daemon split (7/n): narrow capability interfaces, wire deps at construction

Stop passing *Daemon into capability hooks. Each capability
implementation is now a struct with explicit service-pointer fields
populated at wireServices time; the six dynamic-dispatch interfaces
(AddStartPreflight, PrepareHost, PostStart, Cleanup, ApplyConfigChange,
AddDoctorChecks) no longer have a *Daemon parameter. Capability
methods reach their dependencies through struct fields, not through
d.vm / d.ws / d.net.

- workDiskCapability carries {vm, ws, store, defaultImageName}
- dnsCapability carries {net}
- natCapability carries {vm, net, logger}

Daemon.defaultCapabilities() builds the production list from the
already-constructed services and is called from wireServices so
d.vmCaps is populated eagerly. Tests that preinstall d.vmCaps with
stubs still work — wireServices only overwrites an empty slice.

registeredCapabilities() is gone (every dispatch loop now reads
d.vmCaps directly). capabilities_test.go's testCapability fake drops
*Daemon from its method set to match the new interfaces.

This finishes the daemon service split: capability implementations
no longer reach through the composition root, there's no path back
to *Daemon from any service or capability, and test construction
goes through one explicit wireServices call instead of lazy getters.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Thales Maciel 2026-04-21 15:59:09 -03:00
parent 16702bd5e1
commit 9c73155e17
No known key found for this signature in database
GPG key ID: 33112E6833C34679
4 changed files with 143 additions and 90 deletions

