// Top-level method to get all the changes in a channel since the sequence 'since'.
// If the cache doesn't go back far enough, the view will be queried.
// View query results may be fed back into the cache if there's room.
// initialSequence is used only if the cache is empty: it gives the max sequence to which the
// view should be queried, because we don't want the view query to outrun the chanceCache's
// nextSequence.
func (c *channelCache) GetChanges(options ChangesOptions) ([]*LogEntry, error) {
// Use the cache, and return if it fulfilled the entire request:
cacheValidFrom, resultFromCache := c.getCachedChanges(options)
numFromCache := len(resultFromCache)
if numFromCache > 0 || resultFromCache == nil {
base.LogTo("Cache", "getCachedChanges(%q, %d) --> %d changes valid from #%d",
c.channelName, options.Since, numFromCache, cacheValidFrom)
} else if resultFromCache == nil {
base.LogTo("Cache", "getCachedChanges(%q, %d) --> nothing cached",
c.channelName, options.Since)
}
if cacheValidFrom <= options.Since+1 {
return resultFromCache, nil
}
// Nope, we're going to have to backfill from the view.
//** First acquire the _view_ lock (not the regular lock!)
c.viewLock.Lock()
defer c.viewLock.Unlock()
// Another goroutine might have gotten the lock first and already queried the view and updated
// the cache, so repeat the above:
cacheValidFrom, resultFromCache = c._getCachedChanges(options)
if len(resultFromCache) > numFromCache {
base.LogTo("Cache", "2nd getCachedChanges(%q, %d) got %d more, valid from #%d!",
c.channelName, options.Since, len(resultFromCache)-numFromCache, cacheValidFrom)
}
if cacheValidFrom <= options.Since+1 {
return resultFromCache, nil
}
// Now query the view. We set the max sequence equal to cacheValidFrom, so we'll get one
// overlap, which helps confirm that we've got everything.
resultFromView, err := c.context.getChangesInChannelFromView(c.channelName, cacheValidFrom,
options)
if err != nil {
return nil, err
}
// Cache some of the view results, if there's room in the cache:
if len(resultFromCache) < ChannelCacheMaxLength {
c.prependChanges(resultFromView, options.Since+1, options.Limit == 0)
}
result := resultFromView
room := options.Limit - len(result)
if (options.Limit == 0 || room > 0) && len(resultFromCache) > 0 {
// Concatenate the view & cache results:
if len(result) > 0 && resultFromCache[0].Sequence == result[len(result)-1].Sequence {
resultFromCache = resultFromCache[1:]
}
n := len(resultFromCache)
if options.Limit > 0 && room > 0 && room < n {
n = room
}
result = append(result, resultFromCache[0:n]...)
}
base.LogTo("Cache", "GetChangesInChannel(%q) --> %d rows", c.channelName, len(result))
return result, nil
}
// Main loop that pulls changes from the external bucket. (Runs in its own goroutine.)
func (s *Shadower) readTapFeed() {
vbucketsFilling := 0
for event := range s.tapFeed.Events() {
switch event.Opcode {
case walrus.TapBeginBackfill:
if vbucketsFilling == 0 {
base.LogTo("Shadow", "Reading history of external bucket")
}
vbucketsFilling++
//base.LogTo("Shadow", "Reading history of external bucket")
case walrus.TapMutation, walrus.TapDeletion:
key := string(event.Key)
// Ignore ephemeral documents or ones whose ID would conflict with our metadata
if event.Expiry > 0 || !s.docIDMatches(key) {
break
}
isDeletion := event.Opcode == walrus.TapDeletion
err := s.pullDocument(key, event.Value, isDeletion, event.Sequence, event.Flags)
if err != nil {
base.Warn("Error applying change from external bucket: %v", err)
}
case walrus.TapEndBackfill:
if vbucketsFilling--; vbucketsFilling == 0 {
base.LogTo("Shadow", "Caught up with history of external bucket")
}
}
}
base.LogTo("Shadow", "End of tap feed(?)")
