mirror of https://github.com/harivansh-afk/sandbox-agent.git synced 2026-04-15 14:03:52 +00:00

i need to update the terminology of 'capabilities' to 'feature coverage' in the inspector ui and anywhere else its mentioned thats not in the actual api (#61 )

2026-02-02 19:00:35 -08:00

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Detecting cloud sandbox providers from within your code

A process can reliably identify its sandbox provider by checking environment variables, filesystem markers, and metadata endpoints in a specific order. Environment variables are the fastest and most reliable method for most sandbox providers, with each major provider exposing unique prefixed variables like E2B_SANDBOX, VERCEL, FLY_APP_NAME, and REPL_ID. This report provides a complete detection strategy with tested code examples for implementing provider telemetry.

The detection hierarchy should be: environment variables first (instant), filesystem checks second (sub-millisecond), and metadata services last (100-500ms with network calls). Most sandbox providers now expose explicit environment variables specifically designed for runtime detection, making identification straightforward when you know what to look for.

E2B sandboxes expose four dedicated environment variables

E2B provides the cleanest detection story with explicitly documented environment variables and filesystem fallbacks:

Variable	Value/Example	Confidence
`E2B_SANDBOX`	`"true"`	✅ Documented
`E2B_SANDBOX_ID`	Unique sandbox identifier	✅ Documented
`E2B_TEAM_ID`	Team that created the sandbox	✅ Documented
`E2B_TEMPLATE_ID`	Template used for sandbox	✅ Documented

Filesystem fallback: When using E2B CLI (not SDK), these values are also stored as dot files at /run/e2b/.E2B_SANDBOX, /run/e2b/.E2B_SANDBOX_ID, etc.

function detectE2B(): ProviderResult | null {
  if (process.env.E2B_SANDBOX === 'true') {
    return {
      provider: 'e2b',
      confidence: 'high',
      metadata: {
        sandboxId: process.env.E2B_SANDBOX_ID,
        teamId: process.env.E2B_TEAM_ID,
        templateId: process.env.E2B_TEMPLATE_ID,
      }
    };
  }
  
  // Filesystem fallback for CLI usage
  if (fs.existsSync('/run/e2b/.E2B_SANDBOX')) {
    return { provider: 'e2b', confidence: 'high', method: 'filesystem' };
  }
  return null;
}

Daytona requires heuristic detection through user and directory checks

Daytona lacks explicit detection environment variables, requiring multiple signal checks:

Detection Method	Marker	Confidence
Username	Running as user `daytona`	⚠️ Medium
Home directory	`/home/daytona` exists	⚠️ Medium
Config directory	`~/.daytona` exists	⚠️ Medium
Container image	`daytonaio/workspace-project`	⚠️ Medium

function detectDaytona(): ProviderResult | null {
  const signals: string[] = [];
  
  // Check username
  const username = os.userInfo().username;
  if (username === 'daytona') signals.push('user');
  
  // Check home directory
  if (fs.existsSync('/home/daytona')) signals.push('home_dir');
  
  // Check config directory
  const configPath = path.join(os.homedir(), '.daytona');
  if (fs.existsSync(configPath)) signals.push('config_dir');
  
  if (signals.length >= 2) {
    return { provider: 'daytona', confidence: 'medium', signals };
  }
  return null;
}

Recommendation: File a feature request with Daytona to add DAYTONA_SANDBOX=true for reliable detection.

Vercel detection varies by runtime type

Vercel environments are more complex because they span serverless functions (AWS Lambda), Edge Runtime (V8), and the newer Sandbox SDK:

Core detection variables (available in all Vercel environments):

Variable	Description
`VERCEL`	`"1"` — Primary indicator
`VERCEL_ENV`	`production`, `preview`, or `development`
`VERCEL_REGION`	Region code like `cdg1`, `iad1` (runtime only)
`VERCEL_DEPLOYMENT_ID`	Unique deployment identifier
`VERCEL_URL`	Deployment URL without protocol

