Allow configuration of global policy config, fix some typos

pkg/config/global.go

@@ -17,12 +17,17 @@
 package config
 
 import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"log" // we log from init(), so can't rely on zap to be available
 	"os"
 )
 
 const (
-	policyRepoURL = "https://github.com/accurics/terrascan.git"
-	policyBranch  = "master"
+	policyRepoURL    = "https://github.com/accurics/terrascan.git"
+	policyBranch     = "master"
+	configEnvvarName = "TERRASCAN_CONFIG"
 )
 
 var (
@@ -31,12 +36,55 @@ var (
 )
 
 func init() {
+	loadGlobalConfig()
+}
+
+func loadGlobalConfig() {
+	// Start with the defaults
 	Global.Policy = PolicyConfig{
 		BasePath: policyBasePath,
 		RepoPath: policyRepoPath,
 		RepoURL:  policyRepoURL,
 		Branch:   policyBranch,
 	}
+
+	// If the user specifies a config file in TERRASCAN_CONFIG,
+	// overwrite the defaults with the values from that file.
+	// Retain the defaults for members not specified in the file.
+	configFile := os.Getenv(configEnvvarName)
+
+	if len(configFile) > 0 {
+		p, err := loadConfigFile(configFile)
+		if err != nil {
+			log.Println(err)
+			return
+		}
+		if len(p.Policy.BasePath) > 0 {
+			Global.Policy.BasePath = p.Policy.BasePath
+		}
+		if len(p.Policy.RepoPath) > 0 {
+			Global.Policy.RepoPath = p.Policy.RepoPath
+		}
+		if len(p.Policy.RepoURL) > 0 {
+			Global.Policy.RepoURL = p.Policy.RepoURL
+		}
+		if len(p.Policy.Branch) > 0 {
+			Global.Policy.Branch = p.Policy.Branch
+		}
+	}
+}
+
+func loadConfigFile(configFile string) (GlobalConfig, error) {
+	p := GlobalConfig{}
+	data, err := ioutil.ReadFile(configFile)
+	if err != nil {
+		return p, fmt.Errorf("unable to read config file: %v", err)
+	}
+
+	if err = json.Unmarshal(data, &p); err != nil {
+		return p, fmt.Errorf("unable to unmarshal config file %s: %v", configFile, err)
+	}
+	return p, nil
 }
 
 // GetPolicyBasePath returns policy base path as set in global config

pkg/config/global_test.go

@@ -0,0 +1,57 @@
+/*
+    Copyright (C) 2020 Accurics, Inc.
+
+	Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+		http://www.apache.org/licenses/LICENSE-2.0
+
+	Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+package config
+
+import (
+	"os"
+	"testing"
+)
+
+func testConfigEnv(configPath string, t *testing.T) {
+	// Load the test data to compare against
+	config, err := loadConfigFile(configPath)
+	if err != nil {
+		t.Error(err)
+	}
+
+	// Set the environment variable and make sure the global config is set
+	oldenv := os.Getenv(configEnvvarName)
+	os.Setenv(configEnvvarName, configPath)
+	defer os.Setenv(configEnvvarName, oldenv)
+
+	loadGlobalConfig()
+
+	if Global.Policy.BasePath != config.Policy.BasePath {
+		t.Errorf("BasePath not overridden!  %v != %v", Global.Policy.BasePath, config.Policy.BasePath)
+	}
+
+	if Global.Policy.RepoPath != config.Policy.RepoPath {
+		t.Errorf("RepoPath not overridden!  %v != %v", Global.Policy.RepoPath, config.Policy.RepoPath)
+	}
+
+	if Global.Policy.RepoURL != config.Policy.RepoURL {
+		t.Errorf("RepoURL not overridden!  %v != %v", Global.Policy.RepoURL, config.Policy.RepoURL)
+	}
+
+	if Global.Policy.Branch != config.Policy.Branch {
+		t.Errorf("Branch not overridden!  %v != %v", Global.Policy.Branch, config.Policy.Branch)
+	}
+}
+
+func TestConfigFileLoadsCorrectly(t *testing.T) {
+	testConfigEnv("./testdata/terrascan-config.json", t)
+}

pkg/config/testdata/terrascan-config.json

@@ -0,0 +1,8 @@
+{
+   "policy": {
+        "path": "custom-path",
+        "rego_subdir": "rego-subdir",
+        "repo_url": "https://repository/url",
+        "branch": "branch-name"
+    }
+}

pkg/config/types.go

@@ -21,16 +21,16 @@ var Global *GlobalConfig = &GlobalConfig{}
 
 // GlobalConfig struct defines global variables/configurations across terrascan
 type GlobalConfig struct {
-	Policy PolicyConfig
+	Policy PolicyConfig `json:"policy"`
 }
 
 // PolicyConfig struct define policy specific configurations
 type PolicyConfig struct {
 	// policy local path
-	BasePath string
-	RepoPath string
+	BasePath string `json:"rego_subdir"`
+	RepoPath string `json:"path"`
 
 	// policy git url and branch
-	RepoURL string
-	Branch  string
+	RepoURL string `json:"repo_url"`
+	Branch  string `json:"branch"`
 }

pkg/writer/writer.go

@@ -32,7 +32,7 @@ func Write(format string, data interface{}, writer io.Writer) error {
 
 	writerFunc, present := writerMap[supportedFormat(format)]
 	if !present {
-		zap.S().Error("output format '%s' not supported", format)
+		zap.S().Errorf("output format '%s' not supported", format)
 		return errNotSupported
 	}
 

scripts/validate-gofmt.sh

@@ -16,6 +16,7 @@ bad_files=$(find_files | xargs gofmt -d -s 2>&1)
 if [[ -n "${bad_files}" ]]; then
   echo "${bad_files}" >&2
   echo >&2
-  echo "fix gofmt errors by running:\n./hack/fix-gofmt.sh" >&2
+  echo "fix gofmt errors by running:" >&2
+  echo "./scripts/fix-gofmt.sh" >&2
   exit 1
 fi