add support for env var configuration to otlp/gRPC (open-telemetry#1811)

* move options to `otlpconfig` internal package

* add support for env configs on otel/gRPC

* remove duplicate code

* refactor options

* format imports

* move marshal option to oltphttp

* clone tls configs and tests grpc certificates

* add more context to http errors

* add todo

* add entry to changelog

* update changelog with pr number

* apply suggestions

Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>

CHANGELOG.md

@@ -16,7 +16,7 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Adds test to check BatchSpanProcessor ignores `OnEnd` and `ForceFlush` post `Shutdown`. (#1772)
 - Option `ExportTimeout` was added to batch span processor. (#1755)
 - Adds semantic conventions for exceptions. (#1492)
-- Added support for configuring OTLP/HTTP Endpoints, Headers, Compression and Timeout via the Environment Variables. (#1758)
+- Added support for configuring OTLP/HTTP and OTLP/gRPC Endpoints, TLS Certificates, Headers, Compression and Timeout via Environment Variables. (#1758, #1769 and #1811)
   - `OTEL_EXPORTER_OTLP_ENDPOINT`
   - `OTEL_EXPORTER_OTLP_TRACES_ENDPOINT`
   - `OTEL_EXPORTER_OTLP_METRICS_ENDPOINT`
@@ -29,7 +29,6 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
   - `OTEL_EXPORTER_OTLP_TIMEOUT`
   - `OTEL_EXPORTER_OTLP_TRACES_TIMEOUT`
   - `OTEL_EXPORTER_OTLP_METRICS_TIMEOUT`
-- Added support for configuring OTLP/HTTP TLS Certificates via the Environment Variables. (#1769)
   - `OTEL_EXPORTER_OTLP_CERTIFICATE`
   - `OTEL_EXPORTER_OTLP_TRACES_CERTIFICATE`
   - `OTEL_EXPORTER_OTLP_METRICS_CERTIFICATE`

exporters/otlp/otlphttp/envconfig.go → exporters/otlp/internal/otlpconfig/envconfig.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package otlphttp
+package otlpconfig
 
 import (
 	"crypto/tls"
@@ -24,37 +24,50 @@ import (
 	"strings"
 	"time"
 
-	"go.opentelemetry.io/otel"
+	"go.opentelemetry.io/otel/exporters/otlp"
 
-	"go.opentelemetry.io/otel/exporters/otlp/internal/otlpconfig"
+	"go.opentelemetry.io/otel"
 )
 
-func applyEnvConfigs(cfg *config) {
-	e := envOptionsReader{
-		getEnv:   os.Getenv,
-		readFile: ioutil.ReadFile,
+func ApplyGRPCEnvConfigs(cfg *Config) {
+	e := EnvOptionsReader{
+		GetEnv:   os.Getenv,
+		ReadFile: ioutil.ReadFile,
 	}
 
-	opts := e.getOptionsFromEnv()
-	for _, opt := range opts {
-		opt.Apply(cfg)
+	e.ApplyGRPCEnvConfigs(cfg)
+}
+
+func ApplyHTTPEnvConfigs(cfg *Config) {
+	e := EnvOptionsReader{
+		GetEnv:   os.Getenv,
+		ReadFile: ioutil.ReadFile,
 	}
+
+	e.ApplyHTTPEnvConfigs(cfg)
+}
+
+type EnvOptionsReader struct {
+	GetEnv   func(string) string
+	ReadFile func(filename string) ([]byte, error)
 }
 
-type envOptionsReader struct {
-	getEnv   func(string) string
-	readFile func(filename string) ([]byte, error)
+func (e *EnvOptionsReader) ApplyHTTPEnvConfigs(cfg *Config) {
+	opts := e.GetOptionsFromEnv()
+	for _, opt := range opts {
+		opt.ApplyHTTPOption(cfg)
+	}
 }
 
-func (e *envOptionsReader) applyEnvConfigs(cfg *config) {
-	opts := e.getOptionsFromEnv()
+func (e *EnvOptionsReader) ApplyGRPCEnvConfigs(cfg *Config) {
+	opts := e.GetOptionsFromEnv()
 	for _, opt := range opts {
-		opt.Apply(cfg)
+		opt.ApplyGRPCOption(cfg)
 	}
 }
 
-func (e *envOptionsReader) getOptionsFromEnv() []Option {
-	var opts []Option
+func (e *EnvOptionsReader) GetOptionsFromEnv() []GenericOption {
+	var opts []GenericOption
 
 	// Endpoint
 	if v, ok := e.getEnvValue("ENDPOINT"); ok {
@@ -132,28 +145,28 @@ func (e *envOptionsReader) getOptionsFromEnv() []Option {
 	return opts
 }
 
-// getEnvValue gets an OTLP environment variable value of the specified key using the getEnv function.
+// getEnvValue gets an OTLP environment variable value of the specified key using the GetEnv function.
 // This function already prepends the OTLP prefix to all key lookup.
-func (e *envOptionsReader) getEnvValue(key string) (string, bool) {
-	v := strings.TrimSpace(e.getEnv(fmt.Sprintf("OTEL_EXPORTER_OTLP_%s", key)))
+func (e *EnvOptionsReader) getEnvValue(key string) (string, bool) {
+	v := strings.TrimSpace(e.GetEnv(fmt.Sprintf("OTEL_EXPORTER_OTLP_%s", key)))
 	return v, v != ""
 }
 
-func (e *envOptionsReader) readTLSConfig(path string) (*tls.Config, error) {
-	b, err := e.readFile(path)
+func (e *EnvOptionsReader) readTLSConfig(path string) (*tls.Config, error) {
+	b, err := e.ReadFile(path)
 	if err != nil {
 		return nil, err
 	}
-	return otlpconfig.CreateTLSConfig(b)
+	return CreateTLSConfig(b)
 }
 
-func stringToCompression(value string) Compression {
+func stringToCompression(value string) otlp.Compression {
 	switch value {
 	case "gzip":
-		return GzipCompression
+		return otlp.GzipCompression
 	}
 
-	return NoCompression
+	return otlp.NoCompression
 }
 
 func stringToHeader(value string) map[string]string {

exporters/otlp/otlphttp/envconfig_test.go → exporters/otlp/internal/otlpconfig/envconfig_test.go

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package otlphttp
+package otlpconfig
 
 import (
 	"reflect"