}
// Main loop that pulls changes from the external bucket. (Runs in its own goroutine.)
func (s *Shadower) readTapFeed() {
vbucketsFilling := 0
for event := range s.tapFeed.Events() {
switch event.Opcode {
case walrus.TapBeginBackfill:
if vbucketsFilling == 0 {
base.LogTo("Shadow", "Reading history of external bucket")
}
vbucketsFilling++
//base.LogTo("Shadow", "Reading history of external bucket")
case walrus.TapMutation, walrus.TapDeletion:
key := string(event.Key)
if !s.docIDMatches(key) {
break
}
isDeletion := event.Opcode == walrus.TapDeletion
if !isDeletion && event.Expiry > 0 {
break // ignore ephemeral documents
}
err := s.pullDocument(key, event.Value, isDeletion, event.Sequence, event.Flags)
if err != nil {
base.Warn("Error applying change from external bucket: %v", err)
}
atomic.AddUint64(&s.pullCount, 1)
case walrus.TapEndBackfill:
if vbucketsFilling--; vbucketsFilling == 0 {
base.LogTo("Shadow", "Caught up with history of external bucket")
}
}
}
base.LogTo("Shadow", "End of tap feed(?)")
}
// Saves a new local revision to the external bucket.
func (s *Shadower) PushRevision(doc *document) {
defer func() { atomic.AddUint64(&s.pushCount, 1) }()
if !s.docIDMatches(doc.ID) {
return
} else if doc.newestRevID() == doc.UpstreamRev {
return // This revision was pulled from the external bucket, so don't push it back!
}
var err error
if doc.Flags&channels.Deleted != 0 {
base.LogTo("Shadow", "Pushing %q, rev %q [deletion]", doc.ID, doc.CurrentRev)
err = s.bucket.Delete(doc.ID)
} else {
base.LogTo("Shadow", "Pushing %q, rev %q", doc.ID, doc.CurrentRev)
body := doc.getRevision(doc.CurrentRev)
if body == nil {
base.Warn("Can't get rev %q.%q to push to external bucket", doc.ID, doc.CurrentRev)
return
}
err = s.bucket.Set(doc.ID, 0, body)
}
if err != nil {
base.Warn("Error pushing rev of %q to external bucket: %v", doc.ID, err)
}
}
func (db *Database) WaitForRevision() bool {
base.LogTo("Changes", "\twaiting for a revision...")
db.tapNotifier.L.Lock()
defer db.tapNotifier.L.Unlock()
db.tapNotifier.Wait()
base.LogTo("Changes", "\t...done waiting")
return true
}
// Given a newly changed document (received from the tap feed), adds change entries to channels.
// The JSON must be the raw document from the bucket, with the metadata and all.
func (c *changeCache) DocChanged(docID string, docJSON []byte) {
entryTime := time.Now()
// ** This method does not directly access any state of c, so it doesn't lock.
go func() {
// Is this a user/role doc?
if strings.HasPrefix(docID, auth.UserKeyPrefix) {
c.processPrincipalDoc(docID, docJSON, true)
return
} else if strings.HasPrefix(docID, auth.RoleKeyPrefix) {
c.processPrincipalDoc(docID, docJSON, false)
return
}
// First unmarshal the doc (just its metadata, to save time/memory):
doc, err := unmarshalDocumentSyncData(docJSON, false)
if err != nil || !doc.hasValidSyncData() {
base.Warn("changeCache: Error unmarshaling doc %q: %v", docID, err)
return
}
if doc.Sequence <= c.initialSequence {
return // Tap is sending us an old value from before I started up; ignore it
}
// Record a histogram of the Tap feed's lag:
tapLag := time.Since(doc.TimeSaved) - time.Since(entryTime)
lagMs := int(tapLag/(100*time.Millisecond)) * 100
changeCacheExpvars.Add(fmt.Sprintf("lag-tap-%04dms", lagMs), 1)
// If the doc update wasted any sequences due to conflicts, add empty entries for them:
for _, seq := range doc.UnusedSequences {
base.LogTo("Cache", "Received unused #%d for (%q / %q)", seq, docID, doc.CurrentRev)
change := &LogEntry{
Sequence: seq,
TimeReceived: time.Now(),
}
c.processEntry(change)
}
// Now add the entry for the new doc revision:
change := &LogEntry{
Sequence: doc.Sequence,
DocID: docID,
RevID: doc.CurrentRev,
Flags: doc.Flags,
TimeReceived: time.Now(),
TimeSaved: doc.TimeSaved,
Channels: doc.Channels,
}
base.LogTo("Cache", "Received #%d after %3dms (%q / %q)", change.Sequence, int(tapLag/time.Millisecond), change.DocID, change.RevID)
changedChannels := c.processEntry(change)
if c.onChange != nil && len(changedChannels) > 0 {
c.onChange(changedChannels)
}
}()
}
// Prepends an array of entries to this one, skipping ones that I already have.
