Create a `nomad/structs/config` to break an import cycle.

Flattening and normalizing the various Consul config structures and
services has led to an import cycle.  Break this by creating a new package
that is intended to be terminal in the import DAG.

command/agent/agent_test.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	"github.com/hashicorp/nomad/nomad"
+	cconfig "github.com/hashicorp/nomad/nomad/structs/config"
 )
 
 var nextPort uint32 = 17000
@@ -42,7 +43,7 @@ func makeAgent(t testing.TB, cb func(*Config)) (string, *Agent) {
 		Serf: getPort(),
 	}
 	conf.NodeName = fmt.Sprintf("Node %d", conf.Ports.RPC)
-	conf.Consul = &ConsulConfig{}
+	conf.Consul = &cconfig.ConsulConfig{}
 
 	// Tighten the Serf timing
 	config.SerfConfig.MemberlistConfig.SuspicionMult = 2

command/agent/config.go

@@ -14,6 +14,7 @@ import (
 
 	client "github.com/hashicorp/nomad/client/config"
 	"github.com/hashicorp/nomad/nomad"
+	"github.com/hashicorp/nomad/nomad/structs/config"
 )
 
 // Config is the configuration for the Nomad agent.
@@ -85,7 +86,7 @@ type Config struct {
 	// Consul contains the configuration for the Consul Agent and
 	// parameters necessary to register services, their checks, and
 	// discover the current Nomad servers.
-	Consul *ConsulConfig `mapstructure:"consul"`
+	Consul *config.ConsulConfig `mapstructure:"consul"`
 
 	// NomadConfig is used to override the default config.
 	// This is largly used for testing purposes.
@@ -129,62 +130,6 @@ type AtlasConfig struct {
 	Endpoint string `mapstructure:"endpoint"`
 }
 
-// ConsulConfig contains the configuration information necessary to
-// communicate with a Consul Agent in order to:
-//
-// - Register services and checks with Consul
-//
-// - Bootstrap this Nomad Client with the list of Nomad Servers registered
-//   with Consul
-type ConsulConfig struct {
-
-	// ServerServiceName is the name of the service that Nomad uses to register
-	// servers with Consul
-	ServerServiceName string `mapstructure:"server_service_name"`
-
-	// ClientServiceName is the name of the service that Nomad uses to register
-	// clients with Consul
-	ClientServiceName string `mapstructure:"client_service_name"`
-
-	// AutoRegister determines if Nomad will register the Nomad client and
-	// server agents with Consul
-	AutoRegister bool `mapstructure:"auto_register"`
-
-	// Addr is the address of the local Consul agent
-	Addr string `mapstructure:"addr"`
-
-	// Token is used to provide a per-request ACL token.This options overrides
-	// the agent's default token
-	Token string `mapstructure:"token"`
-
-	// Auth is the information to use for http access to Consul agent
-	Auth string `mapstructure:"auth"`
-
-	// EnableSSL sets the transport scheme to talk to the Consul agent as https
-	EnableSSL bool `mapstructure:"ssl"`
-
-	// VerifySSL enables or disables SSL verification when the transport scheme
-	// for the consul api client is https
-	VerifySSL bool `mapstructure:"verify_ssl"`
-
-	// CAFile is the path to the ca certificate used for Consul communication
-	CAFile string `mapstructure:"ca_file"`
-
-	// CertFile is the path to the certificate for Consul communication
-	CertFile string `mapstructure:"cert_file"`
-
-	// KeyFile is the path to the private key for Consul communication
-	KeyFile string `mapstructure:"key_file"`
-
-	// ServerAutoJoin enables Nomad servers to find peers by querying Consul and
-	// joining them
-	ServerAutoJoin bool `mapstructure:"server_auto_join"`
-
-	// ClientAutoJoin enables Nomad servers to find addresses of Nomad servers
-	// and register with them
-	ClientAutoJoin bool `mapstructure:"client_auto_join"`
-}
-
 // StatsConfig determines behavior of resource usage stats collections
 type StatsConfig struct {
 
