a good start of making the ./_benchmarks benchmarker works autonomous by installing dependencies, running them and finally save them on disk as markdown files

Former-commit-id: 685b296f62c63f98455dce36ce52989be772ba34

_benchmarks/benchmarker/benchmarker.go

@@ -0,0 +1,148 @@
+package main
+
+import (
+	"bufio"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"runtime"
+
+	"github.com/kataras/golog"
+)
+
+var bundles = []bundle{
+	{
+		name:             "dotnet",
+		installDir:       "./dotnet_bin",
+		installArguments: []string{"-NoPath", "-InstallDir", "$installDir", "-Channel", "Current", "-Version", "3.0.100-preview6-012264"},
+	},
+}
+
+func install(b bundle) error {
+	switch b.name {
+	case "dotnet":
+		return installDotnet(b)
+	default:
+		return nil
+	}
+}
+
+type bundle struct {
+	name       string
+	installDir string
+
+	installArguments []string
+}
+
+func (b bundle) parseArguments() []string {
+	for i, arg := range b.installArguments {
+		if arg[0] == '$' {
+			// let's not use reflection here.
+			switch arg[1:] {
+			case "name":
+				b.installArguments[i] = b.name
+			case "installDir":
+				b.installArguments[i] = b.installDir
+			default:
+				panic(arg + " not a bundle struct field")
+			}
+		}
+	}
+
+	return b.installArguments
+}
+
+type platform struct {
+	executable string
+}
+
+func (p *platform) exec(args ...string) string {
+	cmd := exec.Command(p.executable, args...)
+	b, err := cmd.Output()
+	if err != nil {
+		golog.Error(err)
+		return ""
+	}
+
+	return string(b)
+}
+
+func (p *platform) attach(args ...string) error {
+	cmd := exec.Command(p.executable, args...)
+	attachCmd(cmd)
+	return cmd.Run()
+}
+
+func attachCmd(cmd *exec.Cmd) {
+	outputReader, err := cmd.StdoutPipe()
+	if err == nil {
+		outputScanner := bufio.NewScanner(outputReader)
+
+		go func() {
+			defer outputReader.Close()
+			for outputScanner.Scan() {
+				golog.Println(outputScanner.Text())
+			}
+		}()
+
+		errReader, err := cmd.StderrPipe()
+		if err == nil {
+			errScanner := bufio.NewScanner(errReader)
+			go func() {
+				defer errReader.Close()
+				for errScanner.Scan() {
+					golog.Println(errScanner.Text())
+				}
+			}()
+		}
+	}
+}
+
+func getPlatform(name string) (p *platform) {
+	for _, b := range bundles {
+		if b.name != name {
+			continue
+		}
+
+		// temporarily set the path env to the installation directories
+		// in order the exec.LookPath to check for programs there too.
+		pathEnv := os.Getenv("PATH")
+		if len(pathEnv) > 1 {
+			if pathEnv[len(pathEnv)-1] != ';' {
+				pathEnv += ";"
+			}
+		}
+
+		pathEnv += b.installDir
+		os.Setenv("PATH", pathEnv)
+		executable, err := exec.LookPath(name)
+		if err != nil {
+			golog.Debugf("%s executable couldn't be found from PATH. Trying to install it...", name)
+
+			err = install(b)
+			if err != nil {
+				golog.Fatalf("unable to auto-install %s, please do it yourself: %v", name, err)
+			}
+
+			executable = filepath.Join(b.installDir, name)
+			if runtime.GOOS == "windows" {
+				executable += ".exe"
+			}
+		}
+
+		return &platform{
+			executable: executable,
+		}
+	}
+
+	golog.Fatalf("%s not found", name)
+	return nil
+}
+
+func main() {
+	golog.SetLevel("debug")
+
+	dotnet := getPlatform("dotnet")
+	dotnetVersion := dotnet.exec("--version")
+	golog.Infof("Dotnet version: %s", dotnetVersion)
+}