View file

@ -3,6 +3,7 @@ package daemon
import (
"context"
"errors"
"log/slog"
"net"
"os"
"strings"
@ -10,16 +11,23 @@ import (
"banger/internal/firecracker"
"banger/internal/guestconfig"
"banger/internal/model"
"banger/internal/store"
"banger/internal/system"
"banger/internal/vmdns"
)
// vmCapability is the base capability tag. Actual behaviour lives on
// optional sub-interfaces (startPreflight / guestConfig / machineConfig
// / prepareHost / postStart / cleanup / configChange / doctor); a
// capability implements whichever subset it cares about. None of them
// take *Daemon — each capability is a struct constructed with its
// explicit service-pointer dependencies at wireServices time.
type vmCapability interface {
Name() string
}
type startPreflightCapability interface {
AddStartPreflight(context.Context, *Daemon, *system.Preflight, model.VMRecord, model.Image)
AddStartPreflight(context.Context, *system.Preflight, model.VMRecord, model.Image)
}
type guestConfigCapability interface {
@ -31,46 +39,48 @@ type machineConfigCapability interface {
}
type prepareHostCapability interface {
PrepareHost(context.Context, *Daemon, *model.VMRecord, model.Image) error
PrepareHost(context.Context, *model.VMRecord, model.Image) error
}
type postStartCapability interface {
PostStart(context.Context, *Daemon, model.VMRecord, model.Image) error
PostStart(context.Context, model.VMRecord, model.Image) error
}
type cleanupCapability interface {
Cleanup(context.Context, *Daemon, model.VMRecord) error
Cleanup(context.Context, model.VMRecord) error
}
type configChangeCapability interface {
ApplyConfigChange(context.Context, *Daemon, model.VMRecord, model.VMRecord) error
ApplyConfigChange(context.Context, model.VMRecord, model.VMRecord) error
}
type doctorCapability interface {
AddDoctorChecks(context.Context, *Daemon, *system.Report)
AddDoctorChecks(context.Context, *system.Report)
}
func (d *Daemon) registeredCapabilities() []vmCapability {
if len(d.vmCaps) > 0 {
return d.vmCaps
}
// defaultCapabilities builds the production capability list from
// already-constructed services. Called from wireServices once d.vm /
// d.ws / d.net are populated, so every capability ships with the
// concrete service pointers it needs and none of them reach through
// *Daemon at dispatch time.
func (d *Daemon) defaultCapabilities() []vmCapability {
return []vmCapability{
workDiskCapability{},
dnsCapability{},
natCapability{},
newWorkDiskCapability(d.vm, d.ws, d.store, d.config.DefaultImageName),
newDNSCapability(d.net),
newNATCapability(d.vm, d.net, d.logger),
}
}
func (d *Daemon) addCapabilityStartPrereqs(ctx context.Context, checks *system.Preflight, vm model.VMRecord, image model.Image) {
for _, capability := range d.registeredCapabilities() {
for _, capability := range d.vmCaps {
if hook, ok := capability.(startPreflightCapability); ok {
hook.AddStartPreflight(ctx, d, checks, vm, image)
hook.AddStartPreflight(ctx, checks, vm, image)
}
}
}
func (d *Daemon) contributeGuestConfig(builder *guestconfig.Builder, vm model.VMRecord, image model.Image) {
for _, capability := range d.registeredCapabilities() {
for _, capability := range d.vmCaps {
if hook, ok := capability.(guestConfigCapability); ok {
hook.ContributeGuest(builder, vm, image)
}
@ -78,7 +88,7 @@ func (d *Daemon) contributeGuestConfig(builder *guestconfig.Builder, vm model.VM
}
func (d *Daemon) contributeMachineConfig(cfg *firecracker.MachineConfig, vm model.VMRecord, image model.Image) {
for _, capability := range d.registeredCapabilities() {
for _, capability := range d.vmCaps {
