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package cgi
import (
"context"
"fmt"
"io/ioutil"
"net"
"net/http"
"net/http/cgi"
"os"
"sync"
"time"
"git.capotej.com/capotej/communique/config"
"git.capotej.com/capotej/communique/models"
"github.com/mmcdole/gofeed"
"go.uber.org/zap"
)
type Servers struct {
log *zap.SugaredLogger
persister *models.Persister
}
func NewServers(log *zap.SugaredLogger, persister *models.Persister) *Servers {
return &Servers{log: log, persister: persister}
}
// Start iterates over all Handlers and starts an internal CGI server for each one
// along with ticker for the configured handler interval then blocks indefinitely
func (s *Servers) Start(cfg config.Config) {
var wg sync.WaitGroup
logger := s.log.With("type", "cgi")
for _, handler := range cfg.Handlers {
handlerLogger := logger.With("handler", handler.Name)
wg.Add(3)
// Internal CGI server
go func(aHandler config.Handler) {
defer wg.Done()
startCGIServer(aHandler, handlerLogger)
}(handler)
// Ticker
go func(aHandler config.Handler) {
defer wg.Done()
startTicker(aHandler, s.persister, handlerLogger)
}(handler)
// Execute a handler tick on start since Go's ticker waits until $interval to trigger first tick
go func(aHandler config.Handler) {
defer wg.Done()
time.Sleep(1 * time.Second)
output := tick(aHandler, handlerLogger)
err := processTick(aHandler, output, s.persister, handlerLogger)
if err != nil {
s.log.Error(err)
}
}(handler)
}
wg.Wait()
}
func startCGIServer(h config.Handler, log *zap.SugaredLogger) {
cgiHandler := cgi.Handler{Path: h.Exec}
server := http.Server{
Handler: &cgiHandler,
}
sock := fmt.Sprintf("%s.sock", h.Name)
log.Debugf("starting cgi server at %s", sock)
os.Remove(sock)
unixListener, err := net.Listen("unix", sock)
if err != nil {
panic(err)
}
server.Serve(unixListener)
}
func startTicker(h config.Handler, persister *models.Persister, log *zap.SugaredLogger) {
ticker := time.NewTicker(h.Interval) // TODO add some random jitter here so handlers dont run at the same exact intervals
done := make(chan bool)
func() {
for {
select {
case <-done:
return
case _ = <-ticker.C:
output := tick(h, log)
err := processTick(h, output, persister, log)
if err != nil {
log.Error(err)
}
}
}
}()
}
func processTick(h config.Handler, output []byte, persister *models.Persister, log *zap.SugaredLogger) error {
fp := gofeed.NewParser()
fp.ParseString(string(output))
feed, err := fp.ParseString(string(output))
if err != nil {
return err
}
for _, v := range feed.Items {
var extractedContent string
// if there is no content, use descrption
if len(v.Content) != 0 {
extractedContent = v.Content
} else if len(v.Description) != 0 {
extractedContent = v.Description
}
if len(extractedContent) != 0 {
log.Debugf("extracted content '%s'", extractedContent)
outboxItem := models.CreateOutboxItem(h, []byte(extractedContent))
err = persister.StoreWithCallback(outboxItem, func() {
logger := log.With("handler", h.Name).With("type", "subscription")
// go through handler subscriptions and deliver signed outbox items
logger.Debug("callback for save")
sub := models.NewSubscription(h)
keys, err := persister.CollectKeys(sub)
if err != nil {
logger.Error(err)
return
}
for _, v := range keys {
logger.Debugf("found subscription %s", string(v))
}
})
if err != nil {
return err
}
}
}
return nil
}
func tick(h config.Handler, log *zap.SugaredLogger) []byte {
sock := fmt.Sprintf("%s.sock", h.Name)
httpc := http.Client{
Transport: &http.Transport{
DialContext: func(_ context.Context, _, _ string) (net.Conn, error) {
return net.Dial("unix", sock)
},
},
}
var response *http.Response
var err error
log.Debugf("executing cgi handler at %s", sock)
response, err = httpc.Get("http://unix/" + sock)
if err != nil {
log.Errorf("received error from cgi handler %s", err)
}
body, err := ioutil.ReadAll(response.Body)
response.Body.Close()
return body
}
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