Support OTEL_EXPORTER_OTLP_LOGS_INSECURE and OTEL_EXPORTER_OTLP_INSECURE environments in grpc exporter (#5739)

Closes https://github.com/open-telemetry/opentelemetry-go/issues/5719

In this commit I add OTEL_EXPORTER_OTLP_LOGS_INSECURE and
OTEL_EXPORTER_OTLP_INSECURE env options to `otlploggrpc.Exporter`.

Now insecure option is fetched from env endpoint value
(OTEL_EXPORTER_OTLP_LOGS_ENDPOINT/OTEL_EXPORTER_OTLP_ENDPOINT).
According to
[spec](https://opentelemetry.io/docs/specs/otel/protocol/exporter/):
> Insecure: Whether to enable client transport security for the
exporter’s gRPC connection. This option only applies to OTLP/gRPC when
an endpoint is provided without the http or https scheme - OTLP/HTTP
always uses the scheme provided for the endpoint.

So with current behavior we have several problems:
- If default endpoint is used, we can't use insecure connection (with
setting OTEL_EXPORTER_OTLP_INSECURE).
- If endpoint provided with option without scheme (e.g. `WithEndpoint`)
we can't use insecure connection with env settings.
- If endpoint provided with env variable without scheme (e.g.
`//env.endpoint:8080/`) we can't use insecure connection.

This commit fixes this.

The same problem with `otlploghttp.Exporter`, and probably it should be
fixed there too.
I'm open to suggestions on how to fix the current behavior in a more
elegant way.

---------

Co-authored-by: Sam Xie <sam@samxie.me>
Co-authored-by: Damien Mathieu <42@dmathieu.com>

CHANGELOG.md

@@ -8,6 +8,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+### Added
+
+- Support `OTEL_EXPORTER_OTLP_LOGS_INSECURE` and `OTEL_EXPORTER_OTLP_INSECURE` environments in `go.opentelemetry.io/otel/exporters/otlp/otlplog/otlploggrpc`. (#5739)
+
 ### Fixed
 
 - Fix memory leak in the global `MeterProvider` when identical instruments are repeatedly created. (#5754)

exporters/otlp/otlplog/otlploggrpc/config.go

@@ -35,7 +35,10 @@ var (
 		"OTEL_EXPORTER_OTLP_LOGS_ENDPOINT",
 		"OTEL_EXPORTER_OTLP_ENDPOINT",
 	}
-	envInsecure = envEndpoint
+	envInsecure = []string{
+		"OTEL_EXPORTER_OTLP_LOGS_INSECURE",
+		"OTEL_EXPORTER_OTLP_INSECURE",
+	}
 
 	envHeaders = []string{
 		"OTEL_EXPORTER_OTLP_LOGS_HEADERS",
@@ -109,6 +112,7 @@ func newConfig(options []Option) config {
 		fallback[string](defaultEndpoint),
 	)
 	c.insecure = c.insecure.Resolve(
+		loadInsecureFromEnvEndpoint(envEndpoint),
 		getEnv[bool](envInsecure, convInsecure),
 	)
 	c.tlsCfg = c.tlsCfg.Resolve(
@@ -204,11 +208,7 @@ func WithEndpointURL(rawURL string) Option {
 	}
 	return fnOpt(func(c config) config {
 		c.endpoint = newSetting(u.Host)
-		if u.Scheme != "https" {
-			c.insecure = newSetting(true)
-		} else {
-			c.insecure = newSetting(false)
-		}
+		c.insecure = insecureFromScheme(c.insecure, u.Scheme)
 		return c
 	})
 }
@@ -394,15 +394,39 @@ func convEndpoint(s string) (string, error) {
 	return u.Host, nil
 }
 
-// convInsecure parses s as a URL string and returns if the connection should
-// use client transport security or not. If s is an invalid URL, false and an
-// error are returned.
+// convInsecure converts s from string to bool without case sensitivity.
+// If s is not valid returns error.
 func convInsecure(s string) (bool, error) {
-	u, err := url.Parse(s)
-	if err != nil {
-		return false, err
+	s = strings.ToLower(s)
+	if s != "true" && s != "false" {
+		return false, fmt.Errorf("can't convert %q to bool", s)
+	}
+
+	return s == "true", nil
+}
+
+// loadInsecureFromEnvEndpoint returns a resolver that fetches
+// insecure setting from envEndpoint is it possible.
+func loadInsecureFromEnvEndpoint(envEndpoint []string) resolver[bool] {
+	return func(s setting[bool]) setting[bool] {
+		if s.Set {
+			// Passed, valid, options have precedence.
+			return s
+		}
+
+		for _, key := range envEndpoint {
+			if vStr := os.Getenv(key); vStr != "" {
+				u, err := url.Parse(vStr)
+				if err != nil {
+					otel.Handle(fmt.Errorf("invalid %s value %s: %w", key, vStr, err))
+					continue
+				}
+
+				return insecureFromScheme(s, u.Scheme)
+			}
+		}
+		return s
 	}
-	return u.Scheme != "https", nil
 }
 
 // convHeaders converts the OTel environment variable header value s into a
@@ -529,6 +553,19 @@ func loadCertificates(certPath, keyPath string) ([]tls.Certificate, error) {
 	return []tls.Certificate{crt}, nil
 }
 
