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common.go
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common.go
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// Copyright 2016 Apcera Inc. All rights reserved.
package stores
import (
"fmt"
"sync"
"github.com/nats-io/go-nats-streaming/pb"
"github.com/nats-io/nats-streaming-server/spb"
)
// format string used to report that limit is reached when storing
// messages.
var droppingMsgsFmt = "WARNING: Reached limits for store %q (msgs=%v/%v bytes=%v/%v), " +
"dropping old messages to make room for new ones."
// commonStore contains everything that is common to any type of store
type commonStore struct {
sync.RWMutex
closed bool
}
// genericStore is the generic store implementation with a map of channels.
type genericStore struct {
commonStore
limits StoreLimits
name string
channels map[string]*ChannelStore
clients map[string]*Client
}
// genericSubStore is the generic store implementation that manages subscriptions
// for a given channel.
type genericSubStore struct {
commonStore
limits SubStoreLimits
subject string // Can't be wildcard
subsCount int
maxSubID uint64
}
// genericMsgStore is the generic store implementation that manages messages
// for a given channel.
type genericMsgStore struct {
commonStore
limits MsgStoreLimits
subject string // Can't be wildcard
first uint64
last uint64
totalCount int
totalBytes uint64
hitLimit bool // indicates if store had to drop messages due to limit
}
////////////////////////////////////////////////////////////////////////////
// genericStore methods
////////////////////////////////////////////////////////////////////////////
// init initializes the structure of a generic store
func (gs *genericStore) init(name string, limits *StoreLimits) {
gs.name = name
if limits == nil {
limits = &DefaultStoreLimits
}
gs.setLimits(limits)
// Do not use limits values to create the map.
gs.channels = make(map[string]*ChannelStore)
gs.clients = make(map[string]*Client)
}
// Init can be used to initialize the store with server's information.
func (gs *genericStore) Init(info *spb.ServerInfo) error {
return nil
}
// Name returns the type name of this store
func (gs *genericStore) Name() string {
return gs.name
}
// setLimits makes a copy of the given StoreLimits,
// validates the limits and if ok, applies the inheritance.
func (gs *genericStore) setLimits(limits *StoreLimits) error {
// Make a copy
gs.limits = *limits
// of the map too
if len(limits.PerChannel) > 0 {
gs.limits.PerChannel = make(map[string]*ChannelLimits, len(limits.PerChannel))
for key, val := range limits.PerChannel {
// Make a copy of the values. We want ownership
// of those structures
gs.limits.PerChannel[key] = &(*val)
}
}
// Build will validate and apply inheritance if no error.
sl := &gs.limits
return sl.Build()
}
// SetLimits sets limits for this store
func (gs *genericStore) SetLimits(limits *StoreLimits) error {
gs.Lock()
err := gs.setLimits(limits)
gs.Unlock()
return err
}
// CreateChannel creates a ChannelStore for the given channel, and returns
// `true` to indicate that the channel is new, false if it already exists.
func (gs *genericStore) CreateChannel(channel string, userData interface{}) (*ChannelStore, bool, error) {
// no-op
return nil, false, fmt.Errorf("Generic store, feature not implemented")
}
// LookupChannel returns a ChannelStore for the given channel.
func (gs *genericStore) LookupChannel(channel string) *ChannelStore {
gs.RLock()
cs := gs.channels[channel]
gs.RUnlock()
return cs
}
// HasChannel returns true if this store has any channel
func (gs *genericStore) HasChannel() bool {
gs.RLock()
l := len(gs.channels)
gs.RUnlock()
return l > 0
}
// State returns message store statistics for a given channel ('*' for all)
func (gs *genericStore) MsgsState(channel string) (numMessages int, byteSize uint64, err error) {
numMessages = 0
byteSize = 0
err = nil
if channel == AllChannels {
gs.RLock()
cs := gs.channels
gs.RUnlock()
for _, c := range cs {
n, b, lerr := c.Msgs.State()
if lerr != nil {
err = lerr
return
}
numMessages += n
byteSize += b
}
} else {
cs := gs.LookupChannel(channel)
if cs != nil {
numMessages, byteSize, err = cs.Msgs.State()
}
}
return
}
// canAddChannel returns true if the current number of channels is below the limit.
// Store lock is assumed to be locked.
func (gs *genericStore) canAddChannel() error {
if gs.limits.MaxChannels > 0 && len(gs.channels) >= gs.limits.MaxChannels {
return ErrTooManyChannels
}
return nil
}
// AddClient stores information about the client identified by `clientID`.
func (gs *genericStore) AddClient(clientID, hbInbox string, userData interface{}) (*Client, bool, error) {
c := &Client{spb.ClientInfo{ID: clientID, HbInbox: hbInbox}, userData}
gs.Lock()
oldClient := gs.clients[clientID]
if oldClient != nil {
gs.Unlock()
return oldClient, false, nil
}
gs.clients[c.ID] = c
gs.Unlock()
return c, true, nil
}
// GetClient returns the stored Client, or nil if it does not exist.
func (gs *genericStore) GetClient(clientID string) *Client {
gs.RLock()
c := gs.clients[clientID]
gs.RUnlock()
return c
}
// GetClients returns all stored Client objects, as a map keyed by client IDs.
