registry: configurable client timeout (#24259)

* registry: configurable client timeout

* Update registry/client_test.go

    Fix env test cleanup

    Co-Authored-By: Alisdair McDiarmid <alisdair@users.noreply.github.com>

registry/client.go

@@ -26,7 +26,6 @@ import (
 const (
 	xTerraformGet      = "X-Terraform-Get"
 	xTerraformVersion  = "X-Terraform-Version"
-	requestTimeout     = 10 * time.Second
 	modulesServiceID   = "modules.v1"
 	providersServiceID = "providers.v1"
 
@@ -35,14 +34,27 @@ const (
 	// discovery requests with the remote registry.
 	registryDiscoveryRetryEnvName = "TF_REGISTRY_DISCOVERY_RETRY"
 	defaultRetry                  = 1
+
+	// registryClientTimeoutEnvName is the name of the environment variable that
+	// can be configured to customize the timeout duration (seconds) for module
+	// and provider discovery with the remote registry.
+	registryClientTimeoutEnvName = "TF_REGISTRY_CLIENT_TIMEOUT"
+
+	// defaultRequestTimeout is the default timeout duration for requests to the
+	// remote registry.
+	defaultRequestTimeout = 10 * time.Second
 )
 
-var discoveryRetry int
+var (
+	tfVersion = version.String()
 
-var tfVersion = version.String()
+	discoveryRetry int
+	requestTimeout time.Duration
+)
 
 func init() {
 	configureDiscoveryRetry()
+	configureRequestTimeout()
 }
 
 // Client provides methods to query Terraform Registries.
@@ -411,3 +423,16 @@ func maxRetryErrorHandler(resp *http.Response, err error, numTries int) (*http.R
 	}
 	return resp, fmt.Errorf("the request failed, please try again later: %d%s", resp.StatusCode, errMsg)
 }
+
+// configureRequestTimeout configures the registry client request timeout from
+// environment variables
+func configureRequestTimeout() {
+	requestTimeout = defaultRequestTimeout
+
+	if v := os.Getenv(registryClientTimeoutEnvName); v != "" {
+		timeout, err := strconv.Atoi(v)
+		if err == nil && timeout > 0 {
+			requestTimeout = time.Duration(timeout) * time.Second
+		}
+	}
+}

registry/client_test.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"strings"
 	"testing"
+	"time"
 
 	version "github.com/hashicorp/go-version"
 	"github.com/hashicorp/terraform-svchost/disco"
@@ -51,6 +52,42 @@ func TestConfigureDiscoveryRetry(t *testing.T) {
 	})
 }
 
+func TestConfigureRegistryClientTimeout(t *testing.T) {
+	t.Run("default timeout", func(t *testing.T) {
+		if requestTimeout != defaultRequestTimeout {
+			t.Fatalf("expected timeout %q, got %q",
+				defaultRequestTimeout.String(), requestTimeout.String())
+		}
+
+		rc := NewClient(nil, nil)
+		if rc.client.HTTPClient.Timeout != defaultRequestTimeout {
+			t.Fatalf("expected client timeout %q, got %q",
+				defaultRequestTimeout.String(), rc.client.HTTPClient.Timeout.String())
+		}
+	})
+
+	t.Run("configured timeout", func(t *testing.T) {
+		defer func(timeoutEnv string) {
+			os.Setenv(registryClientTimeoutEnvName, timeoutEnv)
+			requestTimeout = defaultRequestTimeout
+		}(os.Getenv(registryClientTimeoutEnvName))
+		os.Setenv(registryClientTimeoutEnvName, "20")
+
+		configureRequestTimeout()
+		expected := 20 * time.Second
+		if requestTimeout != expected {
+			t.Fatalf("expected timeout %q, got %q",
+				expected, requestTimeout.String())
+		}
+
+		rc := NewClient(nil, nil)
+		if rc.client.HTTPClient.Timeout != expected {
+			t.Fatalf("expected client timeout %q, got %q",
+				expected, rc.client.HTTPClient.Timeout.String())
+		}
+	})
+}
+
 func TestLookupModuleVersions(t *testing.T) {
 	server := test.Registry()
 	defer server.Close()

website/docs/commands/environment-variables.html.md

@@ -120,6 +120,14 @@ Set `TF_REGISTRY_DISCOVERY_RETRY` to configure the max number of request retries
 the remote registry client will attempt for client connection errors or
 500-range responses that are safe to retry.
 
+## TF_REGISTRY_CLIENT_TIMEOUT
+
+The default client timeout for requests to the remote registry is 10s. `TF_REGISTRY_CLIENT_TIMEOUT` can be configured and increased during extraneous circumstances.
+
+```shell
+export TF_REGISTRY_CLIENT_TIMEOUT=15
+```
+
 ## TF_CLI_CONFIG_FILE
 
 The location of the [Terraform CLI configuration file](/docs/commands/cli-config.html).