feat: fill in Go developer journey (#290)

user_stories/go

@@ -3,6 +3,47 @@
 # with the Go language enabled.
 set -o errexit -o pipefail -o nounset
 
-# Create/update the go.mod file
+# The user writes some Go code with external imports
+# Maybe they just search for "golang hello world"
+# and paste the code found at https://yourbasic.org/golang/http-server-example/
+# And then they also add an external dependency on 
+# https://pkg.go.dev/nmyk.io/cowsay just for fun.
+mkdir -p cmd/hello
+cat >cmd/hello/main.go <<EOF
+package main
+
+import (
+    "net/http"
+    "nmyk.io/cowsay"
+)
+
+func main() {
+    http.HandleFunc("/", HelloServer)
+    http.ListenAndServe(":8080", nil)
+}
+
+func HelloServer(w http.ResponseWriter, r *http.Request) {
+    cowsay.Cow{}.Write(w, []byte("Hello, world!"), false)
+}
+EOF
+
+# Create/update the go.mod file, including the nmyk.io/cowsay dependency pinning
 ./tools/go mod tidy
+# Update the BUILD files
+bazel configure || true
+# Run the application, starting a server
+bazel run cmd/hello &
+# Wait for the server
+while ! nc -z localhost 8080; do   
+  sleep 0.5
+done
+
+output=$(curl localhost:8080)
+# Verify the application output matches expectation
+[[ "${output}" =~ "Hello, world" ]] || {
+    echo >&2 "Wanted output containing 'Hello, world' but got '${output}'"
+    exit 1
+}
 
+# Shutdown server
+kill %1