Retrieve function logs from controller (#207)

Establish a proxy server from the controller to the log database.

Redirect query commands send from client to database then proxy back the db response.

Use parameter binding instead of fmt.Sprintf to prevent SQL injection.

controller/api.go

@@ -21,21 +21,31 @@ import (
 	"net/http"
 	"os"
 	"runtime/debug"
+	"strings"
 
 	log "github.com/Sirupsen/logrus"
 	"github.com/gorilla/handlers"
 	"github.com/gorilla/mux"
 
 	"github.com/fission/fission"
+	"github.com/fission/fission/fission/logdb"
 )
 
-type API struct {
-	FunctionStore
-	HTTPTriggerStore
-	TimeTriggerStore
-	EnvironmentStore
-	WatchStore
-}
+type (
+	API struct {
+		FunctionStore
+		HTTPTriggerStore
+		TimeTriggerStore
+		EnvironmentStore
+		WatchStore
+	}
+
+	logDBConfig struct {
+		httpURL  string
+		username string
+		password string
+	}
+)
 
 func MakeAPI(rs *ResourceStore) *API {
 	api := &API{
@@ -64,6 +74,23 @@ func (api *API) respondWithError(w http.ResponseWriter, err error) {
 	http.Error(w, msg, code)
 }
 
+func (api *API) getLogDBConfig(dbType string) logDBConfig {
+	dbType = strings.ToUpper(dbType)
+	// retrieve db auth config from the env
+	url := os.Getenv(fmt.Sprintf("%s_URL", dbType))
+	if url == "" {
+		// set up default database url
+		url = logdb.INFLUXDB_URL
+	}
+	username := os.Getenv(fmt.Sprintf("%s_USERNAME", dbType))
+	password := os.Getenv(fmt.Sprintf("%s_PASSWORD", dbType))
+	return logDBConfig{
+		httpURL:  url,
+		username: username,
+		password: password,
+	}
+}
+
 func (api *API) HomeHandler(w http.ResponseWriter, r *http.Request) {
 	w.Header().Set("Content-Type", "application/json; charset=utf-8")
 	fmt.Fprintf(w, "{\"message\": \"Fission API\", \"version\": \"0.1.0\"}\n")
@@ -103,6 +130,8 @@ func (api *API) Serve(port int) {
 	r.HandleFunc("/v1/triggers/time/{timeTrigger}", api.TimeTriggerApiUpdate).Methods("PUT")
 	r.HandleFunc("/v1/triggers/time/{timeTrigger}", api.TimeTriggerApiDelete).Methods("DELETE")
 
+	r.HandleFunc("/proxy/{dbType}", api.FunctionLogsApiPost).Methods("POST")
+
 	address := fmt.Sprintf(":%v", port)
 
 	log.WithFields(log.Fields{"port": port}).Info("Server started")