feat: godoxy agent

agent/pkg/agent/bare_metal.go

@@ -0,0 +1,24 @@
+package agent
+
+import (
+	"bytes"
+	"strings"
+	"text/template"
+)
+
+var (
+	installScript = `AGENT_NAME="{{.Name}}" \
+	AGENT_PORT="{{.Port}}" \
+	AGENT_CA_CERT="{{.CACert}}" \
+	AGENT_SSL_CERT="{{.SSLCert}}" \
+	bash -c "$(curl -fsSL https://raw.githubusercontent.com/yusing/go-proxy/main/scripts/install-agent.sh)"`
+	installScriptTemplate = template.Must(template.New("install.sh").Parse(installScript))
+)
+
+func (c *AgentEnvConfig) Generate() (string, error) {
+	buf := bytes.NewBuffer(make([]byte, 0, 4096))
+	if err := installScriptTemplate.Execute(buf, c); err != nil {
+		return "", err
+	}
+	return strings.ReplaceAll(buf.String(), ";", "\\;"), nil
+}

agent/pkg/agent/config.go

@@ -0,0 +1,185 @@
+package agent
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/json"
+	"net"
+	"net/http"
+	"os"
+	"strings"
+	"time"
+
+	"github.com/rs/zerolog"
+	"github.com/yusing/go-proxy/agent/pkg/certs"
+	"github.com/yusing/go-proxy/internal/gperr"
+	"github.com/yusing/go-proxy/internal/logging"
+	gphttp "github.com/yusing/go-proxy/internal/net/gphttp"
+	"github.com/yusing/go-proxy/internal/net/types"
+	"github.com/yusing/go-proxy/internal/task"
+	"github.com/yusing/go-proxy/pkg"
+	"golang.org/x/net/context"
+)
+
+type AgentConfig struct {
+	Addr string
+
+	httpClient *http.Client
+	tlsConfig  *tls.Config
+	name       string
+	l          zerolog.Logger
+}
+
+const (
+	EndpointVersion    = "/version"
+	EndpointName       = "/name"
+	EndpointProxyHTTP  = "/proxy/http"
+	EndpointHealth     = "/health"
+	EndpointLogs       = "/logs"
+	EndpointSystemInfo = "/system_info"
+
+	AgentHost = CertsDNSName
+
+	APIEndpointBase = "/godoxy/agent"
+	APIBaseURL      = "https://" + AgentHost + APIEndpointBase
+
+	DockerHost = "https://" + AgentHost
+
+	FakeDockerHostPrefix    = "agent://"
+	FakeDockerHostPrefixLen = len(FakeDockerHostPrefix)
+)
+
+var (
+	AgentURL              = types.MustParseURL(APIBaseURL)
+	HTTPProxyURL          = types.MustParseURL(APIBaseURL + EndpointProxyHTTP)
+	HTTPProxyURLPrefixLen = len(APIEndpointBase + EndpointProxyHTTP)
+)
+
+func IsDockerHostAgent(dockerHost string) bool {
+	return strings.HasPrefix(dockerHost, FakeDockerHostPrefix)
+}
+
+func GetAgentAddrFromDockerHost(dockerHost string) string {
+	return dockerHost[FakeDockerHostPrefixLen:]
+}
+
+func (cfg *AgentConfig) FakeDockerHost() string {
+	return FakeDockerHostPrefix + cfg.Addr
+}
+
+func (cfg *AgentConfig) Parse(addr string) error {
+	cfg.Addr = addr
+	return nil
+}
+
+func withoutBuildTime(version string) string {
+	return strings.Split(version, "-")[0]
+}
+
+func checkVersion(a, b string) bool {
+	return withoutBuildTime(a) == withoutBuildTime(b)
+}
+
+func (cfg *AgentConfig) StartWithCerts(parent task.Parent, ca, crt, key []byte) error {
+	clientCert, err := tls.X509KeyPair(crt, key)
+	if err != nil {
+		return err
+	}
+
+	// create tls config
+	caCertPool := x509.NewCertPool()
+	ok := caCertPool.AppendCertsFromPEM(ca)
+	if !ok {
+		return gperr.New("invalid ca certificate")
+	}
+
+	cfg.tlsConfig = &tls.Config{
+		Certificates: []tls.Certificate{clientCert},
+		RootCAs:      caCertPool,
+		ServerName:   CertsDNSName,
+	}
+
+	// create transport and http client
+	cfg.httpClient = cfg.NewHTTPClient()
+
+	ctx, cancel := context.WithTimeout(parent.Context(), 5*time.Second)
+	defer cancel()
+
+	// check agent version
+	version, _, err := cfg.Fetch(ctx, EndpointVersion)
+	if err != nil {
+		return err
+	}
+
+	versionStr := string(version)
+	// skip version check for dev versions
+	if strings.HasPrefix(versionStr, "v") && !checkVersion(versionStr, pkg.GetVersion()) {
+		return gperr.Errorf("agent version mismatch: server: %s, agent: %s", pkg.GetVersion(), versionStr)
+	}
+
+	// get agent name
+	name, _, err := cfg.Fetch(ctx, EndpointName)
+	if err != nil {
+		return err
+	}
+
+	cfg.name = string(name)
+	cfg.l = logging.With().Str("agent", cfg.name).Logger()
+
+	logging.Info().Msgf("agent %q initialized", cfg.name)
+	return nil
+}
+
+func (cfg *AgentConfig) Start(parent task.Parent) gperr.Error {
+	certData, err := os.ReadFile(certs.AgentCertsFilename(cfg.Addr))
+	if err != nil {
+		return gperr.Wrap(err, "failed to read agent certs")
+	}
+
+	ca, crt, key, err := certs.ExtractCert(certData)
+	if err != nil {
+		return gperr.Wrap(err, "failed to extract agent certs")
+	}
+
+	return gperr.Wrap(cfg.StartWithCerts(parent, ca, crt, key))
+}
+
+func (cfg *AgentConfig) NewHTTPClient() *http.Client {
+	return &http.Client{
+		Transport: cfg.Transport(),
+	}
+}
+
+func (cfg *AgentConfig) Transport() *http.Transport {
+	return &http.Transport{
+		DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+			if addr != AgentHost+":443" {
+				return nil, &net.AddrError{Err: "invalid address", Addr: addr}
+			}
+			if network != "tcp" {
+				return nil, &net.OpError{Op: "dial", Net: network, Source: nil, Addr: nil}
+			}
+			return cfg.DialContext(ctx)
+		},
+		TLSClientConfig: cfg.tlsConfig,
+	}
+}
+
+func (cfg *AgentConfig) DialContext(ctx context.Context) (net.Conn, error) {
+	return gphttp.DefaultDialer.DialContext(ctx, "tcp", cfg.Addr)
+}
+
+func (cfg *AgentConfig) Name() string {
+	return cfg.name
+}
+
+func (cfg *AgentConfig) String() string {
+	return cfg.name + "@" + cfg.Addr
+}
+
+func (cfg *AgentConfig) MarshalJSON() ([]byte, error) {
+	return json.Marshal(map[string]string{
+		"name": cfg.Name(),
+		"addr": cfg.Addr,
+	})
+}