Runtime-specific detection:

function detectVercel(): VercelEnvironment | null {
  if (process.env.VERCEL !== '1') return null;
  
  const isEdgeRuntime = typeof globalThis.EdgeRuntime !== 'undefined';
  const isServerless = Boolean(process.env.LAMBDA_TASK_ROOT);
  const isBuildTime = process.env.CI === '1';
  
  let runtimeType: 'edge' | 'serverless' | 'static' | 'sandbox';
  if (isEdgeRuntime) runtimeType = 'edge';
  else if (isServerless) runtimeType = 'serverless';
  else if (process.env.VERCEL_SANDBOX) runtimeType = 'sandbox';
  else runtimeType = 'static';
  
  return {
    provider: 'vercel',
    confidence: 'high',
    runtimeType,
    environment: process.env.VERCEL_ENV as 'production' | 'preview' | 'development',
    region: process.env.VERCEL_REGION,
    deploymentId: process.env.VERCEL_DEPLOYMENT_ID,
  };
}

Lambda indicators (underneath Vercel serverless): LAMBDA_TASK_ROOT, AWS_LAMBDA_FUNCTION_NAME, AWS_REGION, AWS_EXECUTION_ENV.

Request header detection for runtime context: x-vercel-id (trace ID with region), x-vercel-deployment-url, x-vercel-ip-country.

CodeSandbox and Replit detection through environment and filesystem

CodeSandbox uses CODESANDBOX_HOST as the primary indicator:

function detectCodeSandbox(): ProviderResult | null {
  if (process.env.CODESANDBOX_HOST || process.env.CSB_BASE_PREVIEW_HOST) {
    return {
      provider: 'codesandbox',
      confidence: 'high',
      host: process.env.CODESANDBOX_HOST,
    };
  }
  // Legacy SSE sandboxes
  if (process.env.CODESANDBOX_SSE || process.env.SANDBOX_URL) {
    return { provider: 'codesandbox', confidence: 'high', legacy: true };
  }
  return null;
}

Replit exposes comprehensive environment variables:

Variable	Description
`REPL_ID`	Unique repl identifier
`REPL_SLUG`	URL-safe repl name
`REPL_OWNER`	Username of owner
`REPLIT_DB_URL`	Built-in database URL

function detectReplit(): ProviderResult | null {
  if (process.env.REPL_ID || process.env.REPL_SLUG) {
    return {
      provider: 'replit',
      confidence: 'high',
      replId: process.env.REPL_ID,
      slug: process.env.REPL_SLUG,
      owner: process.env.REPL_OWNER,
    };
  }
  // Filesystem fallback
  if (fs.existsSync('.replit') || fs.existsSync('replit.nix')) {
    return { provider: 'replit', confidence: 'medium', method: 'filesystem' };
  }
  return null;
}

Modal provides reserved environment variables that cannot be overridden:

Variable	Scope
`MODAL_IS_REMOTE`	`"1"` when in Modal container
`MODAL_CLOUD_PROVIDER`	AWS, GCP, or OCI
`MODAL_REGION`	Geographic region
`MODAL_TASK_ID`	Container ID
`MODAL_SANDBOX_ID`	Sandbox-only identifier
`MODAL_ENVIRONMENT`	Functions-only environment name

function detectModal(): ProviderResult | null {
  if (process.env.MODAL_IS_REMOTE === '1' || process.env.MODAL_CLOUD_PROVIDER) {
    const isSandbox = Boolean(process.env.MODAL_SANDBOX_ID);
    return {
      provider: 'modal',
      confidence: 'high',
      type: isSandbox ? 'sandbox' : 'function',
      cloudProvider: process.env.MODAL_CLOUD_PROVIDER,
      region: process.env.MODAL_REGION,
      taskId: process.env.MODAL_TASK_ID,
    };
  }
  return null;
}

Fly.io similarly exposes comprehensive runtime variables:

