From a2e89054841d7176b41952bfabc0c21f48f413a6 Mon Sep 17 00:00:00 2001
From: Sam Xie <xsambundy@gmail.com>
Date: Sat, 6 Jun 2020 16:42:24 +0800
Subject: [PATCH] Use environment variables as default options

---
 exporters/trace/jaeger/env_test.go | 54 ++++++++++++++++++++++++++++--
 exporters/trace/jaeger/jaeger.go   |  1 +
 exporters/trace/jaeger/uploader.go |  7 ++++
 3 files changed, 60 insertions(+), 2 deletions(-)

diff --git a/exporters/trace/jaeger/env_test.go b/exporters/trace/jaeger/env_test.go
index ee383298c21e..5af9c1a23fa3 100644
--- a/exporters/trace/jaeger/env_test.go
+++ b/exporters/trace/jaeger/env_test.go
@@ -123,7 +123,7 @@ func TestNewRawExporterWithEnv(t *testing.T) {
 		username          = "user"
 		password          = "password"
 		serviceName       = "test-service"
-		disabled          = "disable"
+		disabled          = "false"
 		tags              = "key=value"
 	)
 
@@ -145,14 +145,64 @@ func TestNewRawExporterWithEnv(t *testing.T) {
 	// Create Jaeger Exporter with environment variables
 	exp, err := NewRawExporter(
 		WithCollectorEndpoint(CollectorEndpointFromEnv(), WithCollectorEndpointOptionFromEnv()),
+		WithDisabled(true),
 		WithDisabledFromEnv(),
 		WithProcessFromEnv(),
 	)
 
 	assert.NoError(t, err)
-	assert.Equal(t, exp.o.Disabled, false)
+	assert.Equal(t, false, exp.o.Disabled)
 	assert.EqualValues(t, serviceName, exp.process.ServiceName)
 	assert.Len(t, exp.process.Tags, 1)
+
+	require.IsType(t, &collectorUploader{}, exp.uploader)
+	uploader := exp.uploader.(*collectorUploader)
+	assert.Equal(t, collectorEndpoint, uploader.endpoint)
+	assert.Equal(t, username, uploader.username)
+	assert.Equal(t, password, uploader.password)
+}
+
+func TestNewRawExporterWithEnvImplicitly(t *testing.T) {
+	const (
+		collectorEndpoint = "http://localhost"
+		username          = "user"
+		password          = "password"
+		serviceName       = "test-service"
+		disabled          = "false"
+		tags              = "key=value"
+	)
+
+	require.NoError(t, os.Setenv(envEndpoint, collectorEndpoint))
+	require.NoError(t, os.Setenv(envUser, username))
+	require.NoError(t, os.Setenv(envPassword, password))
+	require.NoError(t, os.Setenv(envDisabled, disabled))
+	require.NoError(t, os.Setenv(envServiceName, serviceName))
+	require.NoError(t, os.Setenv(envTags, tags))
+	defer func() {
+		require.NoError(t, os.Unsetenv(envEndpoint))
+		require.NoError(t, os.Unsetenv(envUser))
+		require.NoError(t, os.Unsetenv(envPassword))
+		require.NoError(t, os.Unsetenv(envDisabled))
+		require.NoError(t, os.Unsetenv(envServiceName))
+		require.NoError(t, os.Unsetenv(envTags))
+	}()
+
+	// Create Jaeger Exporter with environment variables
+	exp, err := NewRawExporter(
+		WithCollectorEndpoint(""),
+		WithDisabled(true),
+	)
+
+	assert.NoError(t, err)
+	assert.Equal(t, false, exp.o.Disabled)
+	assert.EqualValues(t, serviceName, exp.process.ServiceName)
+	assert.Len(t, exp.process.Tags, 1)
+
+	require.IsType(t, &collectorUploader{}, exp.uploader)
+	uploader := exp.uploader.(*collectorUploader)
+	assert.Equal(t, collectorEndpoint, uploader.endpoint)
+	assert.Equal(t, username, uploader.username)
+	assert.Equal(t, password, uploader.password)
 }
 
 func TestCollectorEndpointFromEnv(t *testing.T) {
diff --git a/exporters/trace/jaeger/jaeger.go b/exporters/trace/jaeger/jaeger.go
index 7fe1ba43d33d..0932b3abc291 100644
--- a/exporters/trace/jaeger/jaeger.go
+++ b/exporters/trace/jaeger/jaeger.go
@@ -89,6 +89,7 @@ func WithDisabled(disabled bool) Option {
 // the collected spans to Jaeger.
 func NewRawExporter(endpointOption EndpointOption, opts ...Option) (*Exporter, error) {
 	o := options{}
+	opts = append(opts, WithDisabledFromEnv(), WithProcessFromEnv())
 	for _, opt := range opts {
 		opt(&o)
 	}
diff --git a/exporters/trace/jaeger/uploader.go b/exporters/trace/jaeger/uploader.go
index 158d02d477c9..3f3f848c55f5 100644
--- a/exporters/trace/jaeger/uploader.go
+++ b/exporters/trace/jaeger/uploader.go
@@ -55,6 +55,11 @@ func WithAgentEndpoint(agentEndpoint string) EndpointOption {
 // For example, http://localhost:14268/api/traces
 func WithCollectorEndpoint(collectorEndpoint string, options ...CollectorEndpointOption) EndpointOption {
 	return func() (batchUploader, error) {
+		// Overwrite collector endpoint if environment variables are available.
+		if e := CollectorEndpointFromEnv(); e != "" {
+			collectorEndpoint = e
+		}
+
 		if collectorEndpoint == "" {
 			return nil, errors.New("collectorEndpoint must not be empty")
 		}
@@ -62,6 +67,8 @@ func WithCollectorEndpoint(collectorEndpoint string, options ...CollectorEndpoin
 		o := &CollectorEndpointOptions{
 			httpClient: http.DefaultClient,
 		}
+
+		options = append(options, WithCollectorEndpointOptionFromEnv())
 		for _, opt := range options {
 			opt(o)
 		}