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Commit 84bd5bf8 authored by Kousik Kumar's avatar Kousik Kumar
Browse files

Support fetching config files from experiments fetcher binary 

The expfetcher binary (added in
https://critique.corp.google.com/cl/424076941), can fetch experiments
configuration from CDPush and load them into Soong as part of its
startup. If the binary exists, then we use it to fetch experiments
config and put them in the out directory so that those env variables can
be loaded by Soong during startup and inturn control whether RBE should
be enabled or not.
Design doc: go/rbe-android-dev-gradual-rollout

Test:
1. time lunch aosp_bramble-userdebug (first lunch when "out" dir doesn't
   exist) - https://paste.googleplex.com/5824218777255936 - took ~9s and
   ran with RBE enabled.
2. time lunch aosp_bramble-userdebug (when "out" dir already exists) - https://paste.googleplex.com/6485045129773056 -
   took ~3.5s and ran with RBE enabled.
3. time lunch aosp_bramble-userdebug (when
   "vendor/google/tools/soong/expfetcher" doesn't exist) - https://paste.googleplex.com/6103083353374720 - took 6.5s
   and not RBE enabled.

Bug: b/215181607
Change-Id: Ie3c085498c59929119534aa98863566eecb8e4eb
parent 3ff037e3

ui/build/config.go

+69 −22
Original line number Diff line number Diff line
@@ -15,10 +15,12 @@ 
package build



import (

	"context"

	"encoding/json"

	"fmt"

	"io/ioutil"

	"os"

	"os/exec"

	"path/filepath"

	"runtime"

	"strconv"
@@ -35,6 +37,9 @@ import ( 
const (

	envConfigDir  = "vendor/google/tools/soong_config"

	jsonSuffix    = "json"



	configFetcher = "vendor/google/tools/soong/expconfigfetcher"

	envConfigFetchTimeout = 10 * time.Second

)



type Config struct{ *configImpl }
@@ -135,40 +140,82 @@ func checkTopDir(ctx Context) { 
	}

}



func loadEnvConfig(config *configImpl) error {

// fetchEnvConfig optionally fetches environment config from an

// experiments system to control Soong features dynamically.

func fetchEnvConfig(ctx Context, config *configImpl, envConfigName string) error {

	s, err := os.Stat(configFetcher)

	if err != nil {

		if os.IsNotExist(err) {

			return nil

		}

		return err

	}

	if s.Mode()&0111 == 0 {

		return fmt.Errorf("configuration fetcher binary %v is not executable: %v", configFetcher, s.Mode())

	}



	configExists := false

	outConfigFilePath := filepath.Join(config.OutDir(), envConfigName + jsonSuffix)

	if _, err := os.Stat(outConfigFilePath); err == nil {

		configExists = true

	}



	tCtx, cancel := context.WithTimeout(ctx, envConfigFetchTimeout)

	defer cancel()

	cmd := exec.CommandContext(tCtx, configFetcher, "-output_config_dir", config.OutDir())

	if err := cmd.Start(); err != nil {

		return err

	}



	// If a config file already exists, return immediately and run the config file

	// fetch in the background. Otherwise, wait for the config file to be fetched.

	if configExists {

		go cmd.Wait()

		return nil

	}

	if err := cmd.Wait(); err != nil {

		return err

	}

	return nil

}



func loadEnvConfig(ctx Context, config *configImpl) error {

	bc := os.Getenv("ANDROID_BUILD_ENVIRONMENT_CONFIG")

	if bc == "" {

		return nil

	}



	if err := fetchEnvConfig(ctx, config, bc); err != nil {

		fmt.Fprintf(os.Stderr, "Failed to fetch config file: %v", err)

	}



	configDirs := []string{

		os.Getenv("ANDROID_BUILD_ENVIRONMENT_CONFIG_DIR"),

		config.OutDir(),

		os.Getenv("ANDROID_BUILD_ENVIRONMENT_CONFIG_DIR"),

		envConfigDir,

	}

	var cfgFile string

	for _, dir := range configDirs {

		cfgFile = filepath.Join(os.Getenv("TOP"), dir, fmt.Sprintf("%s.%s", bc, jsonSuffix))

		if _, err := os.Stat(cfgFile); err == nil {

			break

		}

	}



		cfgFile := filepath.Join(os.Getenv("TOP"), dir, fmt.Sprintf("%s.%s", bc, jsonSuffix))

		envVarsJSON, err := ioutil.ReadFile(cfgFile)

		if err != nil {

		fmt.Fprintf(os.Stderr, "\033[33mWARNING:\033[0m failed to open config file %s: %s\n", cfgFile, err.Error())

		return nil

			continue

		}



		ctx.Verbosef("Loading config file %v\n", cfgFile)

		var envVars map[string]map[string]string

		if err := json.Unmarshal(envVarsJSON, &envVars); err != nil {

		return fmt.Errorf("env vars config file: %s did not parse correctly: %s", cfgFile, err.Error())

			fmt.Fprintf(os.Stderr, "Env vars config file %s did not parse correctly: %s", cfgFile, err.Error())

			continue

		}

		for k, v := range envVars["env"] {

			if os.Getenv(k) != "" {

				continue

			}

		config.Environment().Set(k, v)

			config.environ.Set(k, v)

		}

		ctx.Verbosef("Finished loading config file %v\n", cfgFile)

		break

	}



	return nil

}
@@ -203,7 +250,7 @@ func NewConfig(ctx Context, args ...string) Config { 


	// loadEnvConfig needs to know what the OUT_DIR is, so it should

	// be called after we determine the appropriate out directory.

	if err := loadEnvConfig(ret); err != nil {

	if err := loadEnvConfig(ctx, ret); err != nil {

		ctx.Fatalln("Failed to parse env config files: %v", err)

	}