Variable	Description
`FLY_APP_NAME`	Application name
`FLY_MACHINE_ID`	Unique machine ID
`FLY_REGION`	Three-letter region code (`ams`, `ord`)
`FLY_VM_MEMORY_MB`	Allocated memory
`PRIMARY_REGION`	Primary deployment region

function detectFlyIo(): ProviderResult | null {
  if (process.env.FLY_APP_NAME || process.env.FLY_MACHINE_ID) {
    return {
      provider: 'fly.io',
      confidence: 'high',
      appName: process.env.FLY_APP_NAME,
      machineId: process.env.FLY_MACHINE_ID,
      region: process.env.FLY_REGION,
      memoryMb: process.env.FLY_VM_MEMORY_MB,
    };
  }
  return null;
}

General detection techniques for unknown providers

When dedicated environment variables aren't available, use these hierarchical fallbacks:

Container detection via cgroups and filesystem:

function detectContainer(): ContainerInfo | null {
  // Docker
  if (fs.existsSync('/.dockerenv')) {
    return { type: 'docker', confidence: 'high' };
  }
  
  // Podman
  if (fs.existsSync('/run/.containerenv')) {
    return { type: 'podman', confidence: 'high' };
  }
  
  // Kubernetes
  if (process.env.KUBERNETES_SERVICE_HOST) {
    return { 
      type: 'kubernetes', 
      confidence: 'high',
      namespace: fs.readFileSync(
        '/var/run/secrets/kubernetes.io/serviceaccount/namespace', 'utf8'
      ).trim()
    };
  }
  
  // Cgroup inspection for containerized environments
  try {
    const cgroup = fs.readFileSync('/proc/1/cgroup', 'utf8');
    if (cgroup.includes('docker') || cgroup.includes('containerd')) {
      return { type: 'docker', confidence: 'medium', method: 'cgroup' };
    }
    if (cgroup.includes('kubepods')) {
      return { type: 'kubernetes', confidence: 'medium', method: 'cgroup' };
    }
  } catch {}
  
  return null;
}

VM/Hypervisor detection via DMI data:

function detectHypervisor(): HypervisorInfo | null {
  const dmiPaths = {
    sysVendor: '/sys/class/dmi/id/sys_vendor',
    productName: '/sys/class/dmi/id/product_name',
    biosVendor: '/sys/class/dmi/id/bios_vendor',
  };
  
  const vendorMappings: Record<string, string> = {
    'Amazon EC2': 'aws',
    'Google Compute Engine': 'gcp',
    'Microsoft Corporation': 'azure',
    'VMware, Inc.': 'vmware',
    'QEMU': 'qemu',
    'Xen': 'xen',
    'innotek GmbH': 'virtualbox',
  };
  
  try {
    const sysVendor = fs.readFileSync(dmiPaths.sysVendor, 'utf8').trim();
    const productName = fs.readFileSync(dmiPaths.productName, 'utf8').trim();
    
    for (const [pattern, provider] of Object.entries(vendorMappings)) {
      if (sysVendor.includes(pattern) || productName.includes(pattern)) {
        return { hypervisor: provider, sysVendor, productName };
      }
    }
  } catch {}
  
  return null;
}

Cloud metadata service for major cloud providers:

async function detectCloudViaMetadata(timeoutMs = 500): Promise<CloudInfo | null> {
  const endpoints = [
    { provider: 'aws', url: 'http://169.254.169.254/latest/meta-data/', headers: {} },
    { provider: 'gcp', url: 'http://169.254.169.254/computeMetadata/v1/', 
      headers: { 'Metadata-Flavor': 'Google' } },
    { provider: 'azure', url: 'http://169.254.169.254/metadata/instance?api-version=2021-02-01',
      headers: { 'Metadata': 'true' } },
  ];
  
  const controller = new AbortController();
  const timeout = setTimeout(() => controller.abort(), timeoutMs);
  
  try {
    const results = await Promise.allSettled(
      endpoints.map(async ({ provider, url, headers }) => {
        const res = await fetch(url, { 
          headers, 
          signal: controller.signal 
        });
        if (res.ok) return provider;
        throw new Error('Not this provider');
      })
    );
    
    for (const result of results) {
      if (result.status === 'fulfilled') {
        return { provider: result.value, method: 'metadata' };
      }
    }
  } finally {
    clearTimeout(timeout);
  }
  return null;
}