// The new array needs to overlap with my current log, i.e. must contain the same sequence as
// c.logs[0], otherwise nothing will be added because the method can't confirm that there are no
// missing sequences in between.
// Returns the number of entries actually prepended.
func (c *channelCache) prependChanges(changes LogEntries, changesValidFrom uint64, openEnded bool) int {
c.lock.Lock()
defer c.lock.Unlock()
log := c.logs
if len(log) == 0 {
// If my cache is empty, just copy the new changes:
if len(changes) > 0 {
if !openEnded && changes[len(changes)-1].Sequence < c.validFrom {
return 0 // changes might not go all the way to the current time
}
if excess := len(changes) - ChannelCacheMaxLength; excess > 0 {
changes = changes[excess:]
changesValidFrom = changes[0].Sequence
}
c.logs = make(LogEntries, len(changes))
copy(c.logs, changes)
base.LogTo("Cache", " Initialized cache of %q with %d entries from view (#%d--#%d)",
c.channelName, len(changes), changes[0].Sequence, changes[len(changes)-1].Sequence)
}
c.validFrom = changesValidFrom
return len(changes)
} else if len(changes) == 0 {
if openEnded && changesValidFrom < c.validFrom {
c.validFrom = changesValidFrom
}
return 0
} else {
// Look for an overlap, and prepend everything up to that point:
firstSequence := log[0].Sequence
if changes[0].Sequence <= firstSequence {
for i := len(changes) - 1; i >= 0; i-- {
if changes[i].Sequence == firstSequence {
if excess := i + len(log) - ChannelCacheMaxLength; excess > 0 {
changes = changes[excess:]
changesValidFrom = changes[0].Sequence
i -= excess
}
if i > 0 {
newLog := make(LogEntries, 0, i+len(log))
newLog = append(newLog, changes[0:i]...)
newLog = append(newLog, log...)
c.logs = newLog
base.LogTo("Cache", " Added %d entries from view (#%d--#%d) to cache of %q",
i, changes[0].Sequence, changes[i-1].Sequence, c.channelName)
}
c.validFrom = changesValidFrom
return i
}
}
}
return 0
}
}
// Saves a channel log, _if_ there isn't already one in the database.
func (c *channelLogWriter) addChangeLog_(log *channels.ChangeLog) (added bool, err error) {
added, err = c.bucket.AddRaw(channelLogDocID(c.channelName), 0, encodeChannelLog(log))
if added {
base.LogTo("ChannelLog", "Added missing channel-log %q with %d entries",
c.channelName, log.Len())
} else {
base.LogTo("ChannelLog", "Didn't add channel-log %q with %d entries (err=%v)",
c.channelName, log.Len())
}
return
}
func (db *Database) getOldRevisionJSON(docid string, revid string) ([]byte, error) {
data, err := db.Bucket.GetRaw(oldRevisionKey(docid, revid))
if base.IsDocNotFoundError(err) {
base.LogTo("CRUD+", "No old revision %q / %q", docid, revid)
err = nil
}
if data != nil {
base.LogTo("CRUD+", "Got old revision %q / %q --> %d bytes", docid, revid, len(data))
}
return data, err
}
// Updates the Channels property of a document object with current & past channels.
