Debugging Guide

January 30, 2026 · View on GitHub

Tips and techniques for debugging the Nylas CLI.

Quick Debugging

Enable Verbose Output

# Run command with verbose flag (if supported)
nylas --debug email list

# Check logs
tail -f ~/.config/nylas/nylas.log

Test API Directly

# Test authentication
curl -H "Authorization: Bearer YOUR_API_KEY" \
     https://api.nylas.com/v3/grants/YOUR_GRANT_ID

# Test specific endpoint
curl -H "Authorization: Bearer YOUR_API_KEY" \
     https://api.nylas.com/v3/grants/YOUR_GRANT_ID/messages?limit=1

Common Issues

"Command not found"

# Check installation
which nylas

# Verify PATH
echo $PATH

# Reinstall if needed
go install github.com/nylas/cli/cmd/nylas@latest

"401 Unauthorized"

# Check config
cat ~/.config/nylas/config.yaml

# Verify API key
nylas auth status

# Reconfigure
nylas auth config

"No such file or directory"

# Check file exists
ls -la /path/to/file

# Use absolute path
nylas email send --attach "/absolute/path/to/file.pdf"

Development Debugging

Using Delve Debugger

# Install Delve
go install github.com/go-delve/delve/cmd/dlv@latest

# Debug CLI
dlv debug github.com/nylas/cli/cmd/nylas -- email list

# Set breakpoint
(dlv) break main.main
(dlv) continue
(dlv) print variableName

import "fmt"

func myFunction() {
    // Add debug prints
    fmt.Printf("DEBUG: value = %+v\n", value)
    fmt.Printf("DEBUG: entering function with args: %v\n", args)
}

Logging

import "log"

log.Printf("Processing email: %s", emailID)
log.Printf("API response: %+v", response)

Testing Debugging

Run Single Test

# Run specific test
go test ./internal/cli/email/ -run TestSendEmail -v

# With race detector
go test -race ./internal/cli/email/ -run TestSendEmail

Debug Test

# Debug specific test
dlv test ./internal/cli/email/ -- -test.run TestSendEmail

func TestMyFunction(t *testing.T) {
    // Use t.Log instead of fmt.Print
    t.Logf("DEBUG: testing with value: %v", value)
    
    // Force test failure to see logs
    t.Errorf("Debug output: %+v", result)
}

Network Debugging

Capture HTTP Traffic

# Use mitmproxy
pip install mitmproxy
mitmproxy -p 8080

# Configure proxy
export HTTP_PROXY=http://localhost:8080
export HTTPS_PROXY=http://localhost:8080

# Run CLI
nylas email list

Check DNS

# Verify DNS resolution
nslookup api.nylas.com
dig api.nylas.com

# Test connectivity
ping api.nylas.com
curl -I https://api.nylas.com

Build Issues

Clean Build

# Remove artifacts
make clean

# Clear Go cache
go clean -cache -testcache -modcache

# Rebuild
make build

Dependency Issues

# Update dependencies
go mod tidy

# Verify go.mod
go mod verify

# Download dependencies
go mod download

IDE Debugging

VS Code

.vscode/launch.json:

{
    "version": "0.2.0",
    "configurations": [
        {
            "name": "Debug CLI",
            "type": "go",
            "request": "launch",
            "mode": "debug",
            "program": "${workspaceFolder}/cmd/nylas",
            "args": ["email", "list"],
            "env": {
                "NYLAS_API_KEY": "your-api-key",
                "NYLAS_GRANT_ID": "your-grant-id"
            }
        }
    ]
}

GoLand

  1. Run → Edit Configurations
  2. Add New Configuration → Go Build
  3. Set Program arguments: email list
  4. Set Environment variables: NYLAS_API_KEY=...
  5. Run → Debug

Performance Debugging

Profile CPU

# Run with CPU profiling
go test -cpuprofile=cpu.prof -bench=.

# Analyze profile
go tool pprof cpu.prof

Profile Memory

# Run with memory profiling
go test -memprofile=mem.prof -bench=.

# Analyze profile
go tool pprof mem.prof

Benchmark

func BenchmarkFunction(b *testing.B) {
    for i := 0; i < b.N; i++ {
        Function()
    }
}

Useful Commands

# Check Go environment
go env

# List dependencies
go list -m all

# Show module info
go list -m -json github.com/nylas/cli

# Find where CLI is installed
which nylas

# Check version
nylas version
go version

More Resources