Refactor config environment variable override code

pkg/config/config.go

@@ -71,45 +71,28 @@ func NewDefaultConfig() *Config {
 
 // SetConfigFromEnv updates the configuration managed by environment variables.
 func (c *Config) SetConfigFromEnv() error {
-	timeout := os.Getenv(contextTimeoutEnvVar)
-	if timeout != "" {
+	if timeout := os.Getenv(contextTimeoutEnvVar); timeout != "" {
 		i, err := strconv.Atoi(timeout)
 		if err != nil {
 			return err
 		}
 		c.CtxTimeOut = time.Duration(i) * time.Second
 	}
 
-	kanikoImage := os.Getenv(kanikoImageEnvVar)
-	if kanikoImage != "" {
+	if kanikoImage := os.Getenv(kanikoImageEnvVar); kanikoImage != "" {
 		c.KanikoContainerImage = kanikoImage
 	}
 
-	buildRunCompletionDurationBucketsEnvVarValue := os.Getenv(metricBuildRunCompletionDurationBucketsEnvVar)
-	if buildRunCompletionDurationBucketsEnvVarValue != "" {
-		buildRunCompletionDurationBuckets, err := stringToFloat64Array(strings.Split(buildRunCompletionDurationBucketsEnvVarValue, ","))
-		if err != nil {
-			return err
-		}
-		c.Prometheus.BuildRunCompletionDurationBuckets = buildRunCompletionDurationBuckets
+	if err := updateBucketsConfig(&c.Prometheus.BuildRunCompletionDurationBuckets, metricBuildRunCompletionDurationBucketsEnvVar); err != nil {
+		return err
 	}
 
-	buildRunEstablishDurationBucketsEnvVarValue := os.Getenv(metricBuildRunEstablishDurationBucketsEnvVar)
-	if buildRunEstablishDurationBucketsEnvVarValue != "" {
-		buildRunEstablishDurationBuckets, err := stringToFloat64Array(strings.Split(buildRunEstablishDurationBucketsEnvVarValue, ","))
-		if err != nil {
-			return err
-		}
-		c.Prometheus.BuildRunEstablishDurationBuckets = buildRunEstablishDurationBuckets
+	if err := updateBucketsConfig(&c.Prometheus.BuildRunEstablishDurationBuckets, metricBuildRunEstablishDurationBucketsEnvVar); err != nil {
+		return err
 	}
 
-	buildRunRampUpDurationBucketsEnvVarValue := os.Getenv(metricBuildRunRampUpDurationBucketsEnvVar)
-	if buildRunRampUpDurationBucketsEnvVarValue != "" {
-		buildRunRampUpDurationBuckets, err := stringToFloat64Array(strings.Split(buildRunRampUpDurationBucketsEnvVarValue, ","))
-		if err != nil {
-			return err
-		}
-		c.Prometheus.BuildRunRampUpDurationBuckets = buildRunRampUpDurationBuckets
+	if err := updateBucketsConfig(&c.Prometheus.BuildRunRampUpDurationBuckets, metricBuildRunRampUpDurationBucketsEnvVar); err != nil {
+		return err
 	}
 
 	c.Prometheus.HistogramEnabledLabels = strings.Split(os.Getenv(prometheusHistogramEnabledLabelsEnvVar), ",")
@@ -130,3 +113,16 @@ func stringToFloat64Array(strings []string) ([]float64, error) {
 
 	return floats, nil
 }
+
+func updateBucketsConfig(buckets *[]float64, envVarName string) error {
+	if values, found := os.LookupEnv(envVarName); found {
+		floats, err := stringToFloat64Array(strings.Split(values, ","))
+		if err != nil {
+			return err
+		}
+
+		*buckets = floats
+	}
+
+	return nil
+}

pkg/config/config_suite_test.go

@@ -0,0 +1,17 @@
+// Copyright The Shipwright Contributors
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package config_test
+
+import (
+	"testing"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+func TestConfig(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Config Suite")
+}

pkg/config/config_test.go

@@ -0,0 +1,91 @@
+// Copyright The Shipwright Contributors
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package config_test
+
+import (
+	"os"
+	"time"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	. "github.com/shipwright-io/build/pkg/config"
+)
+
+var _ = Describe("Config", func() {
+	Context("obtaining the configuration for build", func() {
+		It("should create a default configuration with reasonable values", func() {
+			config := NewDefaultConfig()
+			Expect(config).ToNot(BeNil())
+		})
+
+		It("should allow for an override of the context timeout using an environment variable", func() {
+			var overrides = map[string]string{"CTX_TIMEOUT": "600"}
+			configWithEnvVariableOverrides(overrides, func(config *Config) {
+				Expect(config.CtxTimeOut).To(Equal(600 * time.Second))
+			})
+		})
+
+		It("should allow for an override of the default Kaniko project image using an environment variable", func() {
+			var overrides = map[string]string{"KANIKO_CONTAINER_IMAGE": "gcr.io/kaniko-project/executor:v1.0.1"}
+			configWithEnvVariableOverrides(overrides, func(config *Config) {
+				Expect(config.KanikoContainerImage).To(Equal("gcr.io/kaniko-project/executor:v1.0.1"))
+			})
+		})
+
+		It("should allow for an override of the Prometheus buckets settings using an environment variable", func() {
+			var overrides = map[string]string{
+				"PROMETHEUS_BR_COMP_DUR_BUCKETS":   "1,2,3,4",
+				"PROMETHEUS_BR_EST_DUR_BUCKETS":    "10,20,30,40",
+				"PROMETHEUS_BR_RAMPUP_DUR_BUCKETS": "1,2,3,5,8,12,20",
+			}
+
+			configWithEnvVariableOverrides(overrides, func(config *Config) {
+				Expect(config.Prometheus.BuildRunCompletionDurationBuckets).To(Equal([]float64{1, 2, 3, 4}))
+				Expect(config.Prometheus.BuildRunEstablishDurationBuckets).To(Equal([]float64{10, 20, 30, 40}))
+				Expect(config.Prometheus.BuildRunRampUpDurationBuckets).To(Equal([]float64{1, 2, 3, 5, 8, 12, 20}))
+			})
+		})
+
+		It("should allow for an override of the Prometheus enabled labels using an environment variable", func() {
+			var overrides = map[string]string{"PROMETHEUS_HISTOGRAM_ENABLED_LABELS": "namespace,strategy"}
+			configWithEnvVariableOverrides(overrides, func(config *Config) {
+				Expect(config.Prometheus.HistogramEnabledLabels).To(Equal([]string{"namespace", "strategy"}))
+			})
+		})
+	})
+})
+
+func configWithEnvVariableOverrides(settings map[string]string, f func(config *Config)) {
+	var backup = make(map[string]*string, len(settings))
+	for k, v := range settings {
+		value, ok := os.LookupEnv(k)
+		switch ok {
+		case true:
+			backup[k] = &value
+
+		case false:
+			backup[k] = nil
+		}
+
+		os.Setenv(k, v)
+	}
+
+	config := NewDefaultConfig()
+	Expect(config).ToNot(BeNil())
+
+	err := config.SetConfigFromEnv()
+	Expect(err).ToNot(HaveOccurred())
+
+	f(config)
+
+	for k, v := range backup {
+		if v != nil {
+			os.Setenv(k, *v)
+		} else {
+			os.Unsetenv(k)
+		}
+	}
+}