// Returns the set of channels that have changed (document joined or left in this revision)
func (doc *document) updateChannels(newChannels base.Set) (changedChannels base.Set) {
var changed []string
oldChannels := doc.Channels
if oldChannels == nil {
oldChannels = ChannelMap{}
doc.Channels = oldChannels
} else {
// Mark every no-longer-current channel as unsubscribed:
curSequence := doc.Sequence
for channel, removal := range oldChannels {
if removal == nil && !newChannels.Contains(channel) {
oldChannels[channel] = &ChannelRemoval{
Seq: curSequence,
RevID: doc.CurrentRev,
Deleted: doc.Deleted}
changed = append(changed, channel)
}
}
}
// Mark every current channel as subscribed:
for channel, _ := range newChannels {
if value, exists := oldChannels[channel]; value != nil || !exists {
oldChannels[channel] = nil
changed = append(changed, channel)
}
}
if changed != nil {
base.LogTo("CRUD", "\tDoc %q in channels %q", doc.ID, newChannels)
changedChannels = channels.SetOf(changed...)
}
return
}
// Top-level handler call. It's passed a pointer to the specific method to run.
func (h *handler) invoke(method handlerMethod) error {
base.LogTo("HTTP", "%s %s", h.rq.Method, h.rq.URL)
h.setHeader("Server", VersionString)
// If there is a "db" path variable, look up the database context:
if dbname, ok := h.PathVars()["db"]; ok {
h.context = h.server.databases[dbname]
if h.context == nil {
return &base.HTTPError{http.StatusNotFound, "no such database"}
}
}
// Authenticate; admin handlers can ignore missing credentials
if err := h.checkAuth(); err != nil {
if !h.admin {
return err
}
}
// Now look up the database:
if h.context != nil {
var err error
h.db, err = db.GetDatabase(h.context.dbcontext, h.user)
if err != nil {
return err
}
}
return method(h) // Call the actual handler code
}
// Writes the response status code, and if it's an error writes a JSON description to the body.
func (h *handler) writeStatus(status int, message string) {
if status < 300 {
h.response.WriteHeader(status)
h.logStatus(status, message)
return
}
// Got an error:
var errorStr string
switch status {
case http.StatusNotFound:
errorStr = "not_found"
case http.StatusConflict:
errorStr = "conflict"
default:
errorStr = http.StatusText(status)
if errorStr == "" {
errorStr = fmt.Sprintf("%d", status)
}
}
h.setHeader("Content-Type", "application/json")
h.response.WriteHeader(status)
base.LogTo("HTTP", " --> %d %s", status, message)
jsonOut, _ := json.Marshal(db.Body{"error": errorStr, "reason": message})
h.response.Write(jsonOut)
}
func (h *handler) logStatus(status int, message string) {
if base.LogKeys["HTTP+"] {
duration := float64(time.Since(h.startTime)) / float64(time.Millisecond)
base.LogTo("HTTP+", "#%03d: --> %d %s (%.1f ms)",
h.serialNumber, status, message, duration)
}
}
// Updates the Access property of a document object
func (db *Database) updateDocAccess(doc *document, newAccess channels.AccessMap) (changed bool) {
for name, access := range doc.Access {
if access.UpdateAtSequence(newAccess[name], doc.Sequence) {
if len(access) == 0 {
delete(doc.Access, name)
}
changed = true
db.invalUserChannels(name)
}
}
for name, access := range newAccess {
if _, existed := doc.Access[name]; !existed {
changed = true
if doc.Access == nil {
doc.Access = UserAccessMap{}
}
doc.Access[name] = access.AtSequence(doc.Sequence)
db.invalUserChannels(name)
}
}
if changed {
base.LogTo("Access", "Doc %q grants access: %v", doc.ID, doc.Access)
}
return
}
func NewDatabaseContext(dbName string, bucket base.Bucket) (*DatabaseContext, error) {
context := &DatabaseContext{
Name: dbName,
Bucket: bucket,
tapNotifier: sync.NewCond(&sync.Mutex{}),
}
var err error
context.sequences, err = newSequenceAllocator(bucket)
if err != nil {
return nil, err
}
tapFeed, err := bucket.StartTapFeed(walrus.TapArguments{Backfill: walrus.TapNoBackfill})
if err != nil {
return nil, err
}
// Start a goroutine to broadcast to the tapNotifier whenever a document changes:
go func() {
for event := range tapFeed.Events() {
if event.Opcode == walrus.TapMutation || event.Opcode == walrus.TapDeletion {
key := string(event.Key)
if strings.HasPrefix(key, "_sync:") && !strings.HasPrefix(key, "_sync:user") &&
!strings.HasPrefix(key, "_sync:role") {
continue // ignore metadata docs (sequence counter, attachments, local docs...)
