feat(fleet): add basic fleet configuration to cloud-config

initialize/config.go

@@ -32,6 +32,7 @@ type CloudConfig struct {
 	SSHAuthorizedKeys []string `yaml:"ssh_authorized_keys"`
 	Coreos            struct {
 		Etcd   EtcdEnvironment
+		Fleet  FleetEnvironment
 		OEM    OEMRelease
 		Update UpdateConfig
 		Units  []system.Unit
@@ -133,7 +134,7 @@ func Apply(cfg CloudConfig, env *Environment) error {
 		}
 	}
 
-	for _, ccu := range []CloudConfigUnit{cfg.Coreos.Etcd, cfg.Coreos.Update} {
+	for _, ccu := range []CloudConfigUnit{cfg.Coreos.Etcd, cfg.Coreos.Fleet, cfg.Coreos.Update} {
 		u, err := ccu.Unit(env.Root())
 		if err != nil {
 			return err

initialize/fleet.go

@@ -0,0 +1,34 @@
+package initialize
+
+import (
+	"fmt"
+
+	"github.com/coreos/coreos-cloudinit/system"
+)
+
+type FleetEnvironment map[string]string
+
+func (fe FleetEnvironment) String() (out string) {
+	norm := normalizeSvcEnv(fe)
+	out += "[Service]\n"
+
+	for key, val := range norm {
+		out += fmt.Sprintf("Environment=\"FLEET_%s=%s\"\n", key, val)
+	}
+
+	return
+}
+
+// Unit generates a Unit file drop-in for fleet, if any fleet options were
+// configured in cloud-config
+func (fe FleetEnvironment) Unit(root string) (*system.Unit, error) {
+	if len(fe) < 1 {
+		return nil, nil
+	}
+	return &system.Unit{
+		Name:    "fleet.service",
+		Runtime: true,
+		DropIn:  true,
+		Content: fe.String(),
+	}, nil
+}

initialize/fleet_test.go

@@ -0,0 +1,42 @@
+package initialize
+
+import "testing"
+
+func TestFleetEnvironment(t *testing.T) {
+	cfg := make(FleetEnvironment, 0)
+	cfg["public-ip"] = "12.34.56.78"
+
+	env := cfg.String()
+
+	expect := `[Service]
+Environment="FLEET_PUBLIC_IP=12.34.56.78"
+`
+
+	if env != expect {
+		t.Errorf("Generated environment:\n%s\nExpected environment:\n%s", env, expect)
+	}
+}
+
+func TestFleetUnit(t *testing.T) {
+	cfg := make(FleetEnvironment, 0)
+	u, err := cfg.Unit("/")
+	if u != nil {
+		t.Errorf("unexpectedly generated unit with empty FleetEnvironment")
+	}
+
+	cfg["public-ip"] = "12.34.56.78"
+
+	u, err = cfg.Unit("/")
+	if err != nil {
+		t.Errorf("error generating fleet unit: %v", err)
+	}
+	if u == nil {
+		t.Fatalf("unexpectedly got nil unit generating fleet unit!")
+	}
+	if !u.Runtime {
+		t.Errorf("bad Runtime for generated fleet unit!")
+	}
+	if !u.DropIn {
+		t.Errorf("bad DropIn for generated fleet unit!")
+	}
+}