agent/pkg/agent/docker_compose.go

@@ -0,0 +1,27 @@
+package agent
+
+import (
+	"bytes"
+	"text/template"
+
+	_ "embed"
+)
+
+var (
+	//go:embed templates/agent.compose.yml
+	agentComposeYAML         string
+	agentComposeYAMLTemplate = template.Must(template.New("agent.compose.yml").Parse(agentComposeYAML))
+)
+
+const (
+	DockerImageProduction = "ghcr.io/yusing/godoxy-agent:latest"
+	DockerImageNightly    = "ghcr.io/yusing/godoxy-agent:nightly"
+)
+
+func (c *AgentComposeConfig) Generate() (string, error) {
+	buf := bytes.NewBuffer(make([]byte, 0, 1024))
+	if err := agentComposeYAMLTemplate.Execute(buf, c); err != nil {
+		return "", err
+	}
+	return buf.String(), nil
+}

agent/pkg/agent/env.go

@@ -0,0 +1,17 @@
+package agent
+
+type (
+	AgentEnvConfig struct {
+		Name    string
+		Port    int
+		CACert  string
+		SSLCert string
+	}
+	AgentComposeConfig struct {
+		Image string
+		*AgentEnvConfig
+	}
+	Generator interface {
+		Generate() (string, error)
+	}
+)