}
base.LogTo("Changes", "Notifying that %q changed (key=%q)", dbName, event.Key)
context.tapNotifier.Broadcast()
}
}
}()
return context, nil
}
func (c *changeCache) processPrincipalDoc(docID string, docJSON []byte, isUser bool) {
// Currently the cache isn't really doing much with user docs; mostly it needs to know about
// them because they have sequence numbers, so without them the sequence of sequences would
// have gaps in it, causing later sequences to get stuck in the queue.
princ, err := c.context.Authenticator().UnmarshalPrincipal(docJSON, "", 0, isUser)
if princ == nil {
base.Warn("changeCache: Error unmarshaling doc %q: %v", docID, err)
return
}
sequence := princ.Sequence()
if sequence <= c.initialSequence {
return // Tap is sending us an old value from before I started up; ignore it
}
// Now add the (somewhat fictitious) entry:
change := &LogEntry{
Sequence: sequence,
TimeReceived: time.Now(),
}
if isUser {
change.DocID = "_user/" + princ.Name()
} else {
change.DocID = "_role/" + princ.Name()
}
base.LogTo("Cache", "Received #%d (%q)", change.Sequence, change.DocID)
c.processEntry(change)
}
// HTTP handler for _dump
func (h *handler) handleDump() error {
viewName := h.PathVars()["view"]
base.LogTo("HTTP", "Dump view %q", viewName)
opts := db.Body{"stale": false, "reduce": false}
result, err := h.db.Bucket.View("sync_gateway", viewName, opts)
if err != nil {
return err
}
title := fmt.Sprintf("/%s: “%s” View", html.EscapeString(h.db.Name), html.EscapeString(viewName))
h.setHeader("Content-Type", `text/html; charset="UTF-8"`)
h.response.Write([]byte(fmt.Sprintf(
`<!DOCTYPE html><html><head><title>%s</title></head><body>
<h1>%s</h1><code>
<table border=1>
`,
title, title)))
h.response.Write([]byte("\t<tr><th>Key</th><th>Value</th><th>ID</th></tr>\n"))
for _, row := range result.Rows {
key, _ := json.Marshal(row.Key)
value, _ := json.Marshal(row.Value)
h.response.Write([]byte(fmt.Sprintf("\t<tr><td>%s</td><td>%s</td><td><em>%s</em></td>",
html.EscapeString(string(key)), html.EscapeString(string(value)), html.EscapeString(row.ID))))
h.response.Write([]byte("</tr>\n"))
}
h.response.Write([]byte("</table>\n</code></html></body>"))
return nil
}
func (db *Database) AddToChangeLogs(changedChannels base.Set, channelMap ChannelMap, entry channels.LogEntry, parentRevID string) error {
var err error
base.LogTo("Changes", "Updating #%d %q/%q in channels %s", entry.Sequence, entry.DocID, entry.RevID, changedChannels)
for channel, removal := range channelMap {
if removal != nil && removal.Seq != entry.Sequence {
continue
}
// Set Removed flag appropriately for this channel:
if removal != nil {
entry.Flags |= channels.Removed
} else {
entry.Flags = entry.Flags &^ channels.Removed
}
if err1 := db.AddToChangeLog(channel, entry, parentRevID); err != nil {
err = err1
}
}
// Finally, add to the universal "*" channel.
if EnableStarChannelLog {
entry.Flags = entry.Flags &^ channels.Removed
if err1 := db.AddToChangeLog("*", entry, parentRevID); err != nil {
err = err1
}
}
return err
}
// Updates a document's channel/role UserAccessMap with new access settings from an AccessMap.