+// insecureFromScheme return setting if the connection should
+// use client transport security or not.
+// Empty scheme doesn't force insecure setting.
+func insecureFromScheme(prev setting[bool], scheme string) setting[bool] {
+	if scheme == "https" {
+		return newSetting(false)
+	} else if len(scheme) > 0 {
+		return newSetting(true)
+	}
+
+	return prev
+}
+
 func compressorToCompression(compressor string) Compression {
 	c, err := convCompression(compressor)
 	if err != nil {

exporters/otlp/otlplog/otlploggrpc/config_test.go

@@ -333,6 +333,83 @@ func TestNewConfig(t *testing.T) {
 				`invalid OTEL_EXPORTER_OTLP_LOGS_TIMEOUT value 100 seconds: strconv.Atoi: parsing "100 seconds": invalid syntax`,
 			},
 		},
+		{
+			name: "OptionEndpointURLWithoutScheme",
+			options: []Option{
+				WithEndpointURL("//env.endpoint:8080/prefix"),
+			},
+			want: config{
+				endpoint: newSetting("env.endpoint:8080"),
+				retryCfg: newSetting(defaultRetryCfg),
+				timeout:  newSetting(defaultTimeout),
+			},
+		},
+		{
+			name: "EnvEndpointWithoutScheme",
+			envars: map[string]string{
+				"OTEL_EXPORTER_OTLP_LOGS_ENDPOINT": "//env.endpoint:8080/prefix",
+			},
+			want: config{
+				endpoint: newSetting("env.endpoint:8080"),
+				retryCfg: newSetting(defaultRetryCfg),
+				timeout:  newSetting(defaultTimeout),
+			},
+		},
+		{
+			name: "DefaultEndpointWithEnvInsecure",
+			envars: map[string]string{
+				"OTEL_EXPORTER_OTLP_LOGS_INSECURE": "true",
+			},
+			want: config{
+				endpoint: newSetting(defaultEndpoint),
+				insecure: newSetting(true),
+				retryCfg: newSetting(defaultRetryCfg),
+				timeout:  newSetting(defaultTimeout),
+			},
+		},
+		{
+			name: "EnvEndpointWithoutSchemeWithEnvInsecure",
+			envars: map[string]string{
+				"OTEL_EXPORTER_OTLP_LOGS_ENDPOINT": "//env.endpoint:8080/prefix",
+				"OTEL_EXPORTER_OTLP_LOGS_INSECURE": "true",
+			},
+			want: config{
+				endpoint: newSetting("env.endpoint:8080"),
+				insecure: newSetting(true),
+				retryCfg: newSetting(defaultRetryCfg),
+				timeout:  newSetting(defaultTimeout),
+			},
+		},
+		{
+			name: "OptionEndpointURLWithoutSchemeWithEnvInsecure",
+			options: []Option{
+				WithEndpointURL("//env.endpoint:8080/prefix"),
+			},
+			envars: map[string]string{
+				"OTEL_EXPORTER_OTLP_LOGS_INSECURE": "true",
+			},
+			want: config{
+				endpoint: newSetting("env.endpoint:8080"),
+				insecure: newSetting(true),
+				retryCfg: newSetting(defaultRetryCfg),
+				timeout:  newSetting(defaultTimeout),
+			},
+		},
+		{
+			name: "OptionEndpointWithEnvInsecure",
+			options: []Option{
+				WithEndpoint("env.endpoint:8080"),
+			},
+			envars: map[string]string{
+				"OTEL_EXPORTER_OTLP_LOGS_INSECURE": "true",
+			},
+			want: config{
+				endpoint: newSetting("env.endpoint:8080"),
+				insecure: newSetting(true),
+				retryCfg: newSetting(defaultRetryCfg),
+				timeout:  newSetting(defaultTimeout),
+			},
+		},
 	}
 
 	for _, tc := range testcases {

exporters/otlp/otlplog/otlploggrpc/doc.go

@@ -18,6 +18,12 @@ The value should not contain a query string or fragment.
 OTEL_EXPORTER_OTLP_LOGS_ENDPOINT takes precedence over OTEL_EXPORTER_OTLP_ENDPOINT.
 The configuration can be overridden by [WithEndpoint], [WithEndpointURL], [WithInsecure], and [WithGRPCConn] options.
 
+OTEL_EXPORTER_OTLP_INSECURE, OTEL_EXPORTER_OTLP_LOGS_INSECURE (default: "false") -
+setting "true" disables client transport security for the exporter's gRPC connection.
+You can use this only when an endpoint is provided without scheme.
+OTEL_EXPORTER_OTLP_LOGS_INSECURE takes precedence over OTEL_EXPORTER_OTLP_INSECURE.
+The configuration can be overridden by [WithInsecure], [WithGRPCConn] options.
+
 OTEL_EXPORTER_OTLP_HEADERS, OTEL_EXPORTER_OTLP_LOGS_HEADERS (default: none) -
 key-value pairs used as gRPC metadata associated with gRPC requests.
 The value is expected to be represented in a format matching the [W3C Baggage HTTP Header Content Format],