@@ -445,9 +390,10 @@ func DefaultConfig() *Config {
 		Addresses:      &Addresses{},
 		AdvertiseAddrs: &AdvertiseAddrs{},
 		Atlas:          &AtlasConfig{},
-		Consul: &ConsulConfig{
+		Consul: &config.ConsulConfig{
 			ServerServiceName: "nomad-server",
 			ClientServiceName: "nomad-client",
+			AutoRegister:      true,
 		},
 		Client: &ClientConfig{
 			Enabled:        false,
@@ -815,52 +761,6 @@ func (a *AtlasConfig) Merge(b *AtlasConfig) *AtlasConfig {
 	return &result
 }
 
-// Merge merges two Consul Configurations together.
-func (a *ConsulConfig) Merge(b *ConsulConfig) *ConsulConfig {
-	result := *a
-
-	if b.ServerServiceName != "" {
-		result.ServerServiceName = b.ServerServiceName
-	}
-	if b.ClientServiceName != "" {
-		result.ClientServiceName = b.ClientServiceName
-	}
-	if b.AutoRegister {
-		result.AutoRegister = true
-	}
-	if b.Addr != "" {
-		result.Addr = b.Addr
-	}
-	if b.Token != "" {
-		result.Token = b.Token
-	}
-	if b.Auth != "" {
-		result.Auth = b.Auth
-	}
-	if b.EnableSSL {
-		result.EnableSSL = true
-	}
-	if b.VerifySSL {
-		result.VerifySSL = true
-	}
-	if b.CAFile != "" {
-		result.CAFile = b.CAFile
-	}
-	if b.CertFile != "" {
-		result.CertFile = b.CertFile
-	}
-	if b.KeyFile != "" {
-		result.KeyFile = b.KeyFile
-	}
-	if b.ServerAutoJoin {
-		result.ServerAutoJoin = true
-	}
-	if b.ClientAutoJoin {
-		result.ClientAutoJoin = true
-	}
-	return &result
-}
-
 func (r *Resources) Merge(b *Resources) *Resources {
 	result := *r
 	if b.CPU != 0 {

command/agent/config_parse.go

@@ -10,6 +10,7 @@ import (
 	"github.com/hashicorp/go-multierror"
 	"github.com/hashicorp/hcl"
 	"github.com/hashicorp/hcl/hcl/ast"
+	"github.com/hashicorp/nomad/nomad/structs/config"
 	"github.com/mitchellh/mapstructure"
 )
 
@@ -586,7 +587,7 @@ func parseAtlas(result **AtlasConfig, list *ast.ObjectList) error {
 	return nil
 }
 
-func parseConsulConfig(result **ConsulConfig, list *ast.ObjectList) error {
+func parseConsulConfig(result **config.ConsulConfig, list *ast.ObjectList) error {
 	list = list.Elem()
 	if len(list.Items) > 1 {
 		return fmt.Errorf("only one 'consul' block allowed")
@@ -621,7 +622,7 @@ func parseConsulConfig(result **ConsulConfig, list *ast.ObjectList) error {
 		return err
 	}
 
-	var consulConfig ConsulConfig
+	var consulConfig config.ConsulConfig
 	if err := mapstructure.WeakDecode(m, &consulConfig); err != nil {
 		return err
 	}

command/agent/config_parse_test.go

@@ -4,6 +4,8 @@ import (
 	"path/filepath"
 	"reflect"
 	"testing"
+
+	"github.com/hashicorp/nomad/nomad/structs/config"
 )
 
 func TestConfig_Parse(t *testing.T) {
@@ -100,7 +102,7 @@ func TestConfig_Parse(t *testing.T) {
 					Join:           true,
 					Endpoint:       "127.0.0.1:1234",
 				},
-				Consul: &ConsulConfig{
+				Consul: &config.ConsulConfig{
 					ServerServiceName: "nomad-server",
 					ClientServiceName: "nomad-client",
 					Addr:              "127.0.0.1:9500",

nomad/structs/config/README.md

@@ -0,0 +1,7 @@
+# Overview
+
+`nomad/structs/config` is a package for configuration `struct`s that are
+shared among packages that needs the same `struct` definitions, but can't
+import each other without creating a cyle.  This `config` package must be
+terminal in the import graph (or very close to terminal in the dependency
+graph).