agent/pkg/agent/new_agent.go

@@ -0,0 +1,139 @@
+package agent
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/tls"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/base64"
+	"encoding/pem"
+	"errors"
+	"math/big"
+	"strings"
+	"time"
+)
+
+const (
+	CertsDNSName = "godoxy.agent"
+	KeySize      = 2048
+)
+
+func toPEMPair(certDER []byte, key *rsa.PrivateKey) *PEMPair {
+	return &PEMPair{
+		Cert: pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: certDER}),
+		Key:  pem.EncodeToMemory(&pem.Block{Type: "RSA PRIVATE KEY", Bytes: x509.MarshalPKCS1PrivateKey(key)}),
+	}
+}
+
+func b64Encode(data []byte) string {
+	return base64.StdEncoding.EncodeToString(data)
+}
+
+func b64Decode(data string) ([]byte, error) {
+	return base64.StdEncoding.DecodeString(data)
+}
+
+type PEMPair struct {
+	Cert, Key []byte
+}
+
+func (p *PEMPair) String() string {
+	return b64Encode(p.Cert) + ";" + b64Encode(p.Key)
+}
+
+func (p *PEMPair) Load(data string) (err error) {
+	parts := strings.Split(data, ";")
+	if len(parts) != 2 {
+		return errors.New("invalid PEM pair")
+	}
+	p.Cert, err = b64Decode(parts[0])
+	if err != nil {
+		return err
+	}
+	p.Key, err = b64Decode(parts[1])
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (p *PEMPair) ToTLSCert() (*tls.Certificate, error) {
+	cert, err := tls.X509KeyPair(p.Cert, p.Key)
+	return &cert, err
+}
+
+func NewAgent() (ca, srv, client *PEMPair, err error) {
+	// Create the CA's certificate
+	caTemplate := &x509.Certificate{
+		SerialNumber: big.NewInt(1),
+		Subject: pkix.Name{
+			Organization: []string{"GoDoxy"},
+			CommonName:   CertsDNSName,
+		},
+		NotBefore:             time.Now(),
+		NotAfter:              time.Now().AddDate(1000, 0, 0), // 1000 years
+		KeyUsage:              x509.KeyUsageCertSign | x509.KeyUsageCRLSign,
+		BasicConstraintsValid: true,
+		IsCA:                  true,
+	}
+
+	caKey, err := rsa.GenerateKey(rand.Reader, KeySize)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	caDER, err := x509.CreateCertificate(rand.Reader, caTemplate, caTemplate, &caKey.PublicKey, caKey)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	ca = toPEMPair(caDER, caKey)
+
+	// Generate a new private key for the server certificate
+	serverKey, err := rsa.GenerateKey(rand.Reader, KeySize)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	srvTemplate := &x509.Certificate{
+		SerialNumber: big.NewInt(2),
+		Issuer:       caTemplate.Subject,
+		Subject:      caTemplate.Subject,
+		DNSNames:     []string{CertsDNSName},
+		NotBefore:    time.Now(),
+		NotAfter:     time.Now().AddDate(1000, 0, 0), // Add validity period
+		KeyUsage:     x509.KeyUsageDigitalSignature,
+		ExtKeyUsage:  []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
+	}
+
+	srvCertDER, err := x509.CreateCertificate(rand.Reader, srvTemplate, caTemplate, &serverKey.PublicKey, caKey)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	srv = toPEMPair(srvCertDER, serverKey)
+
+	clientKey, err := rsa.GenerateKey(rand.Reader, KeySize)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	clientTemplate := &x509.Certificate{
+		SerialNumber: big.NewInt(3),
+		Issuer:       caTemplate.Subject,
+		Subject:      caTemplate.Subject,
+		DNSNames:     []string{CertsDNSName},
+		NotBefore:    time.Now(),
+		NotAfter:     time.Now().AddDate(1000, 0, 0),
+		KeyUsage:     x509.KeyUsageDigitalSignature,
+		ExtKeyUsage:  []x509.ExtKeyUsage{x509.ExtKeyUsageClientAuth},
+	}
+	clientCertDER, err := x509.CreateCertificate(rand.Reader, clientTemplate, caTemplate, &clientKey.PublicKey, caKey)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+
+	client = toPEMPair(clientCertDER, clientKey)
+	return
+}

agent/pkg/agent/new_agent_test.go

@@ -0,0 +1,91 @@
+package agent
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	. "github.com/yusing/go-proxy/internal/utils/testing"
+)
+
+func TestNewAgent(t *testing.T) {
+	ca, srv, client, err := NewAgent()
+	ExpectNoError(t, err)
+	ExpectTrue(t, ca != nil)
+	ExpectTrue(t, srv != nil)
+	ExpectTrue(t, client != nil)
+}
+
+func TestPEMPair(t *testing.T) {
+	ca, srv, client, err := NewAgent()
+	ExpectNoError(t, err)
+
+	for i, p := range []*PEMPair{ca, srv, client} {
+		t.Run(fmt.Sprintf("load-%d", i), func(t *testing.T) {
+			var pp PEMPair
+			err := pp.Load(p.String())
+			ExpectNoError(t, err)
+			ExpectBytesEqual(t, p.Cert, pp.Cert)
+			ExpectBytesEqual(t, p.Key, pp.Key)
+		})
+	}
+}
+
+func TestPEMPairToTLSCert(t *testing.T) {
+	ca, srv, client, err := NewAgent()
+	ExpectNoError(t, err)
+
+	for i, p := range []*PEMPair{ca, srv, client} {
+		t.Run(fmt.Sprintf("toTLSCert-%d", i), func(t *testing.T) {
+			cert, err := p.ToTLSCert()
+			ExpectNoError(t, err)
+			ExpectTrue(t, cert != nil)
+		})
+	}
+}
+
+func TestServerClient(t *testing.T) {
+	ca, srv, client, err := NewAgent()
+	ExpectNoError(t, err)
+
+	srvTLS, err := srv.ToTLSCert()
+	ExpectNoError(t, err)
+	ExpectTrue(t, srvTLS != nil)
+
+	clientTLS, err := client.ToTLSCert()
+	ExpectNoError(t, err)
+	ExpectTrue(t, clientTLS != nil)
+
+	caPool := x509.NewCertPool()
+	ExpectTrue(t, caPool.AppendCertsFromPEM(ca.Cert))
+
+	srvTLSConfig := &tls.Config{
+		Certificates: []tls.Certificate{*srvTLS},
+		ClientCAs:    caPool,
+		ClientAuth:   tls.RequireAndVerifyClientCert,
+	}
+
+	clientTLSConfig := &tls.Config{
+		Certificates: []tls.Certificate{*clientTLS},
+		RootCAs:      caPool,
+		ServerName:   CertsDNSName,
+	}
+
+	server := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+	server.TLS = srvTLSConfig
+	server.StartTLS()
+	defer server.Close()
+
+	httpClient := &http.Client{
+		Transport: &http.Transport{TLSClientConfig: clientTLSConfig},
+	}
+
+	resp, err := httpClient.Get(server.URL)
+	ExpectNoError(t, err)
+	ExpectEqual(t, resp.StatusCode, http.StatusOK)
+}

