From b6732c76921cc4491f7eaad6da92f21b083b1627 Mon Sep 17 00:00:00 2001
From: Devang Gaur <devang.gaur@accurics.com>
Date: Tue, 16 Mar 2021 03:50:50 +0530
Subject: [PATCH] policy download refactor (#618)

---
 pkg/config/global.go          |  4 ++--
 pkg/initialize/run.go         | 44 ++++++++++++++++++-----------------
 pkg/policy/cloud-providers.go |  2 +-
 3 files changed, 26 insertions(+), 24 deletions(-)

diff --git a/pkg/config/global.go b/pkg/config/global.go
index 91bcc5c7e..20db033b8 100644
--- a/pkg/config/global.go
+++ b/pkg/config/global.go
@@ -32,8 +32,8 @@ const (
 )
 
 var (
-	policyRepoPath = filepath.Join(utils.GetHomeDir(), ".terrascan")
-	policyBasePath = filepath.Join(policyRepoPath, "pkg", "policies", "opa", "rego")
+	policyBasePath = filepath.Join(utils.GetHomeDir(), ".terrascan")
+	policyRepoPath = filepath.Join(policyBasePath, "pkg", "policies", "opa", "rego")
 )
 
 func init() {
diff --git a/pkg/initialize/run.go b/pkg/initialize/run.go
index cec6f36f9..c7813d0ba 100644
--- a/pkg/initialize/run.go
+++ b/pkg/initialize/run.go
@@ -18,7 +18,7 @@ package initialize
 
 import (
 	"fmt"
-	"io/ioutil"
+	"net/http"
 	"os"
 
 	"github.com/accurics/terrascan/pkg/config"
@@ -29,23 +29,30 @@ import (
 )
 
 var (
-	basePath       = config.GetPolicyRepoPath()
-	basePolicyPath = config.GetPolicyBasePath()
+	policyRepoPath = config.GetPolicyRepoPath()
+	policyBasePath = config.GetPolicyBasePath()
 	repoURL        = config.GetPolicyRepoURL()
 	branch         = config.GetPolicyBranch()
+	noConnectionErr = fmt.Errorf("could not connect to github.com")
 )
 
+const terrascanReadmeURL string = "https://raw.githubusercontent.com/accurics/terrascan/master/README.md"
+
 // Run initializes terrascan if not done already
 func Run(isScanCmd bool) error {
 	zap.S().Debug("initializing terrascan")
 
 	// check if policy paths exist
-	if path, err := os.Stat(basePolicyPath); err == nil && path.IsDir() {
+	if path, err := os.Stat(policyRepoPath); err == nil && path.IsDir() {
 		if isScanCmd {
 			return nil
 		}
 	}
 
+	if !connected(terrascanReadmeURL) {
+		return noConnectionErr
+	}
+
 	// download policies
 	if err := DownloadPolicies(); err != nil {
 		return err
@@ -59,17 +66,17 @@ func Run(isScanCmd bool) error {
 func DownloadPolicies() error {
 	zap.S().Debug("downloading policies")
 
-	tempPath, err := ioutil.TempDir("", "terrascan-")
-	if err != nil {
-		return fmt.Errorf("failed to create temporary directory. error: '%v'", err)
-	}
+	zap.S().Debugf("base directory path : %s", policyBasePath)
+	zap.S().Debugf("policy directory path : %s", policyRepoPath)
+	zap.S().Debugf("policy repo url : %s", repoURL)
+	zap.S().Debugf("policy repo git branch : %s", branch)
 
-	defer os.RemoveAll(tempPath)
+	os.RemoveAll(policyBasePath)
 
-	zap.S().Debugf("cloning terrascan repo at %s", tempPath)
+	zap.S().Debugf("cloning terrascan repo at %s", policyBasePath)
 
 	// clone the repo
-	r, err := git.PlainClone(tempPath, false, &git.CloneOptions{
+	r, err := git.PlainClone(policyBasePath, false, &git.CloneOptions{
 		URL: repoURL,
 	})
 	if err != nil {
@@ -99,15 +106,10 @@ func DownloadPolicies() error {
 		return fmt.Errorf("failed to checkout git branch '%v'. error: '%v'", branch, err)
 	}
 
-	// cleaning the existing cached policies at basePath
-	if err = os.RemoveAll(basePath); err != nil {
-		return fmt.Errorf("failed to clean up the directory '%s'. error: '%v'", basePath, err)
-	}
-
-	// move the freshly cloned repo from tempPath to basePath
-	if err = os.Rename(tempPath, basePath); err != nil {
-		return fmt.Errorf("failed to install policies to '%s'. error: '%v'", basePath, err)
-	}
-
 	return nil
 }
+
+func connected(url string) bool {
+	_, err := http.Get(url)
+	return err == nil
+}
diff --git a/pkg/policy/cloud-providers.go b/pkg/policy/cloud-providers.go
index 9bf75f140..447fae88e 100644
--- a/pkg/policy/cloud-providers.go
+++ b/pkg/policy/cloud-providers.go
@@ -50,7 +50,7 @@ var defaultIacType = make(map[supportedCloudType]supportedIacType)
 var defaultIacVersion = make(map[supportedCloudType]supportedIacVersion)
 
 var (
-	basePolicyPath = config.GetPolicyBasePath()
+	basePolicyPath = config.GetPolicyRepoPath()
 )
 
 func registerActualCloudProvider(cloudType supportedCloudType, iacTypeDefault supportedIacType, iacVersionDefault supportedIacVersion, isIndirect bool, getPolicyPaths func() []string) {