tusd/metrics.go

138 lines
3.6 KiB
Go

package tusd
import (
"errors"
"sync"
"sync/atomic"
)
// Metrics provides numbers about the usage of the tusd handler. Since these may
// be accessed from multiple goroutines, it is necessary to read and modify them
// atomically using the functions exposed in the sync/atomic package, such as
// atomic.LoadUint64. In addition the maps must not be modified to prevent data
// races.
type Metrics struct {
// RequestTotal counts the number of incoming requests per method
RequestsTotal map[string]*uint64
// ErrorsTotal counts the number of returned errors by their message
ErrorsTotal *ErrorsTotalMap
BytesReceived *uint64
UploadsFinished *uint64
UploadsCreated *uint64
UploadsTerminated *uint64
}
// incRequestsTotal increases the counter for this request method atomically by
// one. The method must be one of GET, HEAD, POST, PATCH, DELETE.
func (m Metrics) incRequestsTotal(method string) {
if ptr, ok := m.RequestsTotal[method]; ok {
atomic.AddUint64(ptr, 1)
}
}
// incErrorsTotal increases the counter for this error atomically by one.
func (m Metrics) incErrorsTotal(err HTTPError) {
ptr := m.ErrorsTotal.retrievePointerFor(err)
atomic.AddUint64(ptr, 1)
}
// incBytesReceived increases the number of received bytes atomically be the
// specified number.
func (m Metrics) incBytesReceived(delta uint64) {
atomic.AddUint64(m.BytesReceived, delta)
}
// incUploadsFinished increases the counter for finished uploads atomically by one.
func (m Metrics) incUploadsFinished() {
atomic.AddUint64(m.UploadsFinished, 1)
}
// incUploadsCreated increases the counter for completed uploads atomically by one.
func (m Metrics) incUploadsCreated() {
atomic.AddUint64(m.UploadsCreated, 1)
}
// incUploadsTerminated increases the counter for completed uploads atomically by one.
func (m Metrics) incUploadsTerminated() {
atomic.AddUint64(m.UploadsTerminated, 1)
}
func newMetrics() Metrics {
return Metrics{
RequestsTotal: map[string]*uint64{
"GET": new(uint64),
"HEAD": new(uint64),
"POST": new(uint64),
"PATCH": new(uint64),
"DELETE": new(uint64),
"OPTIONS": new(uint64),
},
ErrorsTotal: newErrorsTotalMap(),
BytesReceived: new(uint64),
UploadsFinished: new(uint64),
UploadsCreated: new(uint64),
UploadsTerminated: new(uint64),
}
}
// ErrorsTotalMap stores the counters for the different HTTP errors.
type ErrorsTotalMap struct {
lock sync.RWMutex
counter map[simpleHTTPError]*uint64
}
type simpleHTTPError struct {
Message string
StatusCode int
}
func simplifyHTTPError(err HTTPError) simpleHTTPError {
return simpleHTTPError{
Message: err.Error(),
StatusCode: err.StatusCode(),
}
}
func newErrorsTotalMap() *ErrorsTotalMap {
m := make(map[simpleHTTPError]*uint64, 20)
return &ErrorsTotalMap{
counter: m,
}
}
// retrievePointerFor returns (after creating it if necessary) the pointer to
// the counter for the error.
func (e *ErrorsTotalMap) retrievePointerFor(err HTTPError) *uint64 {
serr := simplifyHTTPError(err)
e.lock.RLock()
ptr, ok := e.counter[serr]
e.lock.RUnlock()
if ok {
return ptr
}
// For pointer creation, a write-lock is required
e.lock.Lock()
// We ensure that the pointer wasn't created in the meantime
if ptr, ok = e.counter[serr]; !ok {
ptr = new(uint64)
e.counter[serr] = ptr
}
e.lock.Unlock()
return ptr
}
// Load retrieves the map of the counter pointers atomically
func (e *ErrorsTotalMap) Load() map[HTTPError]*uint64 {
m := make(map[HTTPError]*uint64, len(e.counter))
e.lock.RLock()
for err, ptr := range e.counter {
httpErr := NewHTTPError(errors.New(err.Message), err.StatusCode)
m[httpErr] = ptr
}
e.lock.RUnlock()
return m
}