if hook, ok := capability.(machineConfigCapability); ok {
hook.ContributeMachine(cfg, vm, image)
}
@ -86,13 +96,13 @@ func (d *Daemon) contributeMachineConfig(cfg *firecracker.MachineConfig, vm mode
}
func (d *Daemon) prepareCapabilityHosts(ctx context.Context, vm *model.VMRecord, image model.Image) error {
prepared := make([]vmCapability, 0, len(d.registeredCapabilities()))
for _, capability := range d.registeredCapabilities() {
prepared := make([]vmCapability, 0, len(d.vmCaps))
for _, capability := range d.vmCaps {
hook, ok := capability.(prepareHostCapability)
if !ok {
continue
}
if err := hook.PrepareHost(ctx, d, vm, image); err != nil {
if err := hook.PrepareHost(ctx, vm, image); err != nil {
d.cleanupPreparedCapabilities(context.Background(), vm, prepared)
return err
}
@ -102,7 +112,7 @@ func (d *Daemon) prepareCapabilityHosts(ctx context.Context, vm *model.VMRecord,
}
func (d *Daemon) postStartCapabilities(ctx context.Context, vm model.VMRecord, image model.Image) error {
for _, capability := range d.registeredCapabilities() {
for _, capability := range d.vmCaps {
switch capability.Name() {
case "dns":
vmCreateStage(ctx, "apply_dns", "publishing vm dns record")
@ -112,7 +122,7 @@ func (d *Daemon) postStartCapabilities(ctx context.Context, vm model.VMRecord, i
}
}
if hook, ok := capability.(postStartCapability); ok {
if err := hook.PostStart(ctx, d, vm, image); err != nil {
if err := hook.PostStart(ctx, vm, image); err != nil {
return err
}
}
@ -121,7 +131,7 @@ func (d *Daemon) postStartCapabilities(ctx context.Context, vm model.VMRecord, i
}
func (d *Daemon) cleanupCapabilityState(ctx context.Context, vm model.VMRecord) error {
return d.cleanupPreparedCapabilities(ctx, &vm, d.registeredCapabilities())
return d.cleanupPreparedCapabilities(ctx, &vm, d.vmCaps)
}
func (d *Daemon) cleanupPreparedCapabilities(ctx context.Context, vm *model.VMRecord, capabilities []vmCapability) error {
@ -131,15 +141,15 @@ func (d *Daemon) cleanupPreparedCapabilities(ctx context.Context, vm *model.VMRe
if !ok {
continue
}
err = joinErr(err, hook.Cleanup(ctx, d, *vm))
err = joinErr(err, hook.Cleanup(ctx, *vm))
}
return err
}
func (d *Daemon) applyCapabilityConfigChanges(ctx context.Context, before, after model.VMRecord) error {
for _, capability := range d.registeredCapabilities() {
for _, capability := range d.vmCaps {
if hook, ok := capability.(configChangeCapability); ok {
if err := hook.ApplyConfigChange(ctx, d, before, after); err != nil {
if err := hook.ApplyConfigChange(ctx, before, after); err != nil {
return err
}
}
@ -148,18 +158,37 @@ func (d *Daemon) applyCapabilityConfigChanges(ctx context.Context, before, after
}
func (d *Daemon) addCapabilityDoctorChecks(ctx context.Context, report *system.Report) {
for _, capability := range d.registeredCapabilities() {
for _, capability := range d.vmCaps {
if hook, ok := capability.(doctorCapability); ok {
hook.AddDoctorChecks(ctx, d, report)
hook.AddDoctorChecks(ctx, report)
}
}
}
type workDiskCapability struct{}
// workDiskCapability provisions a per-VM work disk (image-seeded or
// freshly formatted) and syncs host-side authorised keys + git
// identity + file_sync entries onto it. Holds pointers to the VM and
// workspace services because PrepareHost orchestrates across both,
// plus the store + default image name for its doctor check.
type workDiskCapability struct {
vm *VMService
ws *WorkspaceService
store *store.Store
defaultImageName string
}
func newWorkDiskCapability(vm *VMService, ws *WorkspaceService, st *store.Store, defaultImageName string) workDiskCapability {
return workDiskCapability{
