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use.go
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use.go
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package orc
import (
"sync"
"github.com/sirupsen/logrus"
"github.com/spf13/pflag"
)
type RunContext struct {
modulesBeganUse []*moduleContext
orderedModules []*moduleContext
graph Graph
}
func (r *RunContext) registerEdge(dependent, dependency Module) {
logrus.Debugf("[%p] Dependency: %s --> %s", r, Describe(dependent), Describe(dependency))
r.graph.Edges = append(r.graph.Edges, Edge{
Dependent: dependent,
Dependency: dependency,
})
}
type UseContext struct {
Flags *pflag.FlagSet
runCtx *RunContext
modCtx *moduleContext
originalOpts []Option
alreadyUsed map[Module]bool
}
func (u UseContext) Use(mod Module, newOptions ...Option) {
u.runCtx.registerEdge(u.modCtx.module, mod)
u.modCtx.use(u.runCtx, mod, append(u.originalOpts, newOptions...)...)
}
type ModuleHooks interface {
OnUse(func(UseContext))
OnValidate(func() error)
OnSetup(func() error)
OnTeardown(func() error)
OnStart(func() error)
OnStop(func() error)
}
type hookId string
const (
hookValidate = hookId("validate")
hookSetup = hookId("setup")
hookStart = hookId("start")
hookStop = hookId("stop")
hookTeardown = hookId("teardown")
)
type labelledHook struct {
hookType hookId
hook func() error
}
type moduleContext struct {
reg *Registry
module Module
usehooks []func(UseContext)
hooks []labelledHook
}
func (m *moduleContext) addHook(stage hookId, f func() error) {
logrus.Debugf("Adding hook #%d type=%s to %s (context %p)", len(m.hooks), stage, Describe(m.module), m)
m.hooks = append(m.hooks, labelledHook{stage, f})
}
func (m *moduleContext) OnUse(f func(UseContext)) {
m.usehooks = append(m.usehooks, f)
}
func (m *moduleContext) OnValidate(f func() error) {
m.addHook(hookValidate, f)
}
func (m *moduleContext) OnSetup(f func() error) {
m.addHook(hookSetup, f)
}
func (m *moduleContext) OnTeardown(f func() error) {
m.addHook(hookTeardown, f)
}
func (m *moduleContext) OnStart(f func() error) {
logrus.Debugf("adding start hook to %s", Describe(m.module))
m.addHook(hookStart, f)
}
func (m *moduleContext) OnStop(f func() error) {
m.addHook(hookStop, f)
}
func (m *moduleContext) runUseHooks(ctx UseContext) {
if ctx.alreadyUsed[m.module] {
return
}
for _, f := range m.usehooks {
f(ctx)
}
}
type Registry struct {
mu sync.Mutex
modules map[Module]*moduleContext
}
var (
globalRegistry = &Registry{
modules: map[Module]*moduleContext{},
}
)
func (r *Registry) getContext(module Module, options ...Option) (*moduleContext, bool) {
r.mu.Lock()
defer r.mu.Unlock()
ctx, ok := r.modules[module]
if !ok {
ctx = &moduleContext{
reg: r,
module: module,
}
r.modules[module] = ctx
}
return ctx, ok
}
func (r *Registry) use(runCtx *RunContext, parent Module, module Module, options ...Option) {
// Is the module registered? If not register it, otherwise get its context.
modCtx, wasOld := r.getContext(module)
if !wasOld {
module.OnRegister(modCtx)
}
parsed, err := parseOptions(options)
if err != nil {
Fail(err)
}
useCtx := UseContext{
runCtx: runCtx,
modCtx: modCtx,
originalOpts: options,
alreadyUsed: map[Module]bool{},
}
for _, mod := range runCtx.modulesBeganUse {
useCtx.alreadyUsed[mod.module] = true
}
// Prevent use hooks from running twice when used in the same RunContext.
runCtx.modulesBeganUse = append(runCtx.modulesBeganUse, modCtx)
parsed.intoUseContext(&useCtx)
modCtx.runUseHooks(useCtx)
for _, oldOrderedModule := range runCtx.orderedModules {
if oldOrderedModule == modCtx {
return
}
}
runCtx.orderedModules = append(runCtx.orderedModules, modCtx)
}
func (m *moduleContext) use(runCtx *RunContext, mod Module, options ...Option) {
// TODO check cycles. may be recursive, but not cyclic.
globalRegistry.use(runCtx, m.module, mod, options...)
}
func Use(module Module, options ...Option) *RunContext {
// TODO check this is a top-level call (never recursive)
runCtx := &RunContext{}
logrus.Debugf("[%p] Top-level use: %s", runCtx, Describe(module))
globalRegistry.use(runCtx, nil, module, options...)
return runCtx
}
func (r *RunContext) Run(body func() error) {
if err := globalRegistry.tryRun(r, body); err != nil {
logrus.Fatalf("fatal: %v", err)
}
}
func (r *Registry) tryRun(runCtx *RunContext, body func() error) error {
r.mu.Lock()
defer r.mu.Unlock()
logrus.Debugf("Enumerating Modules in order")
for i, modCtx := range runCtx.orderedModules {
logrus.Debugf("Module %d: %s (context %p)", i, Describe(modCtx.module), modCtx)
}
logrus.Debugf("Running Validate hooks")
// Visit all the modules in order, run their validate hooks.
for _, modCtx := range runCtx.orderedModules {
for i, labelledHook := range modCtx.hooks {
if labelledHook.hookType == hookValidate {
logrus.Debugf("Running Validate hook #%d for %s", i, Describe(modCtx.module))
if err := labelledHook.hook(); err != nil {
return err
}
}
}
}
logrus.Debugf("Running Setup hooks")
// Visit all the modules in order, run setup and defer teardown.
for _, modCtx := range runCtx.orderedModules {
for i, labelledHook := range modCtx.hooks {
if labelledHook.hookType == hookSetup {
logrus.Debugf("Running Setup hook #%d for %s", i, Describe(modCtx.module))
if err := labelledHook.hook(); err != nil {
return err
}
}
if labelledHook.hookType == hookTeardown {
labelledHook := labelledHook
defer func() {
logrus.Debugf("Running Teardown hook")
err := labelledHook.hook()
if err != nil {
logrus.Warningf("teardown error: %v", err)
}
}()
}
}
}
logrus.Debugf("Running Start hooks")
// Visit all the modules in order, run start and defer stop.
for _, modCtx := range runCtx.orderedModules {
for i, labelledHook := range modCtx.hooks {
if labelledHook.hookType == hookStart {
logrus.Debugf("Running Start hook #%d for %s", i, Describe(modCtx.module))
if err := labelledHook.hook(); err != nil {
return err
}
}
if labelledHook.hookType == hookStop {
labelledHook := labelledHook
defer func() {
logrus.Debugf("Running Stop hook")
err := labelledHook.hook()
if err != nil {
logrus.Warningf("stop error: %v", err)
}
}()
}
}
}
return body()
}