// readSkews reads all clock data for the client's namespace.
func (client *client) readSkews(collection mongo.Collection) (map[string]Skew, error) {
// Read the clock document, recording the time before and after completion.
readBefore := client.config.Clock.Now()
var clockDoc clockDoc
if err := collection.FindId(client.clockDocId()).One(&clockDoc); err != nil {
return nil, errors.Trace(err)
}
readAfter := client.config.Clock.Now()
if err := clockDoc.validate(); err != nil {
return nil, errors.Annotatef(err, "corrupt clock document")
}
// Create skew entries for each known writer...
skews, err := clockDoc.skews(readBefore, readAfter)
if err != nil {
return nil, errors.Trace(err)
}
// If a writer was previously known to us, and has not written since last
// time we read, we should keep the original skew, which is more accurate.
for writer, skew := range client.skews {
if skews[writer].LastWrite == skew.LastWrite {
skews[writer] = skew
}
}
// ...and overwrite our own with a zero skew, which will DTRT (assuming
// nobody's reusing client ids across machines with different clocks,
// which *should* never happen).
skews[client.config.Id] = Skew{}
return skews, nil
}
// exists returns whether the identified refcount doc exists.
func (nsRefcounts_) exists(coll mongo.Collection, key string) (bool, error) {
count, err := coll.FindId(key).Count()
if err != nil {
return false, errors.Trace(err)
}
return count != 0, nil
}
// deleteOldPlaceholderCharmsOps returns the txn ops required to delete all placeholder charm
// records older than the specified charm URL.
func deleteOldPlaceholderCharmsOps(st *State, charms mongo.Collection, curl *charm.URL) ([]txn.Op, error) {
// Get a regex with the charm URL and no revision.
noRevURL := curl.WithRevision(-1)
curlRegex := "^" + regexp.QuoteMeta(st.docID(noRevURL.String()))
var docs []charmDoc
query := bson.D{{"_id", bson.D{{"$regex", curlRegex}}}, {"placeholder", true}}
err := charms.Find(query).Select(bson.D{{"_id", 1}, {"url", 1}}).All(&docs)
if err != nil {
return nil, errors.Trace(err)
}
var ops []txn.Op
for _, doc := range docs {
if doc.URL.Revision >= curl.Revision {
continue
}
ops = append(ops, txn.Op{
C: charmsC,
Id: doc.DocID,
Assert: stillPlaceholder,
Remove: true,
})
}
return ops, nil
}
// StrictIncRefOp returns a txn.Op that increments the value of a
// refcount doc, or returns an error if it does not exist.
func (ns nsRefcounts_) StrictIncRefOp(coll mongo.Collection, key string, n int) (txn.Op, error) {
if exists, err := ns.exists(coll, key); err != nil {
return txn.Op{}, errors.Trace(err)
} else if !exists {
return txn.Op{}, errors.New("does not exist")
}
return ns.JustIncRefOp(coll.Name(), key, n), nil
}
// getEntitiesWithStatuses returns the ids for all entities that
// have history entries
func getEntitiesWithStatuses(coll mongo.Collection) ([]string, error) {
var globalKeys []string
err := coll.Find(nil).Distinct("globalkey", &globalKeys)
if err != nil {
return nil, errors.Trace(err)
}
return globalKeys, nil
}
// getEntitiesWithStatuses returns the ids for all entities that
// have history entries
func getEntitiesWithStatuses(coll mongo.Collection) ([]string, error) {
var entityKeys []string
err := coll.Find(nil).Distinct("entityid", &entityKeys)
if err != nil {
return nil, errors.Trace(err)
}
return entityKeys, nil
}
// AliveDecRefOp returns a txn.Op that decrements the value of a
// refcount doc, or an error if the doc does not exist or the count
// would go below 0.
