envoy: Initial changes

internal/envoy/envoy.go

@@ -0,0 +1,158 @@
+// Package envoy creates and configures an envoy server.
+package envoy
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/natefinch/atomic"
+	"github.com/pomerium/pomerium/internal/log"
+	"github.com/rs/zerolog"
+)
+
+const (
+	workingDirectoryName = ".pomerium-envoy"
+	configFileName       = "envoy-config.yaml"
+)
+
+// A Server is a pomerium proxy implemented via envoy.
+type Server struct {
+	wd  string
+	cmd *exec.Cmd
+
+	grpcPort, httpPort string
+}
+
+// NewServer creates a new server with traffic routed by envoy.
+func NewServer(grpcPort, httpPort string) (*Server, error) {
+	wd := filepath.Join(os.TempDir(), workingDirectoryName)
+	err := os.MkdirAll(wd, 0755)
+	if err != nil {
+		return nil, fmt.Errorf("error creating temporary working directory for envoy: %w", err)
+	}
+
+	srv := &Server{
+		wd:       wd,
+		grpcPort: grpcPort,
+		httpPort: httpPort,
+	}
+
+	err = srv.writeConfig()
+	if err != nil {
+		return nil, fmt.Errorf("error writing initial envoy configuration: %w", err)
+	}
+
+	return srv, nil
+}
+
+// Run runs the server by extracting the embedded envoy and then executing it.
+func (srv *Server) Run(ctx context.Context) error {
+	envoyPath, err := extractEmbeddedEnvoy()
+	if err != nil {
+		log.Warn().Err(err).Send()
+		envoyPath = "envoy"
+	}
+
+	srv.cmd = exec.CommandContext(ctx, envoyPath,
+		"-c", configFileName,
+		"--log-level", log.Logger.GetLevel().String(),
+		"--log-format", "%l--%n--%v",
+		"--log-format-escaped",
+	)
+	srv.cmd.Dir = srv.wd
+
+	stderr, err := srv.cmd.StderrPipe()
+	if err != nil {
+		return fmt.Errorf("error creating stderr pipe for envoy: %w", err)
+	}
+	go srv.handleLogs(stderr)
+
+	stdout, err := srv.cmd.StdoutPipe()
+	if err != nil {
+		return fmt.Errorf("error creating stderr pipe for envoy: %w", err)
+	}
+	go srv.handleLogs(stdout)
+
+	// make sure envoy is killed if we're killed
+	srv.cmd.SysProcAttr = sysProcAttr
+	return srv.cmd.Run()
+}
+
+func (srv *Server) writeConfig() error {
+	return atomic.WriteFile(filepath.Join(srv.wd, configFileName), strings.NewReader(`
+node:
+  id: pomerium-envoy
+  cluster: pomerium-envoy
+
+admin:
+  access_log_path: /tmp/admin_access.log
+  address:
+    socket_address: { address: 127.0.0.1, port_value: 9901 }
+
+dynamic_resources:
+  cds_config:
+    ads: {}
+    resource_api_version: V3
+  lds_config:
+    ads: {}
+    resource_api_version: V3
+  ads_config:
+    api_type: GRPC
+    transport_api_version: V3
+    grpc_services:
+      - envoy_grpc:
+          cluster_name: pomerium-control-plane-grpc
+static_resources:
+  clusters:
+  - name: pomerium-control-plane-grpc
+    connect_timeout: { seconds: 5 }
+    type: STATIC
+    hosts:
+    - socket_address:
+        address: 127.0.0.1
+        port_value: `+srv.grpcPort+`
+    http2_protocol_options: {}
+`))
+}
+
+func (srv *Server) handleLogs(stdout io.ReadCloser) {
+	fileNameAndNumberRE := regexp.MustCompile(`^(\[[^:]+:[0-9]+\])\s(.*)$`)
+
+	s := bufio.NewScanner(stdout)
+	for s.Scan() {
+		ln := s.Text()
+
+		// format: level--name--message
+		// message is c-escaped
+
+		lvl := zerolog.TraceLevel
+		if pos := strings.Index(ln, "--"); pos >= 0 {
+			lvlstr := ln[:pos]
+			ln = ln[pos+2:]
+			if x, err := zerolog.ParseLevel(lvlstr); err == nil {
+				lvl = x
+			}
+		}
+
+		name := ""
+		if pos := strings.Index(ln, "--"); pos >= 0 {
+			name = ln[:pos]
+			ln = ln[pos+2:]
+		}
+
+		msg := fileNameAndNumberRE.ReplaceAllString(ln, "\"$2\"")
+		if s, err := strconv.Unquote(msg); err == nil {
+			msg = s
+		}
+
+		log.WithLevel(lvl).Str("service", "envoy").Str("name", name).Msg(msg)
+	}
+}