// 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)
}
refcounts, closer := st.getCollection(refcountsC)
defer closer()
var ops []txn.Op
for _, doc := range docs {
if doc.URL.Revision >= curl.Revision {
continue
}
key := charmGlobalKey(doc.URL)
refOp, err := nsRefcounts.RemoveOp(refcounts, key, 0)
if err != nil {
return nil, errors.Trace(err)
}
ops = append(ops, refOp, txn.Op{
C: charms.Name(),
Id: doc.DocID,
Assert: stillPlaceholder,
Remove: true,
})
}
return ops, 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
}
// 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
}
// 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
}
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
}
// 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
}