Add gosh: run Go as a shell scripting language

home/bin/SimpleHTTPServer

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+#!/usr/bin/env gosh
+package main
+
+// SimpleHTTPServer is a simple Go static file server, similar to the Python
+// module of the same name, but which supports high concurrency and all the
+// other niceties that you get from Go out of the box.
+//
+// It runs via my `gosh` wrapper for treating simple Go programs as shell
+// scripts. See my `gosh` script, or just remove the shebang line at the top
+// of this file to `go build` your own version.
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+)
+
+// LogMiddleware logs all HTTP requests.
+func LogMiddleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		res := &ResponseWriter{w, 200}
+		next.ServeHTTP(res, r)
+		log.Printf("%s %d %s %s\n",
+			r.RemoteAddr,
+			res.Status,
+			r.Method,
+			r.RequestURI,
+		)
+	})
+}
+
+// ResponseWriter is my own wrapper around http.ResponseWriter that lets me
+// capture its status code, for logging purposes.
+type ResponseWriter struct {
+	http.ResponseWriter
+	Status int
+}
+
+// WriteHeader wraps http.WriteHeader to also capture the status code.
+func (w *ResponseWriter) WriteHeader(code int) {
+	w.ResponseWriter.WriteHeader(code)
+	w.Status = code
+}
+
+func main() {
+	// Command line flag: the port number to listen on.
+	port := flag.Int("port", 8000, "The port number to listen on.")
+	flag.Parse()
+
+	fmt.Printf("Serving at http://0.0.0.0:%d/\n", *port)
+	err := http.ListenAndServe(
+		fmt.Sprintf(":%d", *port),
+		LogMiddleware(http.FileServer(http.Dir("."))),
+	)
+	panic(err)
+}

home/bin/gosh

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+#!/usr/bin/env python
+
+"""gosh: use Golang as a shell scripting language.
+
+This is written in Python so that I don't have to commit any binaries to my
+dotfiles repo, and my Go shell scripts can also remain in source form.
+
+Usage: write a Go program with this shebang comment on top immediately before
+the `package main` statement:
+
+    #!/usr/bin/env gosh
+    package main
+
+And make it executable and run it like any shell script.
+"""
+
+import codecs
+import os
+import subprocess
+import sys
+import tempfile
+
+def main():
+    if len(sys.argv) == 1:
+        die("Usage: gosh <file.go>")
+
+    # Get the Go source file from the command line.
+    source = sys.argv[1]
+    argv   = sys.argv[2:]
+    if not os.path.isfile(source):
+        die("{}: not a file".format(source))
+
+    # Make a temp file that lacks the shebang line of the input file.
+    with codecs.open(source, "r", "utf-8") as fh:
+        # Get the shebang off and sanity check it.
+        shebang = fh.readline()
+        if not "gosh" in shebang:
+            die("{}: doesn't appear to be a Go script".format(source))
+
+        # Write it to a temp file, sans shebang.
+        temp = tempfile.NamedTemporaryFile(delete=False, suffix=".go")
+        temp.write(fh.read().strip())
+        temp.close()
+
+        # Call it.
+        subprocess.call(["go", "run", temp.name] + argv)
+
+        # Clean up.
+        os.unlink(temp.name)
+
+def die(message):
+    print(message)
+    sys.exit(1)
+
+if __name__ == "__main__":
+    main()