func (gs *genericStore) GetClients() map[string]*Client {
gs.RLock()
clients := make(map[string]*Client, len(gs.clients))
for k, v := range gs.clients {
clients[k] = v
}
gs.RUnlock()
return clients
}
// GetClientsCount returns the number of registered clients
func (gs *genericStore) GetClientsCount() int {
gs.RLock()
count := len(gs.clients)
gs.RUnlock()
return count
}
// DeleteClient deletes the client identified by `clientID`.
func (gs *genericStore) DeleteClient(clientID string) *Client {
gs.Lock()
c := gs.clients[clientID]
if c != nil {
delete(gs.clients, clientID)
}
gs.Unlock()
return c
}
// Close closes all stores
func (gs *genericStore) Close() error {
gs.Lock()
defer gs.Unlock()
if gs.closed {
return nil
}
gs.closed = true
return gs.close()
}
// close closes all stores. Store lock is assumed held on entry
func (gs *genericStore) close() error {
var err error
var lerr error
for _, cs := range gs.channels {
lerr = cs.Subs.Close()
if lerr != nil && err == nil {
err = lerr
}
lerr = cs.Msgs.Close()
if lerr != nil && err == nil {
err = lerr
}
}
return err
}
////////////////////////////////////////////////////////////////////////////
// genericMsgStore methods
////////////////////////////////////////////////////////////////////////////
// init initializes this generic message store
func (gms *genericMsgStore) init(subject string, limits *MsgStoreLimits) {
gms.subject = subject
gms.limits = *limits
}
// State returns some statistics related to this store
func (gms *genericMsgStore) State() (numMessages int, byteSize uint64, err error) {
gms.RLock()
c, b := gms.totalCount, gms.totalBytes
gms.RUnlock()
return c, b, nil
}
// FirstSequence returns sequence for first message stored.
func (gms *genericMsgStore) FirstSequence() uint64 {
gms.RLock()
first := gms.first
gms.RUnlock()
return first
}
// LastSequence returns sequence for last message stored.
func (gms *genericMsgStore) LastSequence() uint64 {
gms.RLock()
last := gms.last
gms.RUnlock()
return last
}
// FirstAndLastSequence returns sequences for the first and last messages stored.
func (gms *genericMsgStore) FirstAndLastSequence() (uint64, uint64) {
gms.RLock()
first, last := gms.first, gms.last
gms.RUnlock()
return first, last
}
// Lookup returns the stored message with given sequence number.
func (gms *genericMsgStore) Lookup(seq uint64) *pb.MsgProto {
// no-op
return nil
}
// FirstMsg returns the first message stored.
func (gms *genericMsgStore) FirstMsg() *pb.MsgProto {
// no-op
return nil
}
// LastMsg returns the last message stored.
func (gms *genericMsgStore) LastMsg() *pb.MsgProto {
// no-op
return nil
}
func (gms *genericMsgStore) Flush() error {
// no-op
return nil
}
// GetSequenceFromTimestamp returns the sequence of the first message whose
// timestamp is greater or equal to given timestamp.
func (gms *genericMsgStore) GetSequenceFromTimestamp(timestamp int64) uint64 {
// no-op
return 0
}
// Close closes this store.
func (gms *genericMsgStore) Close() error {
return nil
}
////////////////////////////////////////////////////////////////////////////
// genericSubStore methods
////////////////////////////////////////////////////////////////////////////
// init initializes the structure of a generic sub store
func (gss *genericSubStore) init(channel string, limits *SubStoreLimits) {
gss.subject = channel
gss.limits = *limits
}
// CreateSub records a new subscription represented by SubState. On success,
// it records the subscription's ID in SubState.ID. This ID is to be used
// by the other SubStore methods.
func (gss *genericSubStore) CreateSub(sub *spb.SubState) error {
gss.Lock()
err := gss.createSub(sub)
gss.Unlock()
return err
}
// UpdateSub updates a given subscription represented by SubState.
func (gss *genericSubStore) UpdateSub(sub *spb.SubState) error {
return nil
}
// createSub is the unlocked version of CreateSub that can be used by
// non-generic implementations.
func (gss *genericSubStore) createSub(sub *spb.SubState) error {
if gss.limits.MaxSubscriptions > 0 && gss.subsCount >= gss.limits.MaxSubscriptions {
return ErrTooManySubs
}
// Bump the max value before assigning it to the new subscription.
gss.maxSubID++
gss.subsCount++
// This new subscription has the max value.
sub.ID = gss.maxSubID
return nil
}
// DeleteSub invalidates this subscription.
func (gss *genericSubStore) DeleteSub(subid uint64) {
gss.Lock()
gss.subsCount--
gss.Unlock()
}
// AddSeqPending adds the given message seqno to the given subscription.
func (gss *genericSubStore) AddSeqPending(subid, seqno uint64) error {
// no-op
return nil
}
// AckSeqPending records that the given message seqno has been acknowledged
// by the given subscription.
func (gss *genericSubStore) AckSeqPending(subid, seqno uint64) error {
// no-op
return nil
}
// Flush is for stores that may buffer operations and need them to be persisted.
func (gss *genericSubStore) Flush() error {
// no-op
return nil
}
// Close closes this store
func (gss *genericSubStore) Close() error {
// no-op
return nil
}