vm: vm,
ws: ws,
store: st,
defaultImageName: defaultImageName,
}
}
func (workDiskCapability) Name() string { return "work-disk" }
func (workDiskCapability) AddStartPreflight(_ context.Context, _ *Daemon, checks *system.Preflight, vm model.VMRecord, image model.Image) {
func (workDiskCapability) AddStartPreflight(_ context.Context, checks *system.Preflight, vm model.VMRecord, image model.Image) {
if exists(vm.Runtime.WorkDiskPath) {
return
}
@ -198,23 +227,23 @@ func (workDiskCapability) ContributeMachine(cfg *firecracker.MachineConfig, vm m
})
}
func (workDiskCapability) PrepareHost(ctx context.Context, d *Daemon, vm *model.VMRecord, image model.Image) error {
prep, err := d.vm.ensureWorkDisk(ctx, vm, image)
func (c workDiskCapability) PrepareHost(ctx context.Context, vm *model.VMRecord, image model.Image) error {
prep, err := c.vm.ensureWorkDisk(ctx, vm, image)
if err != nil {
return err
}
if err := d.ws.ensureAuthorizedKeyOnWorkDisk(ctx, vm, image, prep); err != nil {
if err := c.ws.ensureAuthorizedKeyOnWorkDisk(ctx, vm, image, prep); err != nil {
return err
}
if err := d.ws.ensureGitIdentityOnWorkDisk(ctx, vm); err != nil {
if err := c.ws.ensureGitIdentityOnWorkDisk(ctx, vm); err != nil {
return err
}
return d.ws.runFileSync(ctx, vm)
return c.ws.runFileSync(ctx, vm)
}
func (workDiskCapability) AddDoctorChecks(_ context.Context, d *Daemon, report *system.Report) {
if d.store != nil && strings.TrimSpace(d.config.DefaultImageName) != "" {
if image, err := d.store.GetImageByName(context.Background(), d.config.DefaultImageName); err == nil && strings.TrimSpace(image.WorkSeedPath) != "" && exists(image.WorkSeedPath) {
func (c workDiskCapability) AddDoctorChecks(_ context.Context, report *system.Report) {
if c.store != nil && strings.TrimSpace(c.defaultImageName) != "" {
if image, err := c.store.GetImageByName(context.Background(), c.defaultImageName); err == nil && strings.TrimSpace(image.WorkSeedPath) != "" && exists(image.WorkSeedPath) {
checks := system.NewPreflight()
checks.RequireFile(image.WorkSeedPath, "default image work-seed", `rebuild the default image to regenerate the /root seed`)
report.AddPreflight("feature /root work disk", checks, "seeded /root work disk artifact available")
@ -229,19 +258,27 @@ func (workDiskCapability) AddDoctorChecks(_ context.Context, d *Daemon, report *
report.AddWarn("feature /root work disk", "default image has no work-seed artifact; new VM creates will be slower until the image is rebuilt")
}
type dnsCapability struct{}
// dnsCapability publishes + removes <vm>.vm records on the in-process
// DNS server. Only needs HostNetwork.
type dnsCapability struct {
net *HostNetwork
}
func newDNSCapability(net *HostNetwork) dnsCapability {
return dnsCapability{net: net}
}
func (dnsCapability) Name() string { return "dns" }
func (dnsCapability) PostStart(ctx context.Context, d *Daemon, vm model.VMRecord, _ model.Image) error {
return d.net.setDNS(ctx, vm.Name, vm.Runtime.GuestIP)
func (c dnsCapability) PostStart(ctx context.Context, vm model.VMRecord, _ model.Image) error {
return c.net.setDNS(ctx, vm.Name, vm.Runtime.GuestIP)
}
func (dnsCapability) Cleanup(_ context.Context, d *Daemon, vm model.VMRecord) error {
return d.net.removeDNS(vm.Runtime.DNSName)
func (c dnsCapability) Cleanup(_ context.Context, vm model.VMRecord) error {
return c.net.removeDNS(vm.Runtime.DNSName)
}
func (dnsCapability) AddDoctorChecks(_ context.Context, _ *Daemon, report *system.Report) {
func (dnsCapability) AddDoctorChecks(_ context.Context, report *system.Report) {
conn, err := net.ListenPacket("udp", vmdns.DefaultListenAddr)