agent/pkg/agent/requests.go

@@ -0,0 +1,49 @@
+package agent
+
+import (
+	"io"
+	"net/http"
+
+	"github.com/coder/websocket"
+	"golang.org/x/net/context"
+)
+
+func (cfg *AgentConfig) Do(ctx context.Context, method, endpoint string, body io.Reader) (*http.Response, error) {
+	req, err := http.NewRequestWithContext(ctx, method, APIBaseURL+endpoint, body)
+	if err != nil {
+		return nil, err
+	}
+	return cfg.httpClient.Do(req)
+}
+
+func (cfg *AgentConfig) Forward(req *http.Request, endpoint string) ([]byte, int, error) {
+	req = req.WithContext(req.Context())
+	req.URL.Host = AgentHost
+	req.URL.Scheme = "https"
+	req.URL.Path = APIEndpointBase + endpoint
+	req.RequestURI = ""
+	resp, err := cfg.httpClient.Do(req)
+	if err != nil {
+		return nil, 0, err
+	}
+	defer resp.Body.Close()
+	data, _ := io.ReadAll(resp.Body)
+	return data, resp.StatusCode, nil
+}
+
+func (cfg *AgentConfig) Fetch(ctx context.Context, endpoint string) ([]byte, int, error) {
+	resp, err := cfg.Do(ctx, "GET", endpoint, nil)
+	if err != nil {
+		return nil, 0, err
+	}
+	defer resp.Body.Close()
+	data, _ := io.ReadAll(resp.Body)
+	return data, resp.StatusCode, nil
+}
+
+func (cfg *AgentConfig) Websocket(ctx context.Context, endpoint string) (*websocket.Conn, *http.Response, error) {
+	return websocket.Dial(ctx, APIBaseURL+endpoint, &websocket.DialOptions{
+		HTTPClient: cfg.NewHTTPClient(),
+		Host:       AgentHost,
+	})
+}

agent/pkg/agent/templates/agent.compose.yml

@@ -0,0 +1,14 @@
+services:
+  agent:
+    image: "{{.Image}}"
+    container_name: godoxy-agent
+    restart: always
+    network_mode: host # do not change this
+    environment:
+      AGENT_NAME: "{{.Name}}"
+      AGENT_PORT: "{{.Port}}"
+      AGENT_CA_CERT: "{{.CACert}}"
+      AGENT_SSL_CERT: "{{.SSLCert}}"
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+      - ./data:/app/data

agent/pkg/agentproxy/headers.go

@@ -0,0 +1,27 @@
+package agentproxy
+
+import (
+	"net/http"
+	"strconv"
+)
+
+const (
+	HeaderXProxyHost                  = "X-Proxy-Host"
+	HeaderXProxyHTTPS                 = "X-Proxy-Https"
+	HeaderXProxySkipTLSVerify         = "X-Proxy-Skip-Tls-Verify"
+	HeaderXProxyResponseHeaderTimeout = "X-Proxy-Response-Header-Timeout"
+)
+
+type AgentProxyHeaders struct {
+	Host                  string
+	IsHTTPS               bool
+	SkipTLSVerify         bool
+	ResponseHeaderTimeout int
+}
+
+func SetAgentProxyHeaders(r *http.Request, headers *AgentProxyHeaders) {
+	r.Header.Set(HeaderXProxyHost, headers.Host)
+	r.Header.Set(HeaderXProxyHTTPS, strconv.FormatBool(headers.IsHTTPS))
+	r.Header.Set(HeaderXProxySkipTLSVerify, strconv.FormatBool(headers.SkipTLSVerify))
+	r.Header.Set(HeaderXProxyResponseHeaderTimeout, strconv.Itoa(headers.ResponseHeaderTimeout))
+}

