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[ADDED] SecureDeleteMsg method to JetStreamManager #1025

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merged 1 commit into from Aug 4, 2022
Merged

[ADDED] SecureDeleteMsg method to JetStreamManager #1025

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37 changes: 30 additions & 7 deletions jsm.go
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Expand Up @@ -58,9 +58,13 @@ type JetStreamManager interface {
// The stream must have been created/updated with the AllowDirect boolean.
GetLastMsg(name, subject string, opts ...JSOpt) (*RawStreamMsg, error)

// DeleteMsg erases a message from a stream.
// DeleteMsg deletes a message from a stream. The message is marked as erased, but its value is not overwritten.
DeleteMsg(name string, seq uint64, opts ...JSOpt) error

// SecureDeleteMsg deletes a message from a stream. The deleted message is overwritten with random data
// As a result, this operation is slower than DeleteMsg()
SecureDeleteMsg(name string, seq uint64, opts ...JSOpt) error
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Wonder if we should not add an option instead of a new API, as we did for the direct get. For instance, we could have a JSOpt that is called nats.EraseMsg() or nats.SecureDelete() that would set a boolean in *jsOpts (see DirectGet() option).

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I thought about that, but I feel that in this case (having really only 2 options), 2 separate methods are a bit more straightforward to the user. JSOpt is already confusingly large bag of options and finding the one particular option which is applicable for a specific method is a hard job, even with good documentation.

Providing 2 methods on the other hand, should eliminate any confusion. If a user wants to delete message, they will stumble on 2 methods with relevant names: DeleteMsg(), which looks like a good starting point and SecureDeleteMsg(). Both have clear documentation and are not configurable (which is a good thing IMO).

WDYT?

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I started with adding a new API for the "direct get" but was told that it was better to add options instead. I do agree - however - that the JSOpt can be a bit confusing.
To sump up, I don't have objections per-se to add a new API (actually, in the C client I have js_DeleteMsg() and js_EraseMsg() APIs), just felt that the will was to go with options instead of new APIs. If other reviewers in the list are OK with new API, I am ok too.

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Usually I would lean into having an option in this case but after reading the ADR discussion, I reached the same conclusion in that in this case a new SecureDeleteMsg is what would fit better. TL;DR; of the ADR discussion, secure delete might have been a good default but considering the performance impact and the context of security, I think it sounds good to have its own function in this case.


// AddConsumer adds a consumer to a stream.
AddConsumer(stream string, cfg *ConsumerConfig, opts ...JSOpt) (*ConsumerInfo, error)

Expