config: move testing shims to BuilderOpts

And remove the devMode field from builder.

This change helps make the Builder state more explicit by moving inputs to the BuilderOps struct,
leaving only fields that can change during Builder.Build on the Builder struct.

agent/config/builder.go

@@ -92,8 +92,7 @@ func Load(opts BuilderOpts, extraHead Source, overrides ...Source) (*RuntimeConf
 // since not all pre-conditions have to be satisfied when performing
 // syntactical tests.
 type Builder struct {
-	// devMode stores the value of the -dev flag, and enables development mode.
-	devMode *bool
+	opts BuilderOpts
 
 	// Head, Sources, and Tail are used to manage the order of the
 	// config sources, as described in the comments above.
@@ -105,15 +104,6 @@ type Builder struct {
 	// parsing the configuration.
 	Warnings []string
 
-	// hostname is a shim for testing, allowing tests to specify a replacement
-	// for os.Hostname.
-	hostname func() (string, error)
-
-	// getPrivateIPv4 and getPublicIPv6 are shims for testing, allowing tests to
-	// specify a replacement for ipaddr.GetPrivateIPv4 and ipaddr.GetPublicIPv6.
-	getPrivateIPv4 func() ([]*net.IPAddr, error)
-	getPublicIPv6  func() ([]*net.IPAddr, error)
-
 	// err contains the first error that occurred during
 	// building the runtime configuration.
 	err error
@@ -135,8 +125,8 @@ func NewBuilder(opts BuilderOpts) (*Builder, error) {
 	}
 
 	b := &Builder{
-		devMode: opts.DevMode,
-		Head:    []Source{DefaultSource(), DefaultEnterpriseSource()},
+		opts: opts,
+		Head: []Source{DefaultSource(), DefaultEnterpriseSource()},
 	}
 
 	if b.boolVal(opts.DevMode) {
@@ -467,14 +457,14 @@ func (b *Builder) Build() (rt RuntimeConfig, err error) {
 		switch {
 		case ipaddr.IsAnyV4(advertiseAddr):
 			addrtyp = "private IPv4"
-			detect = b.getPrivateIPv4
+			detect = b.opts.getPrivateIPv4
 			if detect == nil {
 				detect = ipaddr.GetPrivateIPv4
 			}
 
 		case ipaddr.IsAnyV6(advertiseAddr):
 			addrtyp = "public IPv6"
-			detect = b.getPublicIPv6
+			detect = b.opts.getPublicIPv6
 			if detect == nil {
 				detect = ipaddr.GetPublicIPv6
 			}
@@ -994,7 +984,7 @@ func (b *Builder) Build() (rt RuntimeConfig, err error) {
 		DataDir:                                dataDir,
 		Datacenter:                             datacenter,
 		DefaultQueryTime:                       b.durationVal("default_query_time", c.DefaultQueryTime),
-		DevMode:                                b.boolVal(b.devMode),
+		DevMode:                                b.boolVal(b.opts.DevMode),
 		DisableAnonymousSignature:              b.boolVal(c.DisableAnonymousSignature),
 		DisableCoordinates:                     b.boolVal(c.DisableCoordinates),
 		DisableHostNodeID:                      b.boolVal(c.DisableHostNodeID),
@@ -1900,7 +1890,7 @@ func (b *Builder) tlsCipherSuites(name string, v *string) []uint16 {
 func (b *Builder) nodeName(v *string) string {
 	nodeName := b.stringVal(v)
 	if nodeName == "" {
-		fn := b.hostname
+		fn := b.opts.hostname
 		if fn == nil {
 			fn = os.Hostname
 		}

agent/config/builder_test.go

@@ -172,13 +172,13 @@ func TestBuilder_BuildAndValidate_NodeName(t *testing.T) {
 }
 
 func patchBuilderShims(b *Builder) {
-	b.hostname = func() (string, error) {
+	b.opts.hostname = func() (string, error) {
 		return "thehostname", nil
 	}
-	b.getPrivateIPv4 = func() ([]*net.IPAddr, error) {
+	b.opts.getPrivateIPv4 = func() ([]*net.IPAddr, error) {
 		return []*net.IPAddr{ipAddr("10.0.0.1")}, nil
 	}
-	b.getPublicIPv6 = func() ([]*net.IPAddr, error) {
+	b.opts.getPublicIPv6 = func() ([]*net.IPAddr, error) {
 		return []*net.IPAddr{ipAddr("dead:beef::1")}, nil
 	}
 }

agent/config/flags.go

@@ -3,6 +3,7 @@ package config
 import (
 	"flag"
 	"fmt"
+	"net"
 	"time"
 )
 
@@ -26,6 +27,15 @@ type BuilderOpts struct {
 
 	// HCL contains an arbitrary config in hcl format.
 	HCL []string
+
+	// hostname is a shim for testing, allowing tests to specify a replacement
+	// for os.Hostname.
+	hostname func() (string, error)
+
+	// getPrivateIPv4 and getPublicIPv6 are shims for testing, allowing tests to
+	// specify a replacement for ipaddr.GetPrivateIPv4 and ipaddr.GetPublicIPv6.
+	getPrivateIPv4 func() ([]*net.IPAddr, error)
+	getPublicIPv6  func() ([]*net.IPAddr, error)
 }
 
 // AddFlags adds the command line flags for the agent.

agent/config/runtime_test.go

@@ -4886,13 +4886,13 @@ func testConfig(t *testing.T, tests []configTest, dataDir string) {
 
 				patchBuilderShims(b)
 				if tt.hostname != nil {
-					b.hostname = tt.hostname
+					b.opts.hostname = tt.hostname
 				}
 				if tt.privatev4 != nil {
-					b.getPrivateIPv4 = tt.privatev4
+					b.opts.getPrivateIPv4 = tt.privatev4
 				}
 				if tt.publicv6 != nil {
-					b.getPublicIPv6 = tt.publicv6
+					b.opts.getPublicIPv6 = tt.publicv6
 				}
 
 				// read the source fragements
@@ -4937,9 +4937,7 @@ func testConfig(t *testing.T, tests []configTest, dataDir string) {
 				if err != nil {
 					t.Fatal(err)
 				}
-				x.hostname = b.hostname
-				x.getPrivateIPv4 = func() ([]*net.IPAddr, error) { return []*net.IPAddr{ipAddr("10.0.0.1")}, nil }
-				x.getPublicIPv6 = func() ([]*net.IPAddr, error) { return []*net.IPAddr{ipAddr("dead:beef::1")}, nil }
+				patchBuilderShims(x)
 				expected, err := x.Build()
 				if err != nil {
 					t.Fatalf("build default failed: %s", err)