if err != nil {
if strings.Contains(strings.ToLower(err.Error()), "address already in use") {
@ -255,57 +292,69 @@ func (dnsCapability) AddDoctorChecks(_ context.Context, _ *Daemon, report *syste
report.AddPass("feature vm dns", "listener can bind "+vmdns.DefaultListenAddr)
}
type natCapability struct{}
// natCapability sets up host-side NAT so guest traffic can reach the
// outside world. Needs VMService (tap lookup + aliveness) and
// HostNetwork (NAT rules), plus the daemon logger for the cleanup
// short-circuit note.
type natCapability struct {
vm *VMService
net *HostNetwork
logger *slog.Logger
}
func newNATCapability(vm *VMService, net *HostNetwork, logger *slog.Logger) natCapability {
return natCapability{vm: vm, net: net, logger: logger}
}
func (natCapability) Name() string { return "nat" }
func (natCapability) AddStartPreflight(ctx context.Context, d *Daemon, checks *system.Preflight, vm model.VMRecord, _ model.Image) {
func (c natCapability) AddStartPreflight(ctx context.Context, checks *system.Preflight, vm model.VMRecord, _ model.Image) {
if !vm.Spec.NATEnabled {
return
}
d.net.addNATPrereqs(ctx, checks)
c.net.addNATPrereqs(ctx, checks)
}
func (natCapability) PostStart(ctx context.Context, d *Daemon, vm model.VMRecord, _ model.Image) error {
func (c natCapability) PostStart(ctx context.Context, vm model.VMRecord, _ model.Image) error {
if !vm.Spec.NATEnabled {
return nil
}
return d.net.ensureNAT(ctx, vm.Runtime.GuestIP, d.vm.vmHandles(vm.ID).TapDevice, true)
return c.net.ensureNAT(ctx, vm.Runtime.GuestIP, c.vm.vmHandles(vm.ID).TapDevice, true)
}
func (natCapability) Cleanup(ctx context.Context, d *Daemon, vm model.VMRecord) error {
func (c natCapability) Cleanup(ctx context.Context, vm model.VMRecord) error {
if !vm.Spec.NATEnabled {
return nil
}
tap := d.vm.vmHandles(vm.ID).TapDevice
tap := c.vm.vmHandles(vm.ID).TapDevice
if strings.TrimSpace(vm.Runtime.GuestIP) == "" || strings.TrimSpace(tap) == "" {
if d.logger != nil {
d.logger.Debug("skipping nat cleanup without runtime network handles", append(vmLogAttrs(vm), "guest_ip", vm.Runtime.GuestIP, "tap_device", tap)...)
if c.logger != nil {
c.logger.Debug("skipping nat cleanup without runtime network handles", append(vmLogAttrs(vm), "guest_ip", vm.Runtime.GuestIP, "tap_device", tap)...)
}
return nil
}
return d.net.ensureNAT(ctx, vm.Runtime.GuestIP, tap, false)
return c.net.ensureNAT(ctx, vm.Runtime.GuestIP, tap, false)
}
func (natCapability) ApplyConfigChange(ctx context.Context, d *Daemon, before, after model.VMRecord) error {
func (c natCapability) ApplyConfigChange(ctx context.Context, before, after model.VMRecord) error {
if before.Spec.NATEnabled == after.Spec.NATEnabled {
return nil
}
if !d.vm.vmAlive(after) {
if !c.vm.vmAlive(after) {
return nil
}
return d.net.ensureNAT(ctx, after.Runtime.GuestIP, d.vm.vmHandles(after.ID).TapDevice, after.Spec.NATEnabled)
return c.net.ensureNAT(ctx, after.Runtime.GuestIP, c.vm.vmHandles(after.ID).TapDevice, after.Spec.NATEnabled)
}
func (natCapability) AddDoctorChecks(ctx context.Context, d *Daemon, report *system.Report) {
func (c natCapability) AddDoctorChecks(ctx context.Context, report *system.Report) {
checks := system.NewPreflight()
checks.RequireCommand("ip", toolHint("ip"))
d.net.addNATPrereqs(ctx, checks)
c.net.addNATPrereqs(ctx, checks)
if len(checks.Problems()) > 0 {
report.Add(system.CheckStatusFail, "feature nat", checks.Problems()...)
return
}
uplink, err := d.net.defaultUplink(ctx)
uplink, err := c.net.defaultUplink(ctx)
if err != nil {
report.AddFail("feature nat", err.Error())
return

