feat: Implemented Go SDK env var handling (#975)

Also added unit tests for it that will leave existing environment variables undisturbed. (Will store env vars before test and restore env vars after test)

Author: jeremytchang

go/rtl/constants.go

@@ -1,5 +1,10 @@
 package rtl
 
 const (
-	DefaultApiVersion = "4.0"
+	baseUrlEnvKey = "LOOKERSDK_BASE_URL"
+	apiVersionEnvKey = "LOOKERSDK_API_VERSION"
+	verifySslEnvKey = "LOOKERSDK_VERIFY_SSL"
+	timeoutEnvKey = "LOOKERSDK_TIMEOUT"
+	clientIdEnvKey = "LOOKERSDK_CLIENT_ID"
+	clientSecretEnvKey = "LOOKERSDK_CLIENT_SECRET"
 )

go/rtl/settings.go

@@ -3,6 +3,9 @@ package rtl
 import (
 	"fmt"
 	"gopkg.in/ini.v1"
+	"os"
+	"strconv"
+	"strings"
 )
 
 var defaultSectionName string = "Looker"
@@ -18,15 +21,19 @@ type ApiSettings struct {
 	ApiVersion   string `ini:"api_version"`
 }
 
+var defaultSettings ApiSettings = ApiSettings{
+	VerifySsl:  true,
+	ApiVersion: "4.0",
+	Timeout: 120,
+}
+
 func NewSettingsFromFile(file string, section *string) (ApiSettings, error) {
 	if section == nil {
 		section = &defaultSectionName
 	}
 
-	s := ApiSettings{
-		VerifySsl:  true,
-		ApiVersion: DefaultApiVersion,
-	}
+	// Default values
+	s := defaultSettings
 
 	cfg, err := ini.Load(file)
 	if err != nil {
@@ -37,3 +44,32 @@ func NewSettingsFromFile(file string, section *string) (ApiSettings, error) {
 	return s, err
 
 }
+
+func NewSettingsFromEnv() (ApiSettings, error) {
+	settings := defaultSettings
+
+	if v, present  := os.LookupEnv(baseUrlEnvKey); present {
+		settings.BaseUrl = v
+	}
+	if v, present  := os.LookupEnv(apiVersionEnvKey); present {
+		settings.ApiVersion = v
+	}
+	if v, present  := os.LookupEnv(verifySslEnvKey); present {
+		s := strings.ToLower(v)
+		settings.VerifySsl = s == "true" || s == "t" || s == "1" || s == "y" || s == "yes"
+	}
+	if v, present  := os.LookupEnv(timeoutEnvKey); present {
+		timeout, err := strconv.ParseInt(v,10,32)
+		if err == nil {
+			settings.Timeout = int32(timeout)
+		}
+	}
+	if v, present  := os.LookupEnv(clientIdEnvKey); present {
+		settings.ClientId = v
+	}
+	if v, present  := os.LookupEnv(clientSecretEnvKey); present {
+		settings.ClientSecret = v
+	}
+
+	return settings, nil
+}

go/rtl/settings_test.go

@@ -1,6 +1,7 @@
 package rtl
 
 import (
+	"os"
 	"reflect"
 	"testing"
 )
@@ -48,3 +49,106 @@ func TestNewSettingsFromFile(t *testing.T) {
 		})
 	}
 }
+
+type pair struct {
+	k string
+	v string
+}
+
+func TestNewSettingsFromEnv(t *testing.T) {
+	getEnv := func() []pair {
+		var pairs []pair
+
+		if v,present := os.LookupEnv(baseUrlEnvKey); present {
+			pairs = append(pairs, pair{ k: baseUrlEnvKey, v: v })
+		}
+		if v,present := os.LookupEnv(apiVersionEnvKey); present {
+			pairs = append(pairs, pair{ k: apiVersionEnvKey, v: v })
+		}
+		if v,present := os.LookupEnv(verifySslEnvKey); present {
+			pairs = append(pairs, pair{ k: verifySslEnvKey, v: v })
+		}
+		if v,present := os.LookupEnv(timeoutEnvKey); present {
+			pairs = append(pairs, pair{ k: timeoutEnvKey, v: v })
+		}
+		if v,present := os.LookupEnv(clientIdEnvKey); present {
+			pairs = append(pairs, pair{ k: clientIdEnvKey, v: v })
+		}
+		if v,present := os.LookupEnv(clientSecretEnvKey); present {
+			pairs = append(pairs, pair{ k: clientSecretEnvKey, v: v })
+		}
+
+		return pairs
+	}
+
+	clearEnv := func() {
+		os.Unsetenv(baseUrlEnvKey)
+		os.Unsetenv(apiVersionEnvKey)
+		os.Unsetenv(verifySslEnvKey)
+		os.Unsetenv(timeoutEnvKey)
+		os.Unsetenv(clientIdEnvKey)
+		os.Unsetenv(clientSecretEnvKey)
+	}
+
+	setEnv := func(pairs []pair ) {
+		clearEnv()
+		for _, pair  := range pairs {
+			os.Setenv(pair.k, pair.v)
+		}
+	}
+
+	tests := []struct {
+		name    string
+		env     []pair
+		want    ApiSettings
+	}{
+		{
+			name: "NewSettingsFromEnv() returns settings when all environment variables set",
+			env: []pair {
+				{baseUrlEnvKey, "url"},
+				{apiVersionEnvKey, "5.0"},
+				{verifySslEnvKey, "false"},
+				{timeoutEnvKey, "360"},
+				{clientIdEnvKey, "id"},
+				{clientSecretEnvKey, "secret"},
+			},
+			want: ApiSettings{
+				BaseUrl:      "url",
+				ApiVersion:   "5.0",
+				VerifySsl:    false,
+				Timeout:      360,
+				ClientId:     "id",
+				ClientSecret: "secret",
+			},
+		},
+		{
+			name: "NewSettingsFromEnv() sets defaults correctly if env vars not set for them",
+			env: []pair {
+				{baseUrlEnvKey, "url"},
+				{clientIdEnvKey, "id"},
+				{clientSecretEnvKey, "secret"},
+			},
+			want: ApiSettings{
+				BaseUrl:      "url",
+				ApiVersion:   "4.0",
+				VerifySsl:    true,
+				Timeout:      120,
+				ClientId:     "id",
+				ClientSecret: "secret",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			origEnv := getEnv()
+			defer setEnv(origEnv)
+
+			setEnv(tt.env)
+
+			got, _ := NewSettingsFromEnv()
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("NewSettingsFromEnv() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}