config: Use LiteralSource for some defaults

Using the LiteralSource makes it much easier to find default values, because an IDE reports
the location of a default. With an HCL string they are harder to discover.

Also removes unnecessary mapstructure.Decodes of constant values.

agent/config/builder.go

@@ -165,7 +165,7 @@ func NewBuilder(opts BuilderOpts) (*Builder, error) {
 			Data:   s,
 		})
 	}
-	b.Tail = append(b.Tail, NonUserSource(), DefaultConsulSource(), OverrideEnterpriseSource(), DefaultVersionSource())
+	b.Tail = append(b.Tail, NonUserSource(), DefaultConsulSource(), OverrideEnterpriseSource(), defaultVersionSource())
 	if b.boolVal(opts.DevMode) {
 		b.Tail = append(b.Tail, DevConsulSource())
 	}

agent/config/default.go

@@ -1,13 +1,13 @@
 package config
 
 import (
-	"fmt"
 	"strconv"
 
+	"github.com/hashicorp/raft"
+
 	"github.com/hashicorp/consul/agent/checks"
 	"github.com/hashicorp/consul/agent/consul"
 	"github.com/hashicorp/consul/version"
-	"github.com/hashicorp/raft"
 )
 
 // DefaultSource is the default agent configuration.
@@ -205,22 +205,24 @@ func NonUserSource() Source {
 	}
 }
 
-// VersionSource creates a config source for the version parameters.
+// versionSource creates a config source for the version parameters.
 // This should be merged in the tail since these values are not
 // user configurable.
-// TODO: return a LiteralSource (no decoding) instead of a FileSource
+func versionSource(rev, ver, verPre string) Source {
-func VersionSource(rev, ver, verPre string) Source {
+	return LiteralSource{
-	return FileSource{
+		Name: "version",
-		Name:   "version",
+		Config: Config{
-		Format: "hcl",
+			Revision:          &rev,
-		Data:   fmt.Sprintf(`revision = %q version = %q version_prerelease = %q`, rev, ver, verPre),
+			Version:           &ver,
+			VersionPrerelease: &verPre,
+		},
 	}
 }
 
-// DefaultVersionSource returns the version config source for the embedded
+// defaultVersionSource returns the version config source for the embedded
 // version numbers.
-func DefaultVersionSource() Source {
+func defaultVersionSource() Source {
-	return VersionSource(version.GitCommit, version.Version, version.VersionPrerelease)
+	return versionSource(version.GitCommit, version.Version, version.VersionPrerelease)
 }
 
 // DefaultConsulSource returns the default configuration for the consul agent.
@@ -254,27 +256,18 @@ func DefaultConsulSource() Source {
 
 // DevConsulSource returns the consul agent configuration for the dev mode.
 // This should be merged in the tail after the DefaultConsulSource.
-// TODO: return a LiteralSource (no decoding) instead of a FileSource
 func DevConsulSource() Source {
-	return FileSource{
+	c := Config{}
-		Name:   "consul-dev",
+	c.Consul.Coordinate.UpdatePeriod = strPtr("100ms")
-		Format: "hcl",
+	c.Consul.Raft.ElectionTimeout = strPtr("52ms")
-		Data: `
+	c.Consul.Raft.HeartbeatTimeout = strPtr("35ms")
-		consul = {
+	c.Consul.Raft.LeaderLeaseTimeout = strPtr("20ms")
-			coordinate = {
+	c.Consul.Server.HealthInterval = strPtr("10ms")
-				update_period = "100ms"
+	return LiteralSource{Name: "consul-dev", Config: c}
-			}
+}
-			raft = {
+
-				election_timeout = "52ms"
+func strPtr(v string) *string {
-				heartbeat_timeout = "35ms"
+	return &v
-				leader_lease_timeout = "20ms"
-			}
-			server = {
-				health_interval = "10ms"
-			}
-		}
-	`,
-	}
 }
 
 func DefaultRuntimeConfig(hcl string) *RuntimeConfig {

agent/config/default_oss.go

@@ -5,22 +5,12 @@ package config
 // DefaultEnterpriseSource returns the consul agent configuration for enterprise mode.
 // These can be overridden by the user and therefore this source should be merged in the
 // head and processed before user configuration.
-// TODO: return a LiteralSource (no decoding) instead of a FileSource
 func DefaultEnterpriseSource() Source {
-	return FileSource{
+	return LiteralSource{Name: "enterprise-defaults"}
-		Name:   "enterprise-defaults",
-		Format: "hcl",
-		Data:   ``,
-	}
 }
 
 // OverrideEnterpriseSource returns the consul agent configuration for the enterprise mode.
 // This should be merged in the tail after the DefaultConsulSource.
-// TODO: return a LiteralSource (no decoding) instead of a FileSource
 func OverrideEnterpriseSource() Source {
-	return FileSource{
+	return LiteralSource{Name: "enterprise-overrides"}
-		Name:   "enterprise-overrides",
-		Format: "hcl",
-		Data:   ``,
-	}
 }

agent/config/runtime_test.go

@@ -7205,7 +7205,7 @@ func TestFullConfig(t *testing.T) {
 			}
 			b.Sources = append(b.Sources, FileSource{Name: "full." + format, Data: data, Format: format})
 			b.Tail = append(b.Tail, tail[format]...)
-			b.Tail = append(b.Tail, VersionSource("JNtPSav3", "R909Hblt", "ZT1JOQLn"))
+			b.Tail = append(b.Tail, versionSource("JNtPSav3", "R909Hblt", "ZT1JOQLn"))
 
 			// construct the runtime config
 			rt, err := b.Build()