// Returns an array of the user/role names whose access has changed as a result.
func (accessMap *UserAccessMap) updateAccess(doc *document, newAccess channels.AccessMap) (changedUsers []string) {
// Update users already appearing in doc.Access:
for name, access := range *accessMap {
if access.UpdateAtSequence(newAccess[name], doc.Sequence) {
if len(access) == 0 {
delete(*accessMap, name)
}
changedUsers = append(changedUsers, name)
}
}
// Add new users who are in newAccess but not accessMap:
for name, access := range newAccess {
if _, existed := (*accessMap)[name]; !existed {
if *accessMap == nil {
*accessMap = UserAccessMap{}
}
(*accessMap)[name] = channels.AtSequence(access, doc.Sequence)
changedUsers = append(changedUsers, name)
}
}
if changedUsers != nil {
what := "channel"
if accessMap == &doc.RoleAccess {
what = "role"
}
base.LogTo("Access", "Doc %q grants %s access: %v", doc.ID, what, *accessMap)
}
return changedUsers
}
// HTTP handler for _dumpchannel
func (h *handler) handleDumpChannel() error {
channelName := h.PathVar("channel")
since := h.getIntQuery("since", 0)
base.LogTo("HTTP", "Dump channel %q", channelName)
chanLog, err := h.db.GetChangeLog(channelName, since)
if err != nil {
return err
} else if chanLog == nil {
return base.HTTPErrorf(http.StatusNotFound, "no such channel")
}
title := fmt.Sprintf("/%s: “%s” Channel", html.EscapeString(h.db.Name), html.EscapeString(channelName))
h.setHeader("Content-Type", `text/html; charset="UTF-8"`)
h.response.Write([]byte(fmt.Sprintf(
`<!DOCTYPE html><html><head><title>%s</title></head><body>
<h1>%s</h1><code>
<p>Since = %d</p>
<table border=1>
`,
title, title, chanLog.Since)))
h.response.Write([]byte("\t<tr><th>Seq</th><th>Doc</th><th>Rev</th><th>Flags</th></tr>\n"))
for _, entry := range chanLog.Entries {
h.response.Write([]byte(fmt.Sprintf("\t<tr><td>%d</td><td>%s</td><td>%s</td><td>%08b</td>",
entry.Sequence,
html.EscapeString(entry.DocID), html.EscapeString(entry.RevID), entry.Flags)))
h.response.Write([]byte("</tr>\n"))
}
h.response.Write([]byte("</table>\n</code></html></body>"))
return nil
}
// Updates the Channels property of a document object with current & past channels
func (db *Database) updateDocChannels(doc *document, newChannels channels.Set) (changed bool) {
channels := doc.Channels
if channels == nil {
channels = ChannelMap{}
doc.Channels = channels
} else {
// Mark every previous channel as unsubscribed:
curSequence := doc.Sequence
for channel, seq := range channels {
if seq == nil {
channels[channel] = &ChannelRemoval{curSequence, doc.CurrentRev}
changed = true
}
}
}
// Mark every current channel as subscribed:
for channel, _ := range newChannels {
if value, exists := channels[channel]; value != nil || !exists {
channels[channel] = nil
changed = true
}
}
if changed {
base.LogTo("CRUD", "\tDoc %q in channels %q", doc.ID, newChannels)
}
return changed
}
// Moves a revision's ancestor's body out of the document object and into a separate db doc.
func (db *Database) backupAncestorRevs(doc *document, revid string) error {
// Find an ancestor that still has JSON in the document:
var json []byte
for {
if revid = doc.History.getParent(revid); revid == "" {
return nil // No ancestors with JSON found
} else if json = doc.getRevisionJSON(revid); json != nil {
break
}
}
// Store the JSON as a separate doc in the bucket:
if err := db.setOldRevisionJSON(doc.ID, revid, json); err != nil {
// This isn't fatal since we haven't lost any information; just warn about it.
