// RunQuery is a function that is launched as a goroutine to perform
// the MongoDB work.
func RunQuery(query int, waitGroup *sync.WaitGroup, mongoSession *mgo.Session) {
// Decrement the wait group count so the program knows this
// has been completed once the goroutine exits.
defer waitGroup.Done()
// Request a socket connection from the session to process our query.
// Close the session when the goroutine exits and put the connection back
// into the pool.
sessionCopy := mongoSession.Copy()
defer sessionCopy.Close()
// Get a collection to execute the query against.
collection := sessionCopy.DB(TestDatabase).C("buoy_stations")
log.Printf("RunQuery : %d : Executing\n", query)
// Retrieve the list of stations.
var buoyStations []BuoyStation
err := collection.Find(nil).All(&buoyStations)
if err != nil {
log.Printf("RunQuery : ERROR : %s\n", err)
return
}
log.Printf("RunQuery : %d : Count[%d]\n", query, len(buoyStations))
}
/*
* makeHandler warps around handlers providing them with a session, and automatically closing that session
* to prevent loosing memory.
*/
func makeHandler(fn func(http.ResponseWriter, *http.Request, *mgo.Session), session *mgo.Session) http.HandlerFunc {
return func(w http.ResponseWriter, r *http.Request) {
s := session.Copy() // Create a copy of the session
fn(w, r, s)
s.Close() // Close the copy
}
}
func CopySession(s *mgo.Session) *mgo.Session {
for i := 0; i < CopySessionMaxRetry; i++ {
res := s.Copy()
err := checkSession(res)
if err == nil {
return res
}
CloseSession(res)
log.Print("[MGO2_COPY_SESSION] copy session and check failed:", err)
if isServersFailed(err) {
panic("[MGO2_COPY_SESSION_FAILED] servers failed")
}
}
msg := fmt.Sprintf("[MGO2_COPY_SESSION_FAILED] failed after %d retries", CopySessionMaxRetry)
log.Fatal(msg)
panic(msg)
}
func MakeTodoProducer(b *Broker, session *mgo.Session) RequestFunc {
return func(resp http.ResponseWriter, req *http.Request) {
ProduceTodos(resp, req, b, session.Copy())
}
}
func main() {
flag.Parse()
defer func() {
if err := recover(); err != nil {
panic(err)
}
}()
var session *mgo.Session
var err error
go func() {
for session == nil {
log.Println("Connecting to mongo..")
session, err = mgo.Dial(os.Getenv("CU_DB"))
if err != nil {
if session != nil {
session.Close()
session = nil
}
log.Printf("Database connection failed (%q), retrying..", err)
time.Sleep(10 * time.Second)
}
}
log.Println("Connected to mongo.")
}()
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
// Query boxes
splitted := strings.SplitN(r.URL.Path[1:], "/", 2)
if len(splitted) < 2 {
w.WriteHeader(http.StatusBadRequest)
return
}
if session == nil {
log.Printf("%v StatusServiceUnavailable session == nil", splitted[0])
w.WriteHeader(http.StatusServiceUnavailable)
return
}
validTokenQuery := bson.M{
"$and": []bson.M{
bson.M{"name": splitted[0]},
bson.M{"boxJSON.publish_token": splitted[1]}}}
err := ErrDbTimeout
var n int
done := make(chan struct{})
go func() {
this_session := session.Copy()
defer this_session.Close()
db := this_session.DB("")
n, err = db.C("boxes").Find(validTokenQuery).Count()
close(done)
}()
select {
case <-time.After(5 * time.Second):
case <-done:
}
if err != nil {
log.Printf("%v StatusServiceUnavailable %q", splitted[0], err)
w.WriteHeader(http.StatusServiceUnavailable)
return
}
if n == 0 {
log.Printf("%v StatusForbidden", splitted[0])
w.WriteHeader(http.StatusForbidden)
return
}
w.WriteHeader(http.StatusOK)
})
println("Listening...")
err = http.ListenAndServe(":23423", nil)
check(err)
}
func FastCopySession(s *mgo.Session) *mgo.Session {
return s.Copy()
}