cp env util from kubernetes/kubernetes

env/doc.go

@@ -0,0 +1,18 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+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 env provides utility functions for using environment variables.
+package env // import "k8s.io/utils/env"

env/env.go

@@ -0,0 +1,74 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+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 env
+
+import (
+	"os"
+	"strconv"
+)
+
+// GetString returns the env variable for the given key
+// and falls back to the given defaultValue if not set
+func GetString(key, defaultValue string) string {
+	v, ok := os.LookupEnv(key)
+	if ok {
+		return v
+	}
+	return defaultValue
+}
+
+// GetInt returns the env variable (parsed as integer) for
+// the given key and falls back to the given defaultValue if not set
+func GetInt(key string, defaultValue int) (int, error) {
+	v, ok := os.LookupEnv(key)
+	if ok {
+		value, err := strconv.Atoi(v)
+		if err != nil {
+			return defaultValue, err
+		}
+		return value, nil
+	}
+	return defaultValue, nil
+}
+
+// GetFloat64 returns the env variable (parsed as float64) for
+// the given key and falls back to the given defaultValue if not set
+func GetFloat64(key string, defaultValue float64) (float64, error) {
+	v, ok := os.LookupEnv(key)
+	if ok {
+		value, err := strconv.ParseFloat(v, 64)
+		if err != nil {
+			return defaultValue, err
+		}
+		return value, nil
+	}
+	return defaultValue, nil
+}
+
+// GetBool returns the env variable (parsed as bool) for
+// the given key and falls back to the given defaultValue if not set
+func GetBool(key string, defaultValue bool) (bool, error) {
+	v, ok := os.LookupEnv(key)
+	if ok {
+		value, err := strconv.ParseBool(v)
+		if err != nil {
+			return defaultValue, err
+		}
+		return value, nil
+	}
+	return defaultValue, nil
+}

env/env_test.go

@@ -0,0 +1,106 @@
+/*
+Copyright 2015 The Kubernetes Authors.
+
+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 env
+
+import (
+	"os"
+	"strconv"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetString(t *testing.T) {
+	const expected = "foo"
+
+	assert := assert.New(t)
+
+	key := "STRING_SET_VAR"
+	os.Setenv(key, expected)
+	assert.Equal(expected, GetString(key, "~"+expected))
+
+	key = "STRING_UNSET_VAR"
+	assert.Equal(expected, GetString(key, expected))
+}
+
+func TestGetInt(t *testing.T) {
+	const expected = 1
+	const defaultValue = 2
+
+	assert := assert.New(t)
+
+	key := "INT_SET_VAR"
+	os.Setenv(key, strconv.Itoa(expected))
+	returnVal, _ := GetInt(key, defaultValue)
+	assert.Equal(expected, returnVal)
+
+	key = "INT_UNSET_VAR"
+	returnVal, _ = GetInt(key, defaultValue)
+	assert.Equal(defaultValue, returnVal)
+
+	key = "INT_SET_VAR"
+	os.Setenv(key, "not-an-int")
+	returnVal, err := GetInt(key, defaultValue)
+	assert.Equal(defaultValue, returnVal)
+	if err == nil {
+		t.Error("expected error")
+	}
+}
+
+func TestGetFloat64(t *testing.T) {
+	const expected = 1.0
+	const defaultValue = 2.0
+
+	assert := assert.New(t)
+
+	key := "FLOAT_SET_VAR"
+	os.Setenv(key, "1.0")
+	returnVal, _ := GetFloat64(key, defaultValue)
+	assert.Equal(expected, returnVal)
+
+	key = "FLOAT_UNSET_VAR"
+	returnVal, _ = GetFloat64(key, defaultValue)
+	assert.Equal(defaultValue, returnVal)
+
+	key = "FLOAT_SET_VAR"
+	os.Setenv(key, "not-a-float")
+	returnVal, err := GetFloat64(key, defaultValue)
+	assert.Equal(defaultValue, returnVal)
+	assert.EqualError(err, "strconv.ParseFloat: parsing \"not-a-float\": invalid syntax")
+}
+
+func TestGetBool(t *testing.T) {
+	const expected = true
+	const defaultValue = false
+
+	assert := assert.New(t)
+
+	key := "BOOL_SET_VAR"
+	os.Setenv(key, "true")
+	returnVal, _ := GetBool(key, defaultValue)
+	assert.Equal(expected, returnVal)
+
+	key = "BOOL_UNSET_VAR"
+	returnVal, _ = GetBool(key, defaultValue)
+	assert.Equal(defaultValue, returnVal)
+
+	key = "BOOL_SET_VAR"
+	os.Setenv(key, "not-a-bool")
+	returnVal, err := GetBool(key, defaultValue)
+	assert.Equal(defaultValue, returnVal)
+	assert.EqualError(err, "strconv.ParseBool: parsing \"not-a-bool\": invalid syntax")
+}