Fix start problem with two IronFunction colliding configurations

By default, BoltDB will hang while waiting to acquire lock to the
datafile, thus the users might find themselves waiting for something
but not what. The added timeout aims inform use about what's
happening.

Also this renames MQADR to TASKSRV, refactor configuration to read
environment variables. RunAsyncRunner now fills the gaps when
parsing TASKSRV.

Fixes #119

api/runner/async_runner.go

@@ -4,16 +4,15 @@ import (
 	"bytes"
 	"encoding/json"
 	"errors"
-	"fmt"
 	"io/ioutil"
+	"net"
 	"net/http"
+	"net/url"
 	"time"
 
-	"golang.org/x/net/context"
-
 	log "github.com/Sirupsen/logrus"
-
 	"github.com/iron-io/functions/api/models"
+	"golang.org/x/net/context"
 )
 
 func getTask(url string) (*models.Task, error) {
@@ -96,10 +95,10 @@ func runTask(task *models.Task) error {
 }
 
 // RunAsyncRunner pulls tasks off a queue and processes them
-func RunAsyncRunner(mqAdr string) {
-	url := fmt.Sprintf("http://%s/tasks", mqAdr)
+func RunAsyncRunner(tasksrv, port string) {
+	u := tasksrvURL(tasksrv, port)
 	for {
-		task, err := getTask(url)
+		task, err := getTask(u)
 		if err != nil {
 			log.WithError(err)
 			time.Sleep(1 * time.Second)
@@ -115,10 +114,31 @@ func RunAsyncRunner(mqAdr string) {
 		log.Info("Processed task:", task.ID)
 
 		// Delete task from queue
-		if err := deleteTask(url, task); err != nil {
+		if err := deleteTask(u, task); err != nil {
 			log.WithError(err)
 		} else {
 			log.Info("Deleted task:", task.ID)
 		}
 	}
 }
+
+func tasksrvURL(tasksrv, port string) string {
+	parsed, err := url.Parse(tasksrv)
+	if err != nil {
+		log.Fatalf("cannot parse TASKSRV endpoint: %v", err)
+	}
+
+	if parsed.Scheme == "" {
+		parsed.Scheme = "http"
+	}
+
+	if parsed.Path == "" || parsed.Path == "/" {
+		parsed.Path = "/tasks"
+	}
+
+	if _, _, err := net.SplitHostPort(parsed.Host); err != nil {
+		parsed.Host = net.JoinHostPort(parsed.Host, port)
+	}
+
+	return parsed.String()
+}