agent/pkg/certs/zip.go

@@ -0,0 +1,76 @@
+package certs
+
+import (
+	"archive/zip"
+	"bytes"
+	"io"
+	"path/filepath"
+
+	"github.com/yusing/go-proxy/internal/common"
+)
+
+func writeFile(zipWriter *zip.Writer, name string, data []byte) error {
+	w, err := zipWriter.CreateHeader(&zip.FileHeader{
+		Name:   name,
+		Method: zip.Store,
+	})
+	if err != nil {
+		return err
+	}
+	_, err = w.Write(data)
+	return err
+}
+
+func readFile(f *zip.File) ([]byte, error) {
+	r, err := f.Open()
+	if err != nil {
+		return nil, err
+	}
+	defer r.Close()
+	return io.ReadAll(r)
+}
+
+func ZipCert(ca, crt, key []byte) ([]byte, error) {
+	data := bytes.NewBuffer(make([]byte, 0, 6144))
+	zipWriter := zip.NewWriter(data)
+	defer zipWriter.Close()
+
+	if err := writeFile(zipWriter, "ca.pem", ca); err != nil {
+		return nil, err
+	}
+	if err := writeFile(zipWriter, "cert.pem", crt); err != nil {
+		return nil, err
+	}
+	if err := writeFile(zipWriter, "key.pem", key); err != nil {
+		return nil, err
+	}
+	if err := zipWriter.Close(); err != nil {
+		return nil, err
+	}
+	return data.Bytes(), nil
+}
+
+func AgentCertsFilename(host string) string {
+	return filepath.Join(common.AgentCertsBasePath, host+".zip")
+}
+
+func ExtractCert(data []byte) (ca, crt, key []byte, err error) {
+	zipReader, err := zip.NewReader(bytes.NewReader(data), int64(len(data)))
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	for _, file := range zipReader.File {
+		switch file.Name {
+		case "ca.pem":
+			ca, err = readFile(file)
+		case "cert.pem":
+			crt, err = readFile(file)
+		case "key.pem":
+			key, err = readFile(file)
+		}
+		if err != nil {
+			return nil, nil, nil, err
+		}
+	}
+	return ca, crt, key, nil
+}

agent/pkg/certs/zip_test.go

@@ -0,0 +1,19 @@
+package certs
+
+import (
+	"testing"
+
+	. "github.com/yusing/go-proxy/internal/utils/testing"
+)
+
+func TestZipCert(t *testing.T) {
+	ca, crt, key := []byte("test1"), []byte("test2"), []byte("test3")
+	zipData, err := ZipCert(ca, crt, key)
+	ExpectNoError(t, err)
+
+	ca2, crt2, key2, err := ExtractCert(zipData)
+	ExpectNoError(t, err)
+	ExpectBytesEqual(t, ca, ca2)
+	ExpectBytesEqual(t, crt, crt2)
+	ExpectBytesEqual(t, key, key2)
+}

agent/pkg/env/env.go

@@ -0,0 +1,25 @@
+package env
+
+import (
+	"os"
+
+	"github.com/yusing/go-proxy/internal/common"
+)
+
+func DefaultAgentName() string {
+	name, err := os.Hostname()
+	if err != nil {
+		return "agent"
+	}
+	return name
+}
+
+var (
+	AgentName                = common.GetEnvString("AGENT_NAME", DefaultAgentName())
+	AgentPort                = common.GetEnvInt("AGENT_PORT", 8890)
+	AgentRegistrationPort    = common.GetEnvInt("AGENT_REGISTRATION_PORT", 8891)
+	AgentSkipClientCertCheck = common.GetEnvBool("AGENT_SKIP_CLIENT_CERT_CHECK", false)
+
+	AgentCACert  = common.GetEnvString("AGENT_CA_CERT", "")
+	AgentSSLCert = common.GetEnvString("AGENT_SSL_CERT", "")
+)

agent/pkg/handler/check_health.go

@@ -0,0 +1,78 @@
+package handler
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+
+	"github.com/yusing/go-proxy/internal/net/gphttp"
+	"github.com/yusing/go-proxy/internal/net/types"
+	"github.com/yusing/go-proxy/internal/watcher/health"
+	"github.com/yusing/go-proxy/internal/watcher/health/monitor"
+)
+
+var defaultHealthConfig = health.DefaultHealthConfig()
+
+func CheckHealth(w http.ResponseWriter, r *http.Request) {
+	query := r.URL.Query()
+	scheme := query.Get("scheme")
+	if scheme == "" {
+		http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
+		return
+	}
+
+	var result *health.HealthCheckResult
+	var err error
+	switch scheme {
+	case "fileserver":
+		path := query.Get("path")
+		if path == "" {
+			http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
+			return
+		}
+		_, err := os.Stat(path)
+		result = &health.HealthCheckResult{Healthy: err == nil}
+		if err != nil {
+			result.Detail = err.Error()
+		}
+	case "http", "https": // path is optional
+		host := query.Get("host")
+		path := query.Get("path")
+		if host == "" {
+			http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
+			return
+		}
+		result, err = monitor.NewHTTPHealthChecker(types.NewURL(&url.URL{
+			Scheme: scheme,
+			Host:   host,
+			Path:   path,
+		}), defaultHealthConfig).CheckHealth()
+	case "tcp", "udp":
+		host := query.Get("host")
+		if host == "" {
+			http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
+			return
+		}
+		hasPort := strings.Contains(host, ":")
+		port := query.Get("port")
+		if port != "" && !hasPort {
+			host = fmt.Sprintf("%s:%s", host, port)
+		} else {
+			http.Error(w, http.StatusText(http.StatusBadRequest), http.StatusBadRequest)
+			return
+		}
+		result, err = monitor.NewRawHealthChecker(types.NewURL(&url.URL{
+			Scheme: scheme,
+			Host:   host,
+		}), defaultHealthConfig).CheckHealth()
+	}
+
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadGateway)
+		return
+	}
+
+	gphttp.RespondJSON(w, r, result)
+}