View file

@ -14,27 +14,27 @@ import (
type testCapability struct {
name string
prepare func(context.Context, *Daemon, *model.VMRecord, model.Image) error
cleanup func(context.Context, *Daemon, model.VMRecord) error
prepare func(context.Context, *model.VMRecord, model.Image) error
cleanup func(context.Context, model.VMRecord) error
contribute func(*guestconfig.Builder, model.VMRecord, model.Image)
contributeFC func(*firecracker.MachineConfig, model.VMRecord, model.Image)
configChange func(context.Context, *Daemon, model.VMRecord, model.VMRecord) error
doctor func(context.Context, *Daemon, *system.Report)
startPreflight func(context.Context, *Daemon, *system.Preflight, model.VMRecord, model.Image)
configChange func(context.Context, model.VMRecord, model.VMRecord) error
doctor func(context.Context, *system.Report)
startPreflight func(context.Context, *system.Preflight, model.VMRecord, model.Image)
}
func (c testCapability) Name() string { return c.name }
func (c testCapability) PrepareHost(ctx context.Context, d *Daemon, vm *model.VMRecord, image model.Image) error {
func (c testCapability) PrepareHost(ctx context.Context, vm *model.VMRecord, image model.Image) error {
if c.prepare != nil {
return c.prepare(ctx, d, vm, image)
return c.prepare(ctx, vm, image)
}
return nil
}
func (c testCapability) Cleanup(ctx context.Context, d *Daemon, vm model.VMRecord) error {
func (c testCapability) Cleanup(ctx context.Context, vm model.VMRecord) error {
if c.cleanup != nil {
return c.cleanup(ctx, d, vm)
return c.cleanup(ctx, vm)
}
return nil
}
@ -51,22 +51,22 @@ func (c testCapability) ContributeMachine(cfg *firecracker.MachineConfig, vm mod
}
}
func (c testCapability) ApplyConfigChange(ctx context.Context, d *Daemon, before, after model.VMRecord) error {
func (c testCapability) ApplyConfigChange(ctx context.Context, before, after model.VMRecord) error {
if c.configChange != nil {
return c.configChange(ctx, d, before, after)
return c.configChange(ctx, before, after)
}
return nil
}
func (c testCapability) AddDoctorChecks(ctx context.Context, d *Daemon, report *system.Report) {
func (c testCapability) AddDoctorChecks(ctx context.Context, report *system.Report) {
if c.doctor != nil {
c.doctor(ctx, d, report)
c.doctor(ctx, report)
}
}
func (c testCapability) AddStartPreflight(ctx context.Context, d *Daemon, checks *system.Preflight, vm model.VMRecord, image model.Image) {
func (c testCapability) AddStartPreflight(ctx context.Context, checks *system.Preflight, vm model.VMRecord, image model.Image) {
if c.startPreflight != nil {
c.startPreflight(ctx, d, checks, vm, image)
c.startPreflight(ctx, checks, vm, image)
}
}
@ -78,27 +78,27 @@ func TestPrepareCapabilityHostsRollsBackPreparedCapabilitiesInReverseOrder(t *te
vmCaps: []vmCapability{
testCapability{
name: "first",
prepare: func(context.Context, *Daemon, *model.VMRecord, model.Image) error {
prepare: func(context.Context, *model.VMRecord, model.Image) error {
return nil
},
cleanup: func(context.Context, *Daemon, model.VMRecord) error {
cleanup: func(context.Context, model.VMRecord) error {
cleanupOrder = append(cleanupOrder, "first")
return nil
},
},
testCapability{
name: "second",
prepare: func(context.Context, *Daemon, *model.VMRecord, model.Image) error {
prepare: func(context.Context, *model.VMRecord, model.Image) error {
return nil
},
cleanup: func(context.Context, *Daemon, model.VMRecord) error {
cleanup: func(context.Context, model.VMRecord) error {
cleanupOrder = append(cleanupOrder, "second")
return nil
},
},
testCapability{
name: "broken",
prepare: func(context.Context, *Daemon, *model.VMRecord, model.Image) error {
prepare: func(context.Context, *model.VMRecord, model.Image) error {
return errors.New("boom")
},
},
@ -146,11 +146,11 @@ func TestContributeHooksPopulateGuestAndMachineConfig(t *testing.T) {
}
}
func TestRegisteredCapabilitiesInOrder(t *testing.T) {
func TestDefaultCapabilitiesInOrder(t *testing.T) {
d := &Daemon{}
wireServices(d)
var names []string
for _, capability := range d.registeredCapabilities() {
for _, capability := range d.vmCaps {
names = append(names, capability.Name())
}
want := []string{"work-disk", "dns", "nat"}

View file

@ -662,6 +662,9 @@ func wireServices(d *Daemon) {
beginOperation: d.beginOperation,
})
}
if len(d.vmCaps) == 0 {
d.vmCaps = d.defaultCapabilities()
}
}
func marshalResultOrError(v any, err error) rpc.Response {

View file

@ -32,10 +32,10 @@ import (
// services remain unexported within the package so nothing outside
// the daemon can see them.
//
// Capability invocation still runs through Daemon because the hook
// interfaces take *Daemon directly. VMService calls back via the
// capHooks seam rather than holding a *Daemon pointer, to keep the
// dependency graph acyclic.
// Capability dispatch goes through the capHooks seam rather than a
// *Daemon pointer, so VMService has no path back to the composition
// root. Daemon.buildCapabilityHooks() populates the seam at wiring
// time with the registered-capabilities loops from capabilities.go.
type VMService struct {
runner system.CommandRunner
logger *slog.Logger
@ -67,10 +67,11 @@ type VMService struct {
guestWaitForSSH func(context.Context, string, string, time.Duration) error
guestDial func(context.Context, string, string) (guestSSHClient, error)
// Capability hook dispatch. Capabilities themselves live on
// *Daemon (their interface takes *Daemon as receiver); VMService
// invokes them via these seams so it doesn't need a *Daemon
// pointer.
// Capability hook dispatch. VMService invokes capabilities via
// these seams, populated by Daemon.buildCapabilityHooks() at
// wiring time. Capability implementations themselves are
// structs with explicit service-pointer fields (see capabilities.go);
// VMService never reaches back to *Daemon.
capHooks capabilityHooks
beginOperation func(name string, attrs ...any) *operationLog