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Merged
jholdstock merged 2 commits into from
Jun 1, 2026
Merged

Don't pass around a pointer to service. #209

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a75d7f6
Don't pass around a pointer to service.
jholdstock May 26, 2026
a8e3485
Tidy up Mutex usage.
jholdstock May 27, 2026
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98 changes: 47 additions & 51 deletions service.go
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Original file line number Diff line number Diff line change
Expand Up @@ -67,10 +67,10 @@ type Service struct {
Router *http.ServeMux

// Data cached by the service, protected by a mutex.
sync.RWMutex
Vsps vspSet
WebInfo webInfo
PriceInfo priceInfo
Mutex sync.RWMutex
}

// NewService creates a new dcrwebapi service.
Expand All @@ -83,7 +83,6 @@ func NewService() *Service {
Timeout: time.Second * 10,
},
Router: http.NewServeMux(),
Mutex: sync.RWMutex{},

Vsps: vspSet{
"teststakepool.decred.org": Vsp{
Expand Down Expand Up @@ -152,12 +151,12 @@ func NewService() *Service {
// Start update ticker.
go func() {
for {
vspData(&service)
err := info(&service)
service.vspData()
err := service.info()
if err != nil {
log.Printf("Error updating web info: %v", err)
}
err = price(&service)
err = service.price()
if err != nil {
log.Printf("Error updating price info: %v", err)
}
Expand All @@ -172,14 +171,14 @@ func NewService() *Service {

// getHTTP will use the services HTTP client to send a GET request to the
// provided URL. Returns the response body, or an error.
func (service *Service) getHTTP(url string) ([]byte, error) {
func (s *Service) getHTTP(url string) ([]byte, error) {
req, err := http.NewRequest(http.MethodGet, url, nil)
if err != nil {
return nil, fmt.Errorf("%v: failed to create request: %w", url, err)
}

req.Header.Set("User-Agent", "decred/dcrweb bot")
poolResp, err := service.HTTPClient.Do(req)
poolResp, err := s.HTTPClient.Do(req)
if err != nil {
return nil, fmt.Errorf("%v: failed to send request: %w", url, err)
}
Expand All @@ -198,15 +197,10 @@ func (service *Service) getHTTP(url string) ([]byte, error) {
return respBody, nil
}

func vspStats(service *Service, url string) error {
var vsp Vsp

service.Mutex.RLock()
vsp = service.Vsps[url]
service.Mutex.RUnlock()
func (s *Service) vspStats(url string, vsp Vsp) error {
infoURL := fmt.Sprintf("https://%s/api/v3/vspinfo", url)

infoResp, err := service.getHTTP(infoURL)
infoResp, err := s.getHTTP(infoURL)
if err != nil {
return err
}
Expand All @@ -230,31 +224,33 @@ func vspStats(service *Service, url string) error {

vsp.LastUpdated = time.Now().Unix()

service.Mutex.Lock()
service.Vsps[url] = vsp
service.Mutex.Unlock()
s.Lock()
s.Vsps[url] = vsp
s.Unlock()

return nil
}

func vspData(service *Service) {
var waitGroup sync.WaitGroup
waitGroup.Add(len(service.Vsps))
for url := range service.Vsps {
go func(url string) {
defer waitGroup.Done()
err := vspStats(service, url)
func (s *Service) vspData() {
var wg sync.WaitGroup
s.RLock()
wg.Add(len(s.Vsps))
for url, vsp := range s.Vsps {
go func(url string, vsp Vsp) {
defer wg.Done()
err := s.vspStats(url, vsp)
if err != nil {
log.Println(err)
}
}(url)
}(url, vsp)
}
waitGroup.Wait()
s.RUnlock()
wg.Wait()
}