Complete provider detection module implementation

Here's a production-ready implementation combining all detection methods:

interface ProviderResult {
  provider: string;
  confidence: 'high' | 'medium' | 'low';
  metadata?: Record<string, string | undefined>;
  method?: string;
}

class SandboxProviderDetector {
  private cachedResult: ProviderResult | null = null;
  
  // Order matters: most specific/reliable first
  private detectors = [
    this.detectE2B,
    this.detectVercel,
    this.detectModal,
    this.detectFlyIo,
    this.detectReplit,
    this.detectCodeSandbox,
    this.detectDaytona,
    this.detectGitHubCodespaces,
    this.detectRailway,
    this.detectRender,
  ];
  
  async detect(): Promise<ProviderResult> {
    if (this.cachedResult) return this.cachedResult;
    
    // Fast path: environment variable checks
    for (const detector of this.detectors) {
      const result = detector.call(this);
      if (result) {
        this.cachedResult = result;
        return result;
      }
    }
    
    // Slower path: container/VM detection
    const container = this.detectContainer();
    if (container) {
      this.cachedResult = container;
      return container;
    }
    
    // Slowest path: metadata service (only if needed)
    const cloud = await this.detectCloudViaMetadata();
    if (cloud) {
      this.cachedResult = cloud;
      return cloud;
    }
    
    return { provider: 'unknown', confidence: 'low' };
  }
  
  private detectE2B(): ProviderResult | null {
    if (process.env.E2B_SANDBOX === 'true') {
      return {
        provider: 'e2b',
        confidence: 'high',
        metadata: {
          sandboxId: process.env.E2B_SANDBOX_ID,
          teamId: process.env.E2B_TEAM_ID,
          templateId: process.env.E2B_TEMPLATE_ID,
        }
      };
    }
    return null;
  }
  
  private detectVercel(): ProviderResult | null {
    if (process.env.VERCEL === '1') {
      return {
        provider: 'vercel',
        confidence: 'high',
        metadata: {
          env: process.env.VERCEL_ENV,
          region: process.env.VERCEL_REGION,
          deploymentId: process.env.VERCEL_DEPLOYMENT_ID,
          runtime: typeof globalThis.EdgeRuntime !== 'undefined' ? 'edge' 
                 : process.env.LAMBDA_TASK_ROOT ? 'serverless' : 'static',
        }
      };
    }
    return null;
  }
  
  private detectModal(): ProviderResult | null {
    if (process.env.MODAL_IS_REMOTE === '1') {
      return {
        provider: 'modal',
        confidence: 'high',
        metadata: {
          cloudProvider: process.env.MODAL_CLOUD_PROVIDER,
          region: process.env.MODAL_REGION,
          type: process.env.MODAL_SANDBOX_ID ? 'sandbox' : 'function',
        }
      };
    }
    return null;
  }
  
  private detectFlyIo(): ProviderResult | null {
    if (process.env.FLY_APP_NAME) {
      return {
        provider: 'fly.io',
        confidence: 'high',
        metadata: {
          appName: process.env.FLY_APP_NAME,
          region: process.env.FLY_REGION,
          machineId: process.env.FLY_MACHINE_ID,
        }
      };
    }
    return null;
  }
  
  private detectReplit(): ProviderResult | null {
    if (process.env.REPL_ID) {
      return {
        provider: 'replit',
        confidence: 'high',
        metadata: {
          replId: process.env.REPL_ID,
          slug: process.env.REPL_SLUG,
          owner: process.env.REPL_OWNER,
        }
      };
    }
    return null;
  }
  
  private detectCodeSandbox(): ProviderResult | null {
    if (process.env.CODESANDBOX_HOST) {
      return {
        provider: 'codesandbox',
        confidence: 'high',
        metadata: { host: process.env.CODESANDBOX_HOST }
      };
    }
    return null;
  }
  