base.Warn("backupAncestorRevs failed: doc=%q rev=%q err=%v", doc.ID, revid, err)
return err
}
// Nil out the rev's body in the document struct:
if revid == doc.CurrentRev {
doc.body = nil
} else {
doc.History.setRevisionBody(revid, nil)
}
base.LogTo("CRUD+", "Backed up obsolete rev %q/%q", doc.ID, revid)
return nil
}
// Gets an external document and applies it as a new revision to the managed document.
func (s *Shadower) pullDocument(key string, value []byte, isDeletion bool, cas uint64, flags uint32) error {
var body Body
if isDeletion {
body = Body{"_deleted": true}
} else {
if err := json.Unmarshal(value, &body); err != nil {
base.LogTo("Shadow", "Doc %q is not JSON; skipping", key)
return nil
}
}
db, _ := CreateDatabase(s.context)
_, err := db.updateDoc(key, false, func(doc *document) (Body, error) {
// (Be careful: this block can be invoked multiple times if there are races!)
if doc.UpstreamCAS != nil && *doc.UpstreamCAS == cas {
return nil, couchbase.UpdateCancel // we already have this doc revision
}
base.LogTo("Shadow+", "Pulling %q, CAS=%x ... have UpstreamRev=%q, UpstreamCAS=%x", key, cas, doc.UpstreamRev, doc.UpstreamCAS)
// Compare this body to the current revision body to see if it's an echo:
parentRev := doc.UpstreamRev
newRev := doc.CurrentRev
if !reflect.DeepEqual(body, doc.getRevision(newRev)) {
// Nope, it's not. Assign it a new rev ID
generation, _ := parseRevID(parentRev)
newRev = createRevID(generation+1, parentRev, body)
}
doc.UpstreamRev = newRev
doc.UpstreamCAS = &cas
body["_rev"] = newRev
if doc.History[newRev] == nil {
// It's a new rev, so add it to the history:
doc.History.addRevision(RevInfo{ID: newRev, Parent: parentRev, Deleted: isDeletion})
base.LogTo("Shadow", "Pulling %q, CAS=%x --> rev %q", key, cas, newRev)
} else {
// We already have this rev; but don't cancel, because we do need to update the
// doc's UpstreamRev/UpstreamCAS fields.
base.LogTo("Shadow+", "Not pulling %q, CAS=%x (echo of rev %q)", key, cas, newRev)
}
return body, nil
})
if err == couchbase.UpdateCancel {
err = nil
}
return err
}
func (listener *changeListener) notifyStopping() {
listener.tapNotifier.L.Lock()
listener.counter = 0
listener.keyCounts = map[string]uint64{}
base.LogTo("Changes+", "Notifying that changeListener is stopping")
listener.tapNotifier.Broadcast()
listener.tapNotifier.L.Unlock()
}
// Stores a base64-encoded attachment and returns the key to get it by.
func (db *Database) setAttachment(attachment []byte) (AttachmentKey, error) {
key := AttachmentKey(sha1DigestKey(attachment))
_, err := db.Bucket.AddRaw(attachmentKeyToString(key), 0, attachment)
if err == nil {
base.LogTo("Attach", "\tAdded attachment %q", key)
}
return key, err
}
// HTTP handler for GET _design/$ddoc/_view/$view
func (h *handler) handleView() error {
ddocName := h.PathVar("ddoc")
if ddocName == "" {
ddocName = "sync_gateway"
}
viewName := h.PathVar("view")
opts := db.Body{}
qStale := h.getQuery("stale")
if "" != qStale {
opts["stale"] = qStale == "true"
}
qReduce := h.getQuery("reduce")
if "" != qReduce {
opts["reduce"] = qReduce == "true"
}
qStartkey := h.getQuery("startkey")
if "" != qStartkey {
var sKey interface{}
errS := json.Unmarshal([]byte(qStartkey), &sKey)
if errS != nil {
return errS
}
opts["startkey"] = sKey
}
qEndkey := h.getQuery("endkey")
if "" != qEndkey {
var eKey interface{}
errE := json.Unmarshal([]byte(qEndkey), &eKey)
if errE != nil {
return errE
}
opts["endkey"] = eKey
}
qGroupLevel := h.getQuery("group_level")
if "" != qGroupLevel {
opts["group_level"] = int(h.getIntQuery("group_level", 1))
}
qGroup := h.getQuery("group")
if "" != qGroup {
opts["group"] = qGroup == "true"
}
qLimit := h.getQuery("limit")
if "" != qLimit {
opts["limit"] = int(h.getIntQuery("limit", 1))
}
base.LogTo("HTTP", "JSON view %q/%q - opts %v", ddocName, viewName, opts)
var result interface{}
err := h.db.QueryDesignDoc(ddocName, viewName, opts, &result)
if err != nil {
return err
}
h.setHeader("Content-Type", `application/json; charset="UTF-8"`)
h.writeJSON(result)
return nil
}
// Waits until the counter exceeds the given value. Returns the new counter.