// dcrdata gets an API response from dcrdata and unmarshals it.
func (service *Service) dcrdata(path string, response interface{}) error {
body, err := service.getHTTP("https://dcrdata.decred.org/api" + path)
func (s *Service) dcrdata(path string, response interface{}) error {
body, err := s.getHTTP("https://dcrdata.decred.org/api" + path)
if err != nil {
return err
}
Expand All @@ -267,48 +263,48 @@ func (service *Service) dcrdata(path string, response interface{}) error {
return nil
}

func price(service *Service) error {
func (s *Service) price() error {
var exchange struct {
DcrPrice float64 `json:"dcrPrice"`
BtcPrice float64 `json:"btcPrice"`
}
err := service.dcrdata("/exchangerate", &exchange)
err := s.dcrdata("/exchangerate", &exchange)
if err != nil {
return err
}

service.Mutex.Lock()
service.PriceInfo = priceInfo{
s.Lock()
s.PriceInfo = priceInfo{
BitcoinUSD: exchange.BtcPrice,
DecredUSD: exchange.DcrPrice,
LastUpdated: time.Now().Unix(),
}
service.Mutex.Unlock()
s.Unlock()

return nil
}

func info(service *Service) error {
func (s *Service) info() error {
var supply apitypes.CoinSupply
err := service.dcrdata("/supply", &supply)
err := s.dcrdata("/supply", &supply)
if err != nil {
return err
}

var bestBlock apitypes.BlockDataBasic
err = service.dcrdata("/block/best", &bestBlock)
err = s.dcrdata("/block/best", &bestBlock)
if err != nil {
return err
}

var treasury dbtypes.TreasuryBalance
err = service.dcrdata("/treasury/balance", &treasury)
err = s.dcrdata("/treasury/balance", &treasury)
if err != nil {
return err
}

var subsidy apitypes.BlockSubsidies
err = service.dcrdata("/block/best/subsidy", &subsidy)
err = s.dcrdata("/block/best/subsidy", &subsidy)
if err != nil {
return err
}
Expand All @@ -318,8 +314,8 @@ func info(service *Service) error {
return dcrutil.Amount(atoms).ToCoin()
}

service.Mutex.Lock()
service.WebInfo = webInfo{
s.Lock()
s.WebInfo = webInfo{
Circulating: toDCR(supply.Mined),
Ultimate: toDCR(supply.Ultimate),
Staked: bestBlock.PoolInfo.Value,
Expand All @@ -329,20 +325,20 @@ func info(service *Service) error {
Height: bestBlock.Height,
LastUpdated: time.Now().Unix(),
}
service.Mutex.Unlock()
s.Unlock()

return nil
}

// HandleRoutes is the handler func for all endpoints exposed by the service
func (service *Service) HandleRoutes(writer http.ResponseWriter, request *http.Request) {
func (s *Service) HandleRoutes(writer http.ResponseWriter, request *http.Request) {
route := request.URL.Query().Get("c")
switch route {

case "vsp":
service.Mutex.RLock()
respJSON, err := json.Marshal(service.Vsps)
service.Mutex.RUnlock()
s.RLock()
respJSON, err := json.Marshal(s.Vsps)
s.RUnlock()
if err != nil {
writeJSONErrorResponse(&writer, err)
return
Expand All @@ -352,9 +348,9 @@ func (service *Service) HandleRoutes(writer http.ResponseWriter, request *http.R
return

case "webinfo":
service.Mutex.RLock()
respJSON, err := json.Marshal(service.WebInfo)
service.Mutex.RUnlock()
s.RLock()
respJSON, err := json.Marshal(s.WebInfo)
s.RUnlock()
if err != nil {
writeJSONErrorResponse(&writer, err)
return
Expand All @@ -364,9 +360,9 @@ func (service *Service) HandleRoutes(writer http.ResponseWriter, request *http.R
return

case "price":
service.Mutex.RLock()
respJSON, err := json.Marshal(service.PriceInfo)
service.Mutex.RUnlock()
s.RLock()
respJSON, err := json.Marshal(s.PriceInfo)
s.RUnlock()
if err != nil {
writeJSONErrorResponse(&writer, err)
return
Expand Down
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