blog: add asarfs post

blog/crazy-experiment-2017-01-09.markdown

@@ -0,0 +1,59 @@
+---
+title: "Crazy Experiment: Frontend Shipping as asar"
+date: "2017-01-09"
+---
+
+Today's crazy experiment is using an [asar archive](https://github.com/electron/asar) for shipping around
+and mounting frontend Javascript applications. This is something I feel is worth doing because it allows
+the web frontend developer (or team) give the backend team a single "binary" that can be dropped into the
+deployment process without having to build the frontend code as part of CI.
+
+asar is an interesting file format because it allows for random access of the data inside the archive.
+This allows an HTTP server to be able to concurrently serve files out of it without having to lock or
+incur an additional open file descriptor.
+
+In order to implement this, I have created a Go package named [asarfs](https://github.com/Xe/asarfs) that
+exposes the contents of an asar archive as a standard http.Handler.
+
+Example Usage:
+
+```go
+package main
+
+import (
+	"log"
+	"net/http"
+	"os"
+
+	"github.com/Xe/asarfs"
+)
+
+func do404(w http.ResponseWriter, r *http.Request) {
+	http.Error(w, "Not found", http.StatusNotFound)
+}
+
+func main() {
+	fs, err := asarfs.New("./static.asar", http.HandlerFunc(do404))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	http.ListenAndServe(":"+os.Getenv("PORT"), fs)
+}
+```
+
+I made some contrived benchmarks using some sample data (lots of large json files from mongodb dumps)
+I had laying around and ran them a few times. The results were very promising:
+
+```console
+[~/g/s/g/X/asarfs] : go1.8beta2 test -bench=. -benchmem
+BenchmarkHTTPFileSystem-8          20000             66481 ns/op            3219 B/op         58 allocs/op
+BenchmarkASARfs-8                  20000             72084 ns/op            3549 B/op         77 allocs/op
+BenchmarkPreloadedASARfs-8         20000             62894 ns/op            3218 B/op         58 allocs/op
+PASS
+ok      github.com/Xe/asarfs    5.636s
+```
+
+Amazingly, the performance and memory usage differences between serving the files over an asar archive
+and off of the filesystem are negligible. I've implemented it in the latest release of my personal website
+and hopefully end users should be seeing no difference in page load times.