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agent/service_manager: remove 'defaults' field from serviceConfigWatch 

This field was always read by the same function that populated the field,
so it does not need to be a field. Passing the value as an argument to
functions makes it more obvious where the value comes from, and also reduces
the scope of the variable significantly.
pull/7675/head
Daniel Nephin 2020-04-17 16:50:25 -04:00
parent 93235da253
commit 26291a8482
1 changed files with 29 additions and 34 deletions
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63
agent/service_manager.go
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@ -27,10 +27,11 @@ type ServiceManager struct {
// services tracks all active watches for registered services // services tracks all active watches for registered services
services map[structs.ServiceID]*serviceConfigWatch services map[structs.ServiceID]*serviceConfigWatch
// registerCh is a channel for processing service registrations in the // registerCh is a channel for receiving service registration requests from
// background when watches are notified of changes. All sends and receives // from serviceConfigWatchers.
// must also obey the ctx.Done() channel to avoid a deadlock during // The registrations are handled in the background when watches are notified of
// shutdown. // changes. All sends and receives must also obey the ctx.Done() channel to
// avoid a deadlock during shutdown.
registerCh chan *asyncRegisterRequest registerCh chan *asyncRegisterRequest
// ctx is the shared context for all goroutines launched // ctx is the shared context for all goroutines launched
@ -220,7 +221,6 @@ type serviceRegistration struct {
// service/proxy defaults. // service/proxy defaults.
type serviceConfigWatch struct { type serviceConfigWatch struct {
registration *serviceRegistration registration *serviceRegistration
defaults *structs.ServiceConfigResponse
agent *Agent agent *Agent
registerCh chan<- *asyncRegisterRequest registerCh chan<- *asyncRegisterRequest
@ -239,7 +239,7 @@ type serviceConfigWatch struct {
// NOTE: this is called while holding the Agent.stateLock // NOTE: this is called while holding the Agent.stateLock
func (w *serviceConfigWatch) RegisterAndStart( func (w *serviceConfigWatch) RegisterAndStart(
ctx context.Context, ctx context.Context,
previousDefaults *structs.ServiceConfigResponse, serviceDefaults *structs.ServiceConfigResponse,
waitForCentralConfig bool, waitForCentralConfig bool,
persistServiceConfig bool, persistServiceConfig bool,
wg *sync.WaitGroup, wg *sync.WaitGroup,
@ -251,16 +251,16 @@ func (w *serviceConfigWatch) RegisterAndStart(
// operation. Either way the watcher will end up with something flagged // operation. Either way the watcher will end up with something flagged
// as defaults even if they don't actually reflect actual defaults. // as defaults even if they don't actually reflect actual defaults.
if waitForCentralConfig { if waitForCentralConfig {
if err := w.fetchDefaults(ctx); err != nil { var err error
serviceDefaults, err = w.fetchDefaults(ctx)
if err != nil {
return fmt.Errorf("could not retrieve initial service_defaults config for service %q: %v", service.ID, err) return fmt.Errorf("could not retrieve initial service_defaults config for service %q: %v", service.ID, err)
} }
} else {
w.defaults = previousDefaults
} }
// Merge the local registration with the central defaults and update this service // Merge the local registration with the central defaults and update this service
// in the local state. // in the local state.
merged, err := w.mergeServiceConfig() merged, err := mergeServiceConfig(serviceDefaults, w.registration.service)
if err != nil { if err != nil {
return err return err
} }
@ -272,7 +272,7 @@ func (w *serviceConfigWatch) RegisterAndStart(
service: merged, service: merged,
chkTypes: w.registration.chkTypes, chkTypes: w.registration.chkTypes,
persistService: w.registration.service, persistService: w.registration.service,
persistDefaults: w.defaults, persistDefaults: serviceDefaults,
persist: w.registration.persist, persist: w.registration.persist,
persistServiceConfig: persistServiceConfig, persistServiceConfig: persistServiceConfig,
token: w.registration.token, token: w.registration.token,
@ -289,22 +289,20 @@ func (w *serviceConfigWatch) RegisterAndStart(
} }
// NOTE: this is called while holding the Agent.stateLock // NOTE: this is called while holding the Agent.stateLock
func (w *serviceConfigWatch) fetchDefaults(ctx context.Context) error { func (w *serviceConfigWatch) fetchDefaults(ctx context.Context) (*structs.ServiceConfigResponse, error) {
req := makeConfigRequest(w.agent, w.registration) req := makeConfigRequest(w.agent, w.registration)
raw, _, err := w.agent.cache.Get(ctx, cachetype.ResolvedServiceConfigName, req) raw, _, err := w.agent.cache.Get(ctx, cachetype.ResolvedServiceConfigName, req)
if err != nil { if err != nil {
return err return nil, err
} }
reply, ok := raw.(*structs.ServiceConfigResponse) serviceConfig, ok := raw.(*structs.ServiceConfigResponse)
if !ok { if !ok {
// This should never happen, but we want to protect against panics // This should never happen, but we want to protect against panics
return fmt.Errorf("internal error: response type not correct") return nil, fmt.Errorf("internal error: response type not correct")
} }
return serviceConfig, nil
w.defaults = reply
return nil
} }
// Start starts the config watch and a goroutine to handle updates over the // Start starts the config watch and a goroutine to handle updates over the
@ -381,7 +379,7 @@ func (w *serviceConfigWatch) handleUpdate(ctx context.Context, event cache.Updat
return fmt.Errorf("error watching service config: %v", event.Err) return fmt.Errorf("error watching service config: %v", event.Err)
} }
res, ok := event.Result.(*structs.ServiceConfigResponse) serviceDefaults, ok := event.Result.(*structs.ServiceConfigResponse)
if !ok { if !ok {
return fmt.Errorf("unknown update event type: %T", event) return fmt.Errorf("unknown update event type: %T", event)
} }
@ -393,11 +391,10 @@ func (w *serviceConfigWatch) handleUpdate(ctx context.Context, event cache.Updat
// delivered) the correct config so just ignore this old message. // delivered) the correct config so just ignore this old message.
