Add request_reason provider support

mmv1/third_party/terraform/utils/config.go.erb

@@ -92,6 +92,7 @@ type Config struct {
 	Scopes                              []string
 	BatchingConfig                      *batchingConfig
 	UserProjectOverride                 bool
+	RequestReason                       string
 	RequestTimeout                      time.Duration
 	// PollInterval is passed to resource.StateChangeConf in common_operation.go
 	// It controls the interval at which we poll for successful operations
@@ -226,7 +227,7 @@ func (c *Config) LoadAndValidate(ctx context.Context) error {
 
 	// 4. Header Transport - outer wrapper to inject additional headers we want to apply
 	// before making requests
-	headerTransport := newTransportWithHeaders(retryTransport)
+	headerTransport := newTransportWithHeaders(retryTransport, c.RequestReason)
 
 	// Set final transport value.
 	client.Transport = headerTransport

mmv1/third_party/terraform/utils/header_transport.go

@@ -2,7 +2,6 @@ package google
 
 import (
 	"net/http"
-	"os"
 )
 
 // adapted from https://stackoverflow.com/questions/51325704/adding-a-default-http-header-in-go
@@ -11,14 +10,14 @@ type headerTransportLayer struct {
 	baseTransit http.RoundTripper
 }
 
-func newTransportWithHeaders(baseTransit http.RoundTripper) headerTransportLayer {
+func newTransportWithHeaders(baseTransit http.RoundTripper, configRequestReason string) headerTransportLayer {
 	if baseTransit == nil {
 		baseTransit = http.DefaultTransport
 	}
 
 	headers := make(http.Header)
-	if requestReason := os.Getenv("CLOUDSDK_CORE_REQUEST_REASON"); requestReason != "" {
-		headers.Set("X-Goog-Request-Reason", requestReason)
+	if configRequestReason != "" {
+		headers.Set("X-Goog-Request-Reason", configRequestReason)
 	}
 
 	return headerTransportLayer{Header: headers, baseTransit: baseTransit}

mmv1/third_party/terraform/utils/provider.go.erb

@@ -9,7 +9,8 @@ import (
 
 	"github.com/hashicorp/terraform-plugin-sdk/v2/diag"
 	"github.com/hashicorp/terraform-plugin-sdk/v2/helper/schema"
-
+	"github.com/hashicorp/terraform-provider-google/version"
+
 	googleoauth "golang.org/x/oauth2/google"
 )
 
@@ -138,6 +139,14 @@ func Provider() *schema.Provider {
 			    Optional: true,
 			},
 
+			"request_reason": {
+				Type:     schema.TypeString,
+				Optional: true,
+				DefaultFunc: schema.MultiEnvDefaultFunc([]string{
+					"CLOUDSDK_CORE_REQUEST_REASON",
+				}, nil),
+			},
+
 			// Generated Products
 			<% products.each do |product| -%>
 			"<%= product[:definitions].name.underscore -%>_custom_endpoint": &schema.Schema{
@@ -530,6 +539,10 @@ func providerConfigure(ctx context.Context, d *schema.ResourceData, p *schema.Pr
 		}
 	}
 
+	if v, ok := d.GetOk("request_reason"); ok {
+		config.RequestReason = v.(string)
+	}	
+
 	// Search for default credentials
 	config.Credentials = multiEnvSearch([]string{
 		"GOOGLE_CREDENTIALS",

mmv1/third_party/terraform/website/docs/guides/provider_reference.html.markdown

@@ -148,6 +148,8 @@ the provider should wait for a single HTTP request.  This will not adjust the
 amount of time the provider will wait for a logical operation - use the resource
 timeout blocks for that.
 
+* `request_reason` - (Optional) Send a Request Reason [System Parameter](https://cloud.google.com/apis/docs/system-parameters) for each API call made by the provider.  The `X-Goog-Request-Reason` header value is used to provide a user-supplied justification into GCP AuditLogs. The value set within the provider is overridden if `CLOUDSDK_CORE_REQUEST_REASON` environment variable is used.
+
 The `batching` fields supports:
 
 * `send_after` - (Optional) A duration string representing the amount of time
@@ -266,6 +268,8 @@ an access token using the service account key specified in `credentials`.
     * https://www.googleapis.com/auth/devstorage.full_control
     * https://www.googleapis.com/auth/userinfo.email
 
+* `request_reason` - (Optional) Send a Request Reason [System Parameter](https://cloud.google.com/apis/docs/system-parameters) for each API call made by the provider.  The `X-Goog-Request-Reason` header value is used to provide a user-supplied justification into GCP AuditLogs. Alternatively, this can be specified using the `CLOUDSDK_CORE_REQUEST_REASON` environment variable.
+
 ---
 
 * `{{service}}_custom_endpoint` - (Optional) The endpoint for a service's APIs,