  private detectDaytona(): ProviderResult | null {
    const signals: string[] = [];
    if (os.userInfo().username === 'daytona') signals.push('user');
    if (fs.existsSync('/home/daytona')) signals.push('home');
    if (fs.existsSync(path.join(os.homedir(), '.daytona'))) signals.push('config');
    
    if (signals.length >= 2) {
      return { provider: 'daytona', confidence: 'medium', method: signals.join('+') };
    }
    return null;
  }
  
  private detectGitHubCodespaces(): ProviderResult | null {
    if (process.env.CODESPACES === 'true') {
      return {
        provider: 'github-codespaces',
        confidence: 'high',
        metadata: {
          name: process.env.CODESPACE_NAME,
          repo: process.env.GITHUB_REPOSITORY,
        }
      };
    }
    return null;
  }
  
  private detectRailway(): ProviderResult | null {
    if (process.env.RAILWAY_ENVIRONMENT) {
      return {
        provider: 'railway',
        confidence: 'high',
        metadata: {
          environment: process.env.RAILWAY_ENVIRONMENT,
          projectId: process.env.RAILWAY_PROJECT_ID,
        }
      };
    }
    return null;
  }
  
  private detectRender(): ProviderResult | null {
    if (process.env.RENDER === 'true') {
      return {
        provider: 'render',
        confidence: 'high',
        metadata: {
          serviceId: process.env.RENDER_SERVICE_ID,
          serviceName: process.env.RENDER_SERVICE_NAME,
        }
      };
    }
    return null;
  }
}

// Usage
const detector = new SandboxProviderDetector();
const provider = await detector.detect();
console.log(`Running on: ${provider.provider} (${provider.confidence} confidence)`);

Existing libraries you can use or reference

Several open-source projects implement cloud detection patterns:

cloud-detect (Python, pip install cloud-detect): Detects AWS, GCP, Azure, Alibaba, DigitalOcean, Oracle via filesystem + metadata
cloud-detect-js (Node, npm install cloud-detect-js): JavaScript port with similar feature coverage
banzaicloud/satellite (Go): Uses two-tier detection with sysfs first, then metadata fallback
OpenTelemetry Resource Detectors: Production-grade detectors across Node.js, Python, Go — use @opentelemetry/resource-detector-aws, @opentelemetry/resource-detector-gcp, etc.

The OpenTelemetry approach is particularly well-suited for telemetry libraries since it follows established semantic conventions for resource attributes.

Best practices for telemetry provider detection

Detection order should prioritize speed and reliability: environment variables (instant) → filesystem checks (<1ms) → DMI/sysfs (<10ms) → metadata services (100-500ms with timeout). Always cache results since the provider cannot change during process lifetime.

Privacy considerations: Collect only necessary identifiers (provider name, region), not instance IDs or machine identifiers. Allow users to opt out via environment variable like DISABLE_PROVIDER_DETECTION=true. Document what data is collected.

Fallback handling: Return { provider: 'unknown', confidence: 'low' } rather than throwing errors. Log detection method used for debugging. Consider exposing a FORCE_PROVIDER environment variable for testing and manual override.

Quick reference detection table

Provider	Primary Detection	Secondary Detection
E2B	`E2B_SANDBOX="true"`	`/run/e2b/.E2B_SANDBOX`
Vercel	`VERCEL="1"`	`LAMBDA_TASK_ROOT`, `EdgeRuntime` global
Modal	`MODAL_IS_REMOTE="1"`	`MODAL_CLOUD_PROVIDER`
Fly.io	`FLY_APP_NAME`	`FLY_MACHINE_ID`, `FLY_REGION`
Replit	`REPL_ID`	`.replit` file, `REPLIT_DB_URL`
CodeSandbox	`CODESANDBOX_HOST`	`CSB_BASE_PREVIEW_HOST`
Daytona	Username `daytona`	`/home/daytona`, `~/.daytona`
GitHub Codespaces	`CODESPACES="true"`	`CODESPACE_NAME`
Railway	`RAILWAY_ENVIRONMENT`	`RAILWAY_PROJECT_ID`
Render	`RENDER="true"`	`RENDER_SERVICE_ID`

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