agent/pkg/handler/check_health_test.go

@@ -0,0 +1,216 @@
+package handler_test
+
+import (
+	"encoding/json"
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"net/url"
+	"strconv"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"github.com/yusing/go-proxy/agent/pkg/agent"
+	"github.com/yusing/go-proxy/agent/pkg/handler"
+	"github.com/yusing/go-proxy/internal/watcher/health"
+)
+
+func TestCheckHealthHTTP(t *testing.T) {
+	tests := []struct {
+		name            string
+		setupServer     func() *httptest.Server
+		queryParams     map[string]string
+		expectedStatus  int
+		expectedHealthy bool
+	}{
+		{
+			name: "Valid",
+			setupServer: func() *httptest.Server {
+				return httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+					w.WriteHeader(http.StatusOK)
+				}))
+			},
+			queryParams: map[string]string{
+				"scheme": "http",
+				"host":   "localhost",
+				"path":   "/",
+			},
+			expectedStatus:  http.StatusOK,
+			expectedHealthy: true,
+		},
+		{
+			name:        "InvalidQuery",
+			setupServer: nil,
+			queryParams: map[string]string{
+				"scheme": "http",
+			},
+			expectedStatus: http.StatusBadRequest,
+		},
+		{
+			name:        "ConnectionError",
+			setupServer: nil,
+			queryParams: map[string]string{
+				"scheme": "http",
+				"host":   "localhost:12345",
+			},
+			expectedStatus:  http.StatusOK,
+			expectedHealthy: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var server *httptest.Server
+			if tt.setupServer != nil {
+				server = tt.setupServer()
+				defer server.Close()
+				u, _ := url.Parse(server.URL)
+				tt.queryParams["scheme"] = u.Scheme
+				tt.queryParams["host"] = u.Host
+				tt.queryParams["path"] = u.Path
+			}
+
+			recorder := httptest.NewRecorder()
+			query := url.Values{}
+			for key, value := range tt.queryParams {
+				query.Set(key, value)
+			}
+			request := httptest.NewRequest(http.MethodGet, agent.APIEndpointBase+agent.EndpointHealth+"?"+query.Encode(), nil)
+			handler.CheckHealth(recorder, request)
+
+			require.Equal(t, recorder.Code, tt.expectedStatus)
+
+			if tt.expectedStatus == http.StatusOK {
+				var result health.HealthCheckResult
+				require.NoError(t, json.Unmarshal(recorder.Body.Bytes(), &result))
+				require.Equal(t, result.Healthy, tt.expectedHealthy)
+			}
+		})
+	}
+}
+
+func TestCheckHealthFileServer(t *testing.T) {
+	tests := []struct {
+		name            string
+		path            string
+		expectedStatus  int
+		expectedHealthy bool
+		expectedDetail  string
+	}{
+		{
+			name:            "ValidPath",
+			path:            t.TempDir(),
+			expectedStatus:  http.StatusOK,
+			expectedHealthy: true,
+			expectedDetail:  "",
+		},
+		{
+			name:            "InvalidPath",
+			path:            "/invalid",
+			expectedStatus:  http.StatusOK,
+			expectedHealthy: false,
+			expectedDetail:  "stat /invalid: no such file or directory",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			query := url.Values{}
+			query.Set("scheme", "fileserver")
+			query.Set("path", tt.path)
+
+			recorder := httptest.NewRecorder()
+			request := httptest.NewRequest(http.MethodGet, agent.APIEndpointBase+agent.EndpointHealth+"?"+query.Encode(), nil)
+			handler.CheckHealth(recorder, request)
+
+			require.Equal(t, recorder.Code, tt.expectedStatus)
+
+			var result health.HealthCheckResult
+			require.NoError(t, json.Unmarshal(recorder.Body.Bytes(), &result))
+			require.Equal(t, result.Healthy, tt.expectedHealthy)
+			require.Equal(t, result.Detail, tt.expectedDetail)
+		})
+	}
+}
+
+func TestCheckHealthTCPUDP(t *testing.T) {
+	tcp, err := net.Listen("tcp", "localhost:0")
+	require.NoError(t, err)
+	go func() {
+		conn, err := tcp.Accept()
+		require.NoError(t, err)
+		conn.Close()
+	}()
+
+	udp, err := net.ListenPacket("udp", "localhost:0")
+	require.NoError(t, err)
+	go func() {
+		buf := make([]byte, 1024)
+		n, addr, err := udp.ReadFrom(buf)
+		require.NoError(t, err)
+		require.Equal(t, string(buf[:n]), "ping")
+		_, _ = udp.WriteTo([]byte("pong"), addr)
+		udp.Close()
+	}()
+
+	tests := []struct {
+		name            string
+		scheme          string
+		host            string
+		port            int
+		expectedStatus  int
+		expectedHealthy bool
+	}{
+		{
+			name:            "ValidTCP",
+			scheme:          "tcp",
+			host:            "localhost",
+			port:            tcp.Addr().(*net.TCPAddr).Port,
+			expectedStatus:  http.StatusOK,
+			expectedHealthy: true,
+		},
+		{
+			name:            "InvalidHost",
+			scheme:          "tcp",
+			host:            "invalid",
+			port:            8080,
+			expectedStatus:  http.StatusOK,
+			expectedHealthy: false,
+		},
+		{
+			name:            "ValidUDP",
+			scheme:          "udp",
+			host:            "localhost",
+			port:            udp.LocalAddr().(*net.UDPAddr).Port,
+			expectedStatus:  http.StatusOK,
+			expectedHealthy: true,
+		},
+		{
+			name:            "InvalidHost",
+			scheme:          "udp",
+			host:            "invalid",
+			port:            8080,
+			expectedStatus:  http.StatusOK,
+			expectedHealthy: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			query := url.Values{}
+			query.Set("scheme", tt.scheme)
+			query.Set("host", tt.host)
+			query.Set("port", strconv.Itoa(tt.port))
+
+			recorder := httptest.NewRecorder()
+			request := httptest.NewRequest(http.MethodGet, agent.APIEndpointBase+agent.EndpointHealth+"?"+query.Encode(), nil)
+			handler.CheckHealth(recorder, request)
+
+			require.Equal(t, recorder.Code, tt.expectedStatus)
+
+			var result health.HealthCheckResult
+			require.NoError(t, json.Unmarshal(recorder.Body.Bytes(), &result))
+			require.Equal(t, result.Healthy, tt.expectedHealthy)
+		})
+	}
+}

