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app.go
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app.go
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package app
import (
"context"
"crypto/tls"
"net"
"net/http"
"reflect"
"sync"
"github.com/consensys/quorum-key-manager/src/infra/log"
"github.com/consensys/quorum-key-manager/pkg/common"
"github.com/consensys/quorum-key-manager/pkg/errors"
"github.com/consensys/quorum-key-manager/pkg/http/server"
gorillamux "github.com/gorilla/mux"
)
const (
initializingState = iota
runningState
stoppingState
closedState
pointerErrMessage = "cannot attach service to a non pointer"
)
// App is the main Key Manager application object
type App struct {
cfg *Config
// logger logger object
logger log.Logger
// server processing HTTP(s) requests
server *http.Server
healthz *http.Server
router *gorillamux.Router
// middleware applied before routing
middleware func(http.Handler) http.Handler
// Services attached to the app
mux sync.Mutex
services []reflect.Value
serviceConfigs map[reflect.Type]reflect.Value
state int // tracks state of app
errors chan error
}
func New(cfg *Config, logger log.Logger) *App {
// Create router and register APIs
router := gorillamux.NewRouter()
// Create API server
apiServer := server.New(cfg.HTTP)
apiServer.Handler = router
// Create Healthz server
healthzServer := server.NewHealthz(cfg.HTTP)
healthzServer.Handler = server.NewHealthzHandler()
return &App{
cfg: cfg,
logger: logger,
server: apiServer,
healthz: healthzServer,
errors: make(chan error),
router: router,
serviceConfigs: make(map[reflect.Type]reflect.Value),
}
}
func (app *App) SetMiddleware(mid func(http.Handler) http.Handler) error {
app.mux.Lock()
defer app.mux.Unlock()
if app.state != initializingState {
errMessage := "can't register middleware on running or stopped app"
app.logger.Error(errMessage)
return errors.ConfigError(errMessage)
}
app.middleware = mid
return nil
}
// RegisterServiceConfig register a config
// cfg MUST be a pointer to a struct
func (app *App) RegisterServiceConfig(cfg interface{}) error {
app.mux.Lock()
defer app.mux.Unlock()
if app.state != initializingState {
errMessage := "can't register config on running or stopped app"
app.logger.Error(errMessage)
return errors.ConfigError(errMessage)
}
if app.hasConfig(cfg) {
errMessage := "attempt to register config %T more than once"
app.logger.Error(errMessage)
return errors.ConfigError(errMessage)
}
cfgV := reflect.ValueOf(cfg)
if !(cfgV.IsValid() && cfgV.Type().Kind() == reflect.Ptr && cfgV.Type().Elem().Kind() == reflect.Struct) {
errMessage := "failed to extract config"
app.logger.Error(errMessage, "config", cfg)
return errors.ConfigError(errMessage)
}
app.serviceConfigs[cfgV.Type()] = cfgV
return nil
}
func (app *App) hasConfig(i interface{}) bool {
if _, ok := app.serviceConfigs[reflect.TypeOf(i)]; ok {
return true
}
return false
}
// ServiceConfig loads a service configuration into cfg
// It expects a pointer to a struct and then sets its value
func (app *App) ServiceConfig(cfg interface{}) error {
app.mux.Lock()
defer app.mux.Unlock()
cfgV := reflect.ValueOf(cfg)
if cfgV.Type().Kind() != reflect.Ptr {
app.logger.Error(pointerErrMessage)
return errors.ConfigError(pointerErrMessage)
}
for typ, config := range app.serviceConfigs {
if typ == cfgV.Type() {
if !config.IsZero() {
cfgV.Elem().Set(config.Elem())
}
return nil
}
}
return errors.ConfigError("unknown config")
}
func (app *App) RegisterService(srv interface{}) error {
app.mux.Lock()
defer app.mux.Unlock()
if app.state != initializingState {
errMessage := "cannot register service on running or stopped app"
app.logger.Error(errMessage)
return errors.ConfigError(errMessage)
}
if rSrv, ok := srv.(common.Runnable); ok {
app.services = append(app.services, reflect.ValueOf(rSrv))
} else {
errMessage := "registered service is not a runnable"
app.logger.Error(errMessage)
return errors.ConfigError(errMessage)
}
if hlzSrv, ok := srv.(common.Checkable); ok {
if healthz, ok2 := app.healthz.Handler.(*server.HealthzHandler); ok2 {
healthz.AddLivenessCheck(hlzSrv.ID(), hlzSrv.CheckLiveness)
healthz.AddReadinessCheck(hlzSrv.ID(), hlzSrv.CheckReadiness)
}
}
return nil
}
// Service loads a service into srv
// It expects a pointer and then sets its value
func (app *App) Service(srv interface{}) error {
app.mux.Lock()
defer app.mux.Unlock()
// Finds the service to return
srvV := reflect.ValueOf(srv)
if srvV.Type().Kind() != reflect.Ptr {
app.logger.Error(pointerErrMessage)
return errors.ConfigError(pointerErrMessage)
}
for _, regSrv := range app.services {
typ := regSrv.Type()
switch {
case typ == srvV.Type():
srvV.Elem().Set(regSrv.Elem())
return nil
case typ == srvV.Type().Elem():
srvV.Elem().Set(regSrv)
return nil
case srvV.Elem().Type().Kind() == reflect.Interface && typ.Implements(srvV.Elem().Type()):
srvV.Elem().Set(regSrv)
return nil
}
}
return errors.ConfigError("unknown service")
}
func (app *App) Router() *gorillamux.Router {
return app.router
}
func (app *App) startServer() {
app.logger.Debug("starting app server...")