nomad/structs/config/consul.go

@@ -0,0 +1,103 @@
+package config
+
+// ConsulConfig contains the configuration information necessary to
+// communicate with a Consul Agent in order to:
+//
+// - Register services and checks with Consul
+//
+// - Bootstrap this Nomad Client with the list of Nomad Servers registered
+//   with Consul
+type ConsulConfig struct {
+
+	// ServerServiceName is the name of the service that Nomad uses to register
+	// servers with Consul
+	ServerServiceName string `mapstructure:"server_service_name"`
+
+	// ClientServiceName is the name of the service that Nomad uses to register
+	// clients with Consul
+	ClientServiceName string `mapstructure:"client_service_name"`
+
+	// AutoRegister determines if Nomad will register the Nomad client and
+	// server agents with Consul
+	AutoRegister bool `mapstructure:"auto_register"`
+
+	// Addr is the address of the local Consul agent
+	Addr string `mapstructure:"addr"`
+
+	// Token is used to provide a per-request ACL token.This options overrides
+	// the agent's default token
+	Token string `mapstructure:"token"`
+
+	// Auth is the information to use for http access to Consul agent
+	Auth string `mapstructure:"auth"`
+
+	// EnableSSL sets the transport scheme to talk to the Consul agent as https
+	EnableSSL bool `mapstructure:"ssl"`
+
+	// VerifySSL enables or disables SSL verification when the transport scheme
+	// for the consul api client is https
+	VerifySSL bool `mapstructure:"verify_ssl"`
+
+	// CAFile is the path to the ca certificate used for Consul communication
+	CAFile string `mapstructure:"ca_file"`
+
+	// CertFile is the path to the certificate for Consul communication
+	CertFile string `mapstructure:"cert_file"`
+
+	// KeyFile is the path to the private key for Consul communication
+	KeyFile string `mapstructure:"key_file"`
+
+	// ServerAutoJoin enables Nomad servers to find peers by querying Consul and
+	// joining them
+	ServerAutoJoin bool `mapstructure:"server_auto_join"`
+
+	// ClientAutoJoin enables Nomad servers to find addresses of Nomad servers
+	// and register with them
+	ClientAutoJoin bool `mapstructure:"client_auto_join"`
+}
+
+// Merge merges two Consul Configurations together.
+func (a *ConsulConfig) Merge(b *ConsulConfig) *ConsulConfig {
+	result := *a
+
+	if b.ServerServiceName != "" {
+		result.ServerServiceName = b.ServerServiceName
+	}
+	if b.ClientServiceName != "" {
+		result.ClientServiceName = b.ClientServiceName
+	}
+	if b.AutoRegister {
+		result.AutoRegister = true
+	}
+	if b.Addr != "" {
+		result.Addr = b.Addr
+	}
+	if b.Token != "" {
+		result.Token = b.Token
+	}
+	if b.Auth != "" {
+		result.Auth = b.Auth
+	}
+	if b.EnableSSL {
+		result.EnableSSL = true
+	}
+	if b.VerifySSL {
+		result.VerifySSL = true
+	}
+	if b.CAFile != "" {
+		result.CAFile = b.CAFile
+	}
+	if b.CertFile != "" {
+		result.CertFile = b.CertFile
+	}
+	if b.KeyFile != "" {
+		result.KeyFile = b.KeyFile
+	}
+	if b.ServerAutoJoin {
+		result.ServerAutoJoin = true
+	}
+	if b.ClientAutoJoin {
+		result.ClientAutoJoin = true
+	}
+	return &result
+}