agent/pkg/handler/docker_socket.go

@@ -0,0 +1,31 @@
+package handler
+
+import (
+	"net/http"
+	"net/url"
+
+	"github.com/docker/docker/client"
+	"github.com/yusing/go-proxy/internal/common"
+	"github.com/yusing/go-proxy/internal/docker"
+	"github.com/yusing/go-proxy/internal/logging"
+	"github.com/yusing/go-proxy/internal/net/gphttp/reverseproxy"
+	"github.com/yusing/go-proxy/internal/net/types"
+)
+
+func serviceUnavailable(w http.ResponseWriter, r *http.Request) {
+	http.Error(w, "docker socket is not available", http.StatusServiceUnavailable)
+}
+
+func DockerSocketHandler() http.HandlerFunc {
+	dockerClient, err := docker.NewClient(common.DockerHostFromEnv)
+	if err != nil {
+		logging.Warn().Err(err).Msg("failed to connect to docker client")
+		return serviceUnavailable
+	}
+	rp := reverseproxy.NewReverseProxy("docker", types.NewURL(&url.URL{
+		Scheme: "http",
+		Host:   client.DummyHost,
+	}), dockerClient.HTTPClient().Transport)
+
+	return rp.ServeHTTP
+}

agent/pkg/handler/handler.go

@@ -0,0 +1,49 @@
+package handler
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/yusing/go-proxy/agent/pkg/agent"
+	"github.com/yusing/go-proxy/agent/pkg/env"
+	v1 "github.com/yusing/go-proxy/internal/api/v1"
+	"github.com/yusing/go-proxy/internal/logging/memlogger"
+	"github.com/yusing/go-proxy/internal/metrics/systeminfo"
+	"github.com/yusing/go-proxy/internal/utils/strutils"
+)
+
+type ServeMux struct{ *http.ServeMux }
+
+func (mux ServeMux) HandleMethods(methods, endpoint string, handler http.HandlerFunc) {
+	for _, m := range strutils.CommaSeperatedList(methods) {
+		mux.ServeMux.HandleFunc(m+" "+agent.APIEndpointBase+endpoint, handler)
+	}
+}
+
+func (mux ServeMux) HandleFunc(endpoint string, handler http.HandlerFunc) {
+	mux.ServeMux.HandleFunc(agent.APIEndpointBase+endpoint, handler)
+}
+
+type NopWriteCloser struct {
+	io.Writer
+}
+
+func (NopWriteCloser) Close() error {
+	return nil
+}
+
+func NewAgentHandler() http.Handler {
+	mux := ServeMux{http.NewServeMux()}
+
+	mux.HandleFunc(agent.EndpointProxyHTTP+"/{path...}", ProxyHTTP)
+	mux.HandleMethods("GET", agent.EndpointVersion, v1.GetVersion)
+	mux.HandleMethods("GET", agent.EndpointName, func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprint(w, env.AgentName)
+	})
+	mux.HandleMethods("GET", agent.EndpointHealth, CheckHealth)
+	mux.HandleMethods("GET", agent.EndpointLogs, memlogger.HandlerFunc())
+	mux.HandleMethods("GET", agent.EndpointSystemInfo, systeminfo.Poller.ServeHTTP)
+	mux.ServeMux.HandleFunc("/", DockerSocketHandler())
+	return mux
+}