func (listener *changeListener) Wait(counter uint64) uint64 {
listener.tapNotifier.L.Lock()
defer listener.tapNotifier.L.Unlock()
base.LogTo("Changes+", "Waiting for %q's count to pass %d",
listener.bucket.GetName(), listener.counter)
for listener.counter == counter {
listener.tapNotifier.Wait()
}
return listener.counter
}
// Invalidates the channel list of a user/role by saving its Channels() property as nil.
func (auth *Authenticator) InvalidateChannels(p Principal) error {
if p != nil && p.Channels() != nil {
base.LogTo("Access", "Invalidate access of %q", p.Name())
p.setChannels(nil)
if err := auth.Save(p); err != nil {
return err
}
}
return nil
}
// Invalidates the role list of a user by saving its Roles() property as nil.
func (auth *Authenticator) InvalidateRoles(user User) error {
if user != nil && user.Channels() != nil {
base.LogTo("Access", "Invalidate roles of %q", user.Name())
user.setRoleNames(nil)
if err := auth.Save(user); err != nil {
return err
}
}
return nil
}
// Creates a Go-channel of all the changes made on a channel.
// Does NOT handle the Wait option. Does NOT check authorization.
func (db *Database) changesFeed(channel string, options ChangesOptions) (<-chan *ChangeEntry, error) {
dbExpvars.Add("channelChangesFeeds", 1)
log, err := db.changeCache.GetChangesInChannel(channel, options)
if err != nil {
return nil, err
}
if len(log) == 0 {
// There are no entries newer than 'since'. Return an empty feed:
feed := make(chan *ChangeEntry)
close(feed)
return feed, nil
}
feed := make(chan *ChangeEntry, 1)
go func() {
defer close(feed)
// Now write each log entry to the 'feed' channel in turn:
for _, logEntry := range log {
if !options.Conflicts && (logEntry.Flags&channels.Hidden) != 0 {
//continue // FIX: had to comment this out.
// This entry is shadowed by a conflicting one. We would like to skip it.
// The problem is that if this is the newest revision of this doc, then the
// doc will appear under this sequence # in the changes view, which means
// we won't emit the doc at all because we already stopped emitting entries
// from the view before this point.
}
if logEntry.Sequence >= options.Since.TriggeredBy {
options.Since.TriggeredBy = 0
}
seqID := SequenceID{
Seq: logEntry.Sequence,
TriggeredBy: options.Since.TriggeredBy,
}
change := ChangeEntry{
Seq: seqID,
ID: logEntry.DocID,
Deleted: (logEntry.Flags & channels.Deleted) != 0,
Changes: []ChangeRev{{"rev": logEntry.RevID}},
branched: (logEntry.Flags & channels.Branched) != 0,
}
if logEntry.Flags&channels.Removed != 0 {
change.Removed = channels.SetOf(channel)
}
select {
case <-options.Terminator:
base.LogTo("Changes+", "Aborting changesFeed")
return
case feed <- &change:
}
}
}()
return feed, nil
}
