
dynamic.RegisterTools(ghServer)
}

stdioServer := server.NewStdioServer(ghServer)

stdLogger := stdlog.New(cfg.logger.Writer(), "stdioserver", 0)
stdioServer.SetErrorLogger(stdLogger)

if cfg.exportTranslations {
// Once server is initialized, all translations are loaded
dumpTranslations()
}

// Start listening for messages
errC := make(chan error, 1)
go func() {
in, out := io.Reader(os.Stdin), io.Writer(os.Stdout)

if cfg.logCommands {
loggedIO := iolog.NewIOLogger(in, out, cfg.logger)
in, out = loggedIO, loggedIO
}

errC <- stdioServer.Listen(ctx, in, out)
}()

// Output github-mcp-server string
_, _ = fmt.Fprintf(os.Stderr, "GitHub MCP Server running on stdio\n")

// Wait for shutdown signal
select {
case <-ctx.Done():
cfg.logger.Infof("shutting down server...")
case err := <-errC:
if err != nil {
return fmt.Errorf("error running server: %w", err)
}
}

return nil
}

func main() {
if err := rootCmd.Execute(); err != nil {
fmt.Println(err)
fmt.Fprintf(os.Stderr, "%v\n", err)
os.Exit(1)
}
}
6 changes: 6 additions & 0 deletions e2e/README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,12 @@ FAIL github.com/github/github-mcp-server/e2e 1.433s
FAIL
```

## Debugging the Tests

It is possible to provide `GITHUB_MCP_SERVER_E2E_DEBUG=true` to run the e2e tests with an in-process version of the MCP server. This has slightly reduced coverage as it doesn't integrate with Docker, or make use of the cobra/viper configuration parsing. However, it allows for placing breakpoints in the MCP Server internals, supporting much better debugging flows than the fully black-box tests.

One might argue that the lack of visibility into failures for the black box tests also indicates a product need, but this solves for the immediate pain point felt as a maintainer.

## Limitations

The current test suite is intentionally very limited in scope. This is because the maintenance costs on e2e tests tend to increase significantly over time. To read about some challenges with GitHub integration tests, see [go-github integration tests README](https://github.com/google/go-github/blob/5b75aa86dba5cf4af2923afa0938774f37fa0a67/test/README.md). We will expand this suite circumspectly!
Expand Down
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