agent/pkg/handler/proxy_http.go

@@ -0,0 +1,63 @@
+package handler
+
+import (
+	"crypto/tls"
+	"net/http"
+	"net/url"
+	"strconv"
+	"time"
+
+	"github.com/yusing/go-proxy/agent/pkg/agent"
+	"github.com/yusing/go-proxy/agent/pkg/agentproxy"
+	"github.com/yusing/go-proxy/internal/logging"
+	"github.com/yusing/go-proxy/internal/net/gphttp"
+	"github.com/yusing/go-proxy/internal/net/gphttp/reverseproxy"
+	"github.com/yusing/go-proxy/internal/net/types"
+	"github.com/yusing/go-proxy/internal/utils/strutils"
+)
+
+func ProxyHTTP(w http.ResponseWriter, r *http.Request) {
+	host := r.Header.Get(agentproxy.HeaderXProxyHost)
+	isHTTPS := strutils.ParseBool(r.Header.Get(agentproxy.HeaderXProxyHTTPS))
+	skipTLSVerify := strutils.ParseBool(r.Header.Get(agentproxy.HeaderXProxySkipTLSVerify))
+	responseHeaderTimeout, err := strconv.Atoi(r.Header.Get(agentproxy.HeaderXProxyResponseHeaderTimeout))
+	if err != nil {
+		responseHeaderTimeout = 0
+	}
+
+	if host == "" {
+		http.Error(w, "missing required headers", http.StatusBadRequest)
+		return
+	}
+
+	scheme := "http"
+	if isHTTPS {
+		scheme = "https"
+	}
+
+	var transport *http.Transport
+	if skipTLSVerify {
+		transport = gphttp.NewTransportWithTLSConfig(&tls.Config{InsecureSkipVerify: true})
+	} else {
+		transport = gphttp.NewTransport()
+	}
+
+	if responseHeaderTimeout > 0 {
+		transport.ResponseHeaderTimeout = time.Duration(responseHeaderTimeout) * time.Second
+	}
+
+	r.URL.Scheme = ""
+	r.URL.Host = ""
+	r.URL.Path = r.URL.Path[agent.HTTPProxyURLPrefixLen:] // strip the {API_BASE}/proxy/http prefix
+	r.RequestURI = r.URL.String()
+	r.URL.Host = host
+	r.URL.Scheme = scheme
+
+	logging.Debug().Msgf("proxy http request: %s %s", r.Method, r.URL.String())
+
+	rp := reverseproxy.NewReverseProxy("agent", types.NewURL(&url.URL{
+		Scheme: scheme,
+		Host:   host,
+	}), transport)
+	rp.ServeHTTP(w, r)
+}

agent/pkg/server/server.go

@@ -0,0 +1,51 @@
+package server
+
+import (
+	"crypto/tls"
+	"crypto/x509"
+	"encoding/pem"
+	"fmt"
+	"net/http"
+
+	"github.com/yusing/go-proxy/agent/pkg/env"
+	"github.com/yusing/go-proxy/agent/pkg/handler"
+	"github.com/yusing/go-proxy/internal/logging"
+	"github.com/yusing/go-proxy/internal/net/gphttp/server"
+	"github.com/yusing/go-proxy/internal/task"
+)
+
+type Options struct {
+	CACert, ServerCert *tls.Certificate
+	Port               int
+}
+
+func StartAgentServer(parent task.Parent, opt Options) {
+	t := parent.Subtask("agent_server")
+
+	caCertPEM := pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: opt.CACert.Certificate[0]})
+	caCertPool := x509.NewCertPool()
+	caCertPool.AppendCertsFromPEM(caCertPEM)
+
+	// Configure TLS
+	tlsConfig := &tls.Config{
+		Certificates: []tls.Certificate{*opt.ServerCert},
+		ClientCAs:    caCertPool,
+		ClientAuth:   tls.RequireAndVerifyClientCert,
+	}
+
+	if env.AgentSkipClientCertCheck {
+		tlsConfig.ClientAuth = tls.NoClientCert
+	}
+
+	logger := logging.GetLogger()
+	agentServer := &http.Server{
+		Addr:      fmt.Sprintf(":%d", opt.Port),
+		Handler:   handler.NewAgentHandler(),
+		TLSConfig: tlsConfig,
+	}
+
+	server.Start(t, agentServer, logger)
+	t.OnCancel("stop", func() {
+		server.Stop(agentServer, logger)
+	})
+}