func (ns nsRefcounts_) AliveDecRefOp(coll mongo.Collection, key string) (txn.Op, error) {
if refcount, err := ns.read(coll, key); err != nil {
return txn.Op{}, errors.Trace(err)
} else if refcount < 1 {
return txn.Op{}, errors.New("cannot decRef below 0")
}
return ns.justDecRefOp(coll.Name(), key, 0), nil
}
// StrictCreateOp returns a txn.Op that creates a refcount document as
// configured, or an error if the document already exists.
func (ns nsRefcounts_) StrictCreateOp(coll mongo.Collection, key string, value int) (txn.Op, error) {
if exists, err := ns.exists(coll, key); err != nil {
return txn.Op{}, errors.Trace(err)
} else if exists {
return txn.Op{}, errors.New("refcount already exists")
}
return ns.JustCreateOp(coll.Name(), key, value), nil
}
// LazyCreateOp returns a txn.Op that creates a refcount document; or
// false if the document already exists.
func (ns nsRefcounts_) LazyCreateOp(coll mongo.Collection, key string) (txn.Op, bool, error) {
if exists, err := ns.exists(coll, key); err != nil {
return txn.Op{}, false, errors.Trace(err)
} else if exists {
return txn.Op{}, false, nil
}
return ns.JustCreateOp(coll.Name(), key, 0), true, nil
}
// read returns the value stored in the identified refcount doc.
func (nsRefcounts_) read(coll mongo.Collection, key string) (int, error) {
var doc refcountDoc
if err := coll.FindId(key).One(&doc); err == mgo.ErrNotFound {
return 0, errors.NotFoundf("refcount %q", key)
} else if err != nil {
return 0, errors.Trace(err)
}
return doc.RefCount, nil
}
func newStateCollection(collection mongo.Collection, envUUID string) mongo.Collection {
if multiEnvCollections.Contains(collection.Name()) {
return &envStateCollection{
WriteCollection: collection.Writeable(),
envUUID: envUUID,
}
}
return collection
}
// RemoveOp returns a txn.Op that removes a refcount doc so long as its
// refcount is the supplied value, or an error.
func (ns nsRefcounts_) RemoveOp(coll mongo.Collection, key string, value int) (txn.Op, error) {
refcount, err := ns.read(coll, key)
if err != nil {
return txn.Op{}, errors.Trace(err)
}
if refcount != value {
return txn.Op{}, errRefcountChanged
}
return ns.JustRemoveOp(coll.Name(), key, value), nil
}
// getOldestTimeToKeep returns the create time for the oldest
// status log to be kept.
func getOldestTimeToKeep(coll mongo.Collection, globalKey string, size int) (int64, bool, error) {
result := historicalStatusDoc{}
err := coll.Find(bson.D{{"globalkey", globalKey}}).Sort("-updated").Skip(size - 1).One(&result)
if err == mgo.ErrNotFound {
return -1, false, nil
}
if err != nil {
return -1, false, errors.Trace(err)
}
return result.Updated, true, nil
}
// DyingDecRefOp returns a txn.Op that decrements the value of a
// refcount doc and deletes it if the count reaches 0; if the Op will
// cause a delete, the bool result will be true. It will return an error
// if the doc does not exist or the count would go below 0.
func (ns nsRefcounts_) DyingDecRefOp(coll mongo.Collection, key string) (txn.Op, bool, error) {
refcount, err := ns.read(coll, key)
if err != nil {
return txn.Op{}, false, errors.Trace(err)
}
if refcount < 1 {
return txn.Op{}, false, errors.New("cannot decRef below 0")
} else if refcount > 1 {
return ns.justDecRefOp(coll.Name(), key, 1), false, nil
}
return ns.JustRemoveOp(coll.Name(), key, 1), true, nil
}
// setStatusOp returns a txn.Op that updates the status of the
// identified payload. If the payload doesn't exist, it returns
// errAlreadyRemoved.
