123 lines
2.6 KiB
Go
123 lines
2.6 KiB
Go
package main
|
|
|
|
import (
|
|
"asink"
|
|
"bytes"
|
|
"encoding/json"
|
|
"errors"
|
|
"fmt"
|
|
"io/ioutil"
|
|
"net/http"
|
|
"strconv"
|
|
"time"
|
|
)
|
|
|
|
const MIN_ERROR_WAIT = 100 // 1/10 of a second
|
|
const MAX_ERROR_WAIT = 10000 // 10 seconds
|
|
|
|
func SendEvent(globals AsinkGlobals, event *asink.Event) error {
|
|
url := "http://" + globals.server + ":" + strconv.Itoa(int(globals.port)) + "/events/"
|
|
|
|
//construct json payload
|
|
events := asink.EventList{
|
|
Events: []*asink.Event{event},
|
|
}
|
|
b, err := json.Marshal(events)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
fmt.Println(string(b))
|
|
|
|
//actually make the request
|
|
resp, err := http.Post(url, "application/json", bytes.NewReader(b))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer resp.Body.Close()
|
|
|
|
//check to make sure request succeeded
|
|
body, err := ioutil.ReadAll(resp.Body)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
var apistatus asink.APIResponse
|
|
err = json.Unmarshal(body, &apistatus)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
if apistatus.Status != asink.SUCCESS {
|
|
return errors.New("API response was not success: " + apistatus.Explanation)
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func GetEvents(globals AsinkGlobals, events chan *asink.Event) {
|
|
url := "http://" + globals.server + ":" + strconv.Itoa(int(globals.port)) + "/events/"
|
|
var successiveErrors uint = 0
|
|
|
|
errorWait := func(err error) {
|
|
fmt.Println(err)
|
|
var waitMilliseconds time.Duration = MIN_ERROR_WAIT << successiveErrors
|
|
if waitMilliseconds > MAX_ERROR_WAIT {
|
|
waitMilliseconds = MAX_ERROR_WAIT
|
|
}
|
|
time.Sleep(waitMilliseconds * time.Millisecond)
|
|
successiveErrors++
|
|
}
|
|
|
|
//query DB for latest remote event version number that we've seen locally
|
|
latestEvent, err := globals.db.DatabaseLatestRemoteEvent()
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
|
|
for {
|
|
//query for events after latest_event
|
|
var fullUrl string
|
|
if latestEvent != nil {
|
|
fullUrl = url + strconv.FormatInt(latestEvent.Id+1, 10)
|
|
} else {
|
|
fullUrl = url + "0"
|
|
}
|
|
resp, err := http.Get(fullUrl)
|
|
|
|
//if error, perform exponential backoff (with maximum timeout)
|
|
if err != nil {
|
|
if resp != nil {
|
|
resp.Body.Close()
|
|
}
|
|
errorWait(err)
|
|
continue
|
|
}
|
|
|
|
body, err := ioutil.ReadAll(resp.Body)
|
|
resp.Body.Close() //must be done after the last time resp is used
|
|
if err != nil {
|
|
errorWait(err)
|
|
continue
|
|
}
|
|
|
|
var apistatus asink.APIResponse
|
|
err = json.Unmarshal(body, &apistatus)
|
|
if err != nil {
|
|
errorWait(err)
|
|
continue
|
|
}
|
|
if apistatus.Status != asink.SUCCESS {
|
|
errorWait(err)
|
|
continue
|
|
}
|
|
|
|
for _, event := range apistatus.Events {
|
|
if latestEvent != nil && event.Id != latestEvent.Id+1 {
|
|
break
|
|
}
|
|
events <- event
|
|
latestEvent = event
|
|
}
|
|
successiveErrors = 0
|
|
}
|
|
}
|