// Wrap handler into middleware
if app.middleware != nil {
app.server.Handler = app.middleware(app.server.Handler)
}
go func() {
ln, err := net.Listen("tcp", app.server.Addr)
if err != nil {
app.logger.WithError(err).Info("failed to start API server")
app.errors <- err
}
var apiErr error
if app.cfg.HTTP.TLSConfig != nil {
tlsListener := tls.NewListener(ln, app.cfg.HTTP.TLSConfig)
app.logger.Info("API SSL server started ", "addr", app.server.Addr)
apiErr = app.server.Serve(tlsListener)
} else {
app.logger.Info("API server started", "addr", app.server.Addr)
apiErr = app.server.Serve(ln)
}
if apiErr != nil && apiErr != context.Canceled && apiErr != http.ErrServerClosed {
app.logger.Debug("API server exited gracefully", "addr", app.server.Addr)
} else {
app.logger.WithError(apiErr).Error("API server exited with errors")
app.errors <- apiErr
}
}()
go func() {
ln, err := net.Listen("tcp", app.healthz.Addr)
if err != nil {
app.logger.WithError(err).Info("failed to start Health server")
app.errors <- err
}
var healthErr error
if app.cfg.HTTP.TLSConfig != nil {
tlsListener := tls.NewListener(ln, app.cfg.HTTP.TLSConfig)
app.logger.Info("Health SSL server started ", "addr", app.healthz.Addr)
healthErr = app.healthz.Serve(tlsListener)
} else {
app.logger.Info("Health server started", "addr", app.healthz.Addr)
healthErr = app.healthz.Serve(ln)
}
if healthErr != nil && healthErr != context.Canceled && healthErr != http.ErrServerClosed {
app.logger.Debug("Health server exited gracefully", "addr", app.server.Addr)
} else {
app.logger.WithError(healthErr).Error("Health server exited with errors")
app.errors <- healthErr
}
}()
app.logger.Debug("servers (API and Health) have started")
}
func (app *App) stopServer(ctx context.Context) error {
app.logger.Debug("shutting down app server...")
if err := app.healthz.Shutdown(ctx); err != nil {
app.logger.WithError(err).Error("health server could not shut down")
return err
}
if err := app.server.Shutdown(ctx); err != nil {
app.logger.WithError(err).Error("http api server could not shut down")
return err
}
app.logger.Info("servers (API and Health) gracefully shut down")
return nil
}
func (app *App) closeServer() error {
return app.server.Close()
}
func (app *App) Start(ctx context.Context) error {
app.logger.Debug("starting application...")
app.state = runningState
app.startServer()
// Start all registered services.
var err error
var started []common.Runnable
for i := len(app.services) - 1; i >= 0; i-- {
srv := app.services[i].Interface().(common.Runnable)
if err = srv.Start(ctx); err != nil {
break
}
started = append(started, srv)
}
// If a service failed to start then stop other services
if err != nil {
app.state = stoppingState
for i := len(started) - 1; i >= 0; i-- {
_ = started[i].Stop(ctx)
}
_ = app.stopServer(ctx)
}
app.logger.Info("application started")
return err
}
func (app *App) Stop(ctx context.Context) error {
app.logger.Debug("stopping application...")
app.state = stoppingState
var err error
for i := len(app.services) - 1; i >= 0; i-- {
srv := app.services[i].Interface().(common.Runnable)
if srvErr := srv.Stop(ctx); srvErr != nil {
err = srvErr
}
}
httpErr := app.stopServer(ctx)
if httpErr != nil {
err = httpErr
}
app.logger.Info("application stopped")
return err
}
func (app *App) Errors() <-chan error {
return app.errors
}
func (app *App) Close() error {
app.state = closedState
close(app.errors)
return app.closeServer()
}