added hooks and spec file for dynatrace

src/nodejs/hooks/dynatrace.go

@@ -0,0 +1,242 @@
+package hooks
+
+import (
+	"encoding/json"
+	"errors"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/cloudfoundry/libbuildpack"
+)
+
+type Command interface {
+	Execute(string, io.Writer, io.Writer, string, ...string) error
+}
+
+type DynatraceHook struct {
+	libbuildpack.DefaultHook
+	Log     *libbuildpack.Logger
+	Command Command
+}
+
+func init() {
+	logger := libbuildpack.NewLogger(os.Stdout)
+	command := &libbuildpack.Command{}
+
+	libbuildpack.AddHook(DynatraceHook{
+		Log:     logger,
+		Command: command,
+	})
+}
+
+func (h DynatraceHook) AfterCompile(stager *libbuildpack.Stager) error {
+	h.Log.Debug("Checking for enabled dynatrace service...")
+
+	credentials := h.dtCredentials()
+	if credentials == nil {
+		h.Log.Debug("Dynatrace service credentials not found!")
+		return nil
+	}
+
+	h.Log.Info("Dynatrace service credentials found. Setting up Dynatrace PaaS agent.")
+
+	skipErrors := credentials["skiperrors"]
+
+	apiurl, present := credentials["apiurl"]
+	if !present {
+		apiurl = "https://" + credentials["environmentid"] + ".live.dynatrace.com/api"
+	}
+
+	url := apiurl + "/v1/deployment/installer/agent/unix/paas-sh/latest?include=nodejs&include=process&bitness=64&Api-Token=" + credentials["apitoken"]
+	installerPath := filepath.Join(os.TempDir(), "paasInstaller.sh")
+
+	h.Log.Debug("Downloading '%s' to '%s'", url, installerPath)
+	err := h.downloadFile(url, installerPath)
+	if err != nil {
+		if skipErrors == "true" {
+			h.Log.Warning("Error during installer download, skipping installation")
+			return nil
+		}
+		return err
+	}
+
+	h.Log.Debug("Making %s executable...", installerPath)
+	os.Chmod(installerPath, 0755)
+
+	h.Log.BeginStep("Starting Dynatrace PaaS agent installer")
+
+	if os.Getenv("BP_DEBUG") != "" {
+		err = h.Command.Execute("", os.Stdout, os.Stderr, installerPath, stager.BuildDir())
+	} else {
+		err = h.Command.Execute("", ioutil.Discard, ioutil.Discard, installerPath, stager.BuildDir())
+	}
+	if err != nil {
+		return err
+	}
+
+	h.Log.Info("Dynatrace PaaS agent installed.")
+
+	dynatraceEnvName := "dynatrace-env.sh"
+	installDir := "dynatrace/oneagent"
+	dynatraceEnvPath := filepath.Join(stager.DepDir(), "profile.d", dynatraceEnvName)
+	agentLibPath, err := h.agentPath(filepath.Join(stager.BuildDir(), installDir))
+	if err != nil {
+		h.Log.Error("Manifest handling failed!")
+		return err
+	}
+
+	agentLibPath = filepath.Join(installDir, agentLibPath)
+
+	_, err = os.Stat(filepath.Join(stager.BuildDir(), agentLibPath))
+	if os.IsNotExist(err) {
+		h.Log.Error("Agent library (%s) not found!", filepath.Join(installDir, agentLibPath))
+		return err
+	}
+
+	h.Log.BeginStep("Setting up Dynatrace PaaS agent injection...")
+	h.Log.Debug("Copy %s to %s", dynatraceEnvName, dynatraceEnvPath)
+	err = libbuildpack.CopyFile(filepath.Join(stager.BuildDir(), installDir, dynatraceEnvName), dynatraceEnvPath)
+	if err != nil {
+		return err
+	}
+
+	h.Log.Debug("Open %s for modification...", dynatraceEnvPath)
+	f, err := os.OpenFile(dynatraceEnvPath, os.O_APPEND|os.O_WRONLY, os.ModeAppend)
+	if err != nil {
+		return err
+	}
+
+	defer f.Close()
+
+	h.Log.Debug("Write LD_PRELOAD...")
+	_, err = f.WriteString("\nexport LD_PRELOAD=${HOME}/" + agentLibPath)
+	if err != nil {
+		return err
+	}
+
+	h.Log.Debug("Write DT_HOST_ID...")
+	_, err = f.WriteString("\nexport DT_HOST_ID=" + h.appName() + "_${CF_INSTANCE_INDEX}")
+	if err != nil {
+		return err
+	}
+
+	h.Log.Info("Dynatrace PaaS agent injection is set up.")
+
+	return nil
+}
+
+func (h DynatraceHook) dtCredentials() map[string]string {
+	type Service struct {
+		Name        string            `json:"name"`
+		Credentials map[string]string `json:"credentials"`
+	}
+	var vcapServices map[string][]Service
+
+	err := json.Unmarshal([]byte(os.Getenv("VCAP_SERVICES")), &vcapServices)
+	if err != nil {
+		return nil
+	}
+
+	var detectedServices []Service
+
+	for _, services := range vcapServices {
+		for _, service := range services {
+			if strings.Contains(service.Name, "dynatrace") &&
+					service.Credentials["environmentid"] != "" &&
+					service.Credentials["apitoken"] != "" {
+				detectedServices = append(detectedServices, service)
+			}
+		}
+	}
+
+	if len(detectedServices) == 1 {
+		h.Log.Debug("Found one matching service: %s", detectedServices[0].Name)
+		return detectedServices[0].Credentials
+	} else if len(detectedServices) > 1 {
+		h.Log.Warning("More than one matching service found!")
+	}
+
+	return nil
+}
+
+func (h DynatraceHook) appName() string {
+	var application struct {
+		Name string `json:"name"`
+	}
+	err := json.Unmarshal([]byte(os.Getenv("VCAP_APPLICATION")), &application)
+	if err != nil {
+		return ""
+	}
+
+	return application.Name
+}
+
+func (h DynatraceHook) downloadFile(url, path string) error {
+	out, err := os.Create(path)
+	if err != nil {
+		return err
+	}
+
+	defer out.Close()
+
+	resp, err := http.Get(url)
+	if err != nil {
+		return err
+	}
+
+	if resp.StatusCode != 200 {
+		return errors.New("Download returned with status " + resp.Status)
+	}
+
+	defer resp.Body.Close()
+
+	_, err = io.Copy(out, resp.Body)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func (h DynatraceHook) agentPath(installDir string) (string, error) {
+	manifestPath := filepath.Join(installDir, "manifest.json")
+
+	type Binary struct {
+		Path string `json:"path"`
+		Md5 string `json:"md5"`
+		Version string `json:"version"`
+		Binarytype string `json:"binarytype,omitempty"`
+	}
+
+	type Architecture map[string][]Binary
+	type Technologies map[string]Architecture
+
+	type Manifest struct {
+		Tech Technologies`json:"technologies"`
+		Ver string `json:"version"`
+	}
+
+	var manifest Manifest
+
+	raw, err := ioutil.ReadFile(manifestPath)
+	if err != nil {
+		return "", err
+	}
+
+	err = json.Unmarshal(raw, &manifest) 
+	if err != nil {
+		return "", err
+	}
+
+	for _, binary := range manifest.Tech["process"]["linux-x86-64"] {
+		if binary.Binarytype ==	"primary" {
+			return binary.Path, nil
+		}
+	}
+
+	return "", errors.New("No primary binary for process agent found!")
+}