feat(pprof): add pprof HTTP server (#807)

- `PPROF_ENABLED=no`
- `PPROF_BLOCK_PROFILE_RATE=0`
- `PPROF_MUTEX_PROFILE_RATE=0`
- `PPROF_HTTP_SERVER_ADDRESS=":6060"`

internal/httpserver/server.go

@@ -0,0 +1,57 @@
+// Package httpserver implements an HTTP server.
+package httpserver
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"time"
+)
+
+var _ Interface = (*Server)(nil)
+
+// Interface is the HTTP server composite interface.
+type Interface interface {
+	Runner
+	AddressGetter
+}
+
+// Runner is the interface for an HTTP server with a Run method.
+type Runner interface {
+	Run(ctx context.Context, ready chan<- struct{}, done chan<- struct{})
+}
+
+// AddressGetter obtains the address the HTTP server is listening on.
+type AddressGetter interface {
+	GetAddress() (address string)
+}
+
+// Server is an HTTP server implementation, which uses
+// the HTTP handler provided.
+type Server struct {
+	name            string
+	address         string
+	addressSet      chan struct{}
+	handler         http.Handler
+	logger          Logger
+	shutdownTimeout time.Duration
+}
+
+// New creates a new HTTP server with the given settings.
+// It returns an error if one of the settings is not valid.
+func New(settings Settings) (s *Server, err error) {
+	settings.SetDefaults()
+
+	if err = settings.Validate(); err != nil {
+		return nil, fmt.Errorf("http server settings validation failed: %w", err)
+	}
+
+	return &Server{
+		name:            *settings.Name,
+		address:         settings.Address,
+		addressSet:      make(chan struct{}),
+		handler:         settings.Handler,
+		logger:          settings.Logger,
+		shutdownTimeout: *settings.ShutdownTimeout,
+	}, nil
+}