provider/openstack: Add Terraform version to UserAgent string (#14955)

* core: Add 'UserAgentString' helper function to generate a standard UserAgent string. Example generation: 'Terraform 0.9.7-dev (go1.8.1)'

* provider/openstack: Add Terraform version to UserAgent string

builtin/providers/openstack/config.go

@@ -11,6 +11,7 @@ import (
 	"github.com/gophercloud/gophercloud/openstack"
 	"github.com/gophercloud/gophercloud/openstack/objectstorage/v1/swauth"
 	"github.com/hashicorp/terraform/helper/pathorcontents"
+	"github.com/hashicorp/terraform/terraform"
 )
 
 type Config struct {
@@ -69,6 +70,9 @@ func (c *Config) loadAndValidate() error {
 		return err
 	}
 
+	// Set UserAgent
+	client.UserAgent.Prepend(terraform.UserAgentString())
+
 	config := &tls.Config{}
 	if c.CACertFile != "" {
 		caCert, _, err := pathorcontents.Read(c.CACertFile)

terraform/user_agent.go

@@ -0,0 +1,14 @@
+package terraform
+
+import (
+	"fmt"
+	"runtime"
+)
+
+// The standard Terraform User-Agent format
+const UserAgent = "Terraform %s (%s)"
+
+// Generate a UserAgent string
+func UserAgentString() string {
+	return fmt.Sprintf(UserAgent, VersionString(), runtime.Version())
+}