func (nsPayloads_) setStatusOp(payloads mongo.Collection, docID string, status string) (txn.Op, error) {
count, err := payloads.FindId(docID).Count()
if err != nil {
return txn.Op{}, errors.Trace(err)
} else if count == 0 {
return txn.Op{}, errAlreadyRemoved
}
return txn.Op{
C: payloads.Name(),
Id: docID,
Assert: txn.DocExists,
Update: bson.D{{"$set", bson.D{{"state", status}}}},
}, nil
}
// untrackOp returns a txn.Op that will unconditionally remove the
// identified document. If the payload doesn't exist, it returns
// errAlreadyRemoved.
func (nsPayloads_) untrackOp(payloads mongo.Collection, docID string) (txn.Op, error) {
count, err := payloads.FindId(docID).Count()
if err != nil {
return txn.Op{}, errors.Trace(err)
} else if count == 0 {
return txn.Op{}, errAlreadyRemoved
}
return txn.Op{
C: payloads.Name(),
Id: docID,
Assert: txn.DocExists,
Remove: true,
}, nil
}
// CurrentOp returns the current reference count value, and a txn.Op that
// asserts that the refcount has that value, or an error. If the refcount
// doc does not exist, then the op will assert that the document does not
// exist instead, and no error is returned.
func (ns nsRefcounts_) CurrentOp(coll mongo.Collection, key string) (txn.Op, int, error) {
refcount, err := ns.read(coll, key)
if errors.IsNotFound(err) {
return txn.Op{
C: coll.Name(),
Id: key,
Assert: txn.DocMissing,
}, 0, nil
}
if err != nil {
return txn.Op{}, -1, errors.Trace(err)
}
return txn.Op{
C: coll.Name(),
Id: key,
Assert: bson.D{{"refcount", refcount}},
}, refcount, nil
}
// trackOp returns a txn.Op that will either insert or update the
// supplied payload, and fail if the observed precondition changes.
func (nsPayloads_) trackOp(payloads mongo.Collection, doc payloadDoc) (txn.Op, error) {
docID := nsPayloads.docID(doc.UnitID, doc.Name)
payloadOp := txn.Op{
C: payloads.Name(),
Id: docID,
}
count, err := payloads.FindId(docID).Count()
if err != nil {
return txn.Op{}, errors.Trace(err)
} else if count == 0 {
payloadOp.Assert = txn.DocMissing
payloadOp.Insert = doc
} else {
payloadOp.Assert = txn.DocExists
payloadOp.Update = bson.D{{"$set", doc}}
}
return payloadOp, nil
}
// readEntries reads all lease data for the client's namespace.
func (client *client) readEntries(collection mongo.Collection) (map[string]entry, error) {
// Read all lease documents in the client's namespace.
query := bson.M{
fieldType: typeLease,
fieldNamespace: client.config.Namespace,
}
iter := collection.Find(query).Iter()
// Extract valid entries for each one.
entries := make(map[string]entry)
var leaseDoc leaseDoc
for iter.Next(&leaseDoc) {
name, entry, err := leaseDoc.entry()
if err != nil {
return nil, errors.Annotatef(err, "corrupt lease document %q", leaseDoc.Id)
}
entries[name] = entry
}
if err := iter.Close(); err != nil {
return nil, errors.Trace(err)
}
return entries, nil
}
func newBinaryStorage(uuid string, metadataCollection mongo.Collection, txnRunner jujutxn.Runner) binarystorage.Storage {
db := metadataCollection.Writeable().Underlying().Database
rs := blobstore.NewGridFS(blobstoreDB, blobstoreDB, db.Session)
managedStorage := blobstore.NewManagedStorage(db, rs)
return binarystorageNew(uuid, managedStorage, metadataCollection, txnRunner)
}
func isAliveWithSession(coll mongo.Collection, id interface{}) (bool, error) {
n, err := coll.Find(bson.D{{"_id", id}, {"life", Alive}}).Count()
return n == 1, err
}
func isNotDeadWithSession(coll mongo.Collection, id interface{}) (bool, error) {
n, err := coll.Find(bson.D{{"_id", id}, {"life", bson.D{{"$ne", Dead}}}}).Count()
return n == 1, err
}