Create gopkgs directory for golang libs

- Created a gopkgs directory and registered it with default.nix's readTree
- Moved monzo_ynab/utils -> gopkgs
- Consumed utils.go in main.go
- Renamed monzo_ynab -> job

gopkgs/utils/utils.go

@@ -0,0 +1,56 @@
+// Some utility functions to tidy up my Golang.
+package utils
+
+import (
+	"log"
+	"io/ioutil"
+	"net/http"
+	"net/http/httputil"
+)
+
+// Call log.Fatal with `err` when it's not nil.
+func FailOn(err error) {
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
+// Make a simple GET request to `url`. Fail if anything returns an error. I'd
+// like to accumulate a library of these, so that I can write scrappy Go
+// quickly. For now, this function just returns the body of the response back as
+// a string.
+func SimpleGet(url string, headers map[string]string, debug bool) string {
+	client := &http.Client{}
+	req, err := http.NewRequest("GET", url, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	for k, v := range headers {
+		req.Header.Add(k, v)
+	}
+
+	res, err := client.Do(req)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer res.Body.Close()
+
+	if debug {
+		bytes, _ := httputil.DumpRequest(req, true)
+		log.Println(string(bytes))
+		bytes, _ = httputil.DumpResponse(res, true)
+		log.Println(string(bytes))
+	}
+
+	if res.StatusCode == http.StatusOK {
+		bytes, err := ioutil.ReadAll(res.Body)
+		if err != nil {
+			log.Fatal(err)
+		}
+		return string(bytes)
+	} else {
+		log.Println(res)
+		log.Fatalf("HTTP status code of response not OK: %v\n", res.StatusCode)
+		return ""
+	}
+}