return nil return nil
} }
w.defaults = res
// Merge the local registration with the central defaults and update this service // Merge the local registration with the central defaults and update this service
// in the local state. // in the local state.
merged, err := w.mergeServiceConfig() merged, err := mergeServiceConfig(serviceDefaults, w.registration.service)
if err != nil { if err != nil {
return err return err
} }
@ -415,7 +412,7 @@ func (w *serviceConfigWatch) handleUpdate(ctx context.Context, event cache.Updat
service: merged, service: merged,
chkTypes: w.registration.chkTypes, chkTypes: w.registration.chkTypes,
persistService: w.registration.service, persistService: w.registration.service,
persistDefaults: w.defaults, persistDefaults: serviceDefaults,
persist: w.registration.persist, persist: w.registration.persist,
persistServiceConfig: true, persistServiceConfig: true,
token: w.registration.token, token: w.registration.token,
@ -484,19 +481,17 @@ func makeConfigRequest(agent *Agent, registration *serviceRegistration) *structs
return req return req
} }
// mergeServiceConfig returns the final effective config for the watched service, // mergeServiceConfig from service into defaults to produce the final effective
// including the latest known global defaults from the servers. // config for the watched service.
// func mergeServiceConfig(defaults *structs.ServiceConfigResponse, service *structs.NodeService) (*structs.NodeService, error) {
// NOTE: this is called while holding the Agent.stateLock if defaults == nil {
func (w *serviceConfigWatch) mergeServiceConfig() (*structs.NodeService, error) { return service, nil
if w.defaults == nil {
return w.registration.service, nil
} }
// We don't want to change s.registration in place since it is our source of // We don't want to change s.registration in place since it is our source of
// truth about what was actually registered before defaults applied. So copy // truth about what was actually registered before defaults applied. So copy
// it first. // it first.
nsRaw, err := copystructure.Copy(w.registration.service) nsRaw, err := copystructure.Copy(service)
if err != nil { if err != nil {
return nil, err return nil, err
} }
@ -504,16 +499,16 @@ func (w *serviceConfigWatch) mergeServiceConfig() (*structs.NodeService, error)
// Merge proxy defaults // Merge proxy defaults
ns := nsRaw.(*structs.NodeService) ns := nsRaw.(*structs.NodeService)
if err := mergo.Merge(&ns.Proxy.Config, w.defaults.ProxyConfig); err != nil { if err := mergo.Merge(&ns.Proxy.Config, defaults.ProxyConfig); err != nil {
return nil, err return nil, err
} }
if err := mergo.Merge(&ns.Proxy.Expose, w.defaults.Expose); err != nil { if err := mergo.Merge(&ns.Proxy.Expose, defaults.Expose); err != nil {
return nil, err return nil, err
} }
if ns.Proxy.MeshGateway.Mode == structs.MeshGatewayModeDefault { if ns.Proxy.MeshGateway.Mode == structs.MeshGatewayModeDefault {
ns.Proxy.MeshGateway.Mode = w.defaults.MeshGateway.Mode ns.Proxy.MeshGateway.Mode = defaults.MeshGateway.Mode
} }
// Merge upstream defaults if there were any returned // Merge upstream defaults if there were any returned
@ -529,7 +524,7 @@ func (w *serviceConfigWatch) mergeServiceConfig() (*structs.NodeService, error)
us.MeshGateway.Mode = ns.Proxy.MeshGateway.Mode us.MeshGateway.Mode = ns.Proxy.MeshGateway.Mode
} }
usCfg, ok := w.defaults.UpstreamIDConfigs.GetUpstreamConfig(us.DestinationID()) usCfg, ok := defaults.UpstreamIDConfigs.GetUpstreamConfig(us.DestinationID())
if !ok { if !ok {
// No config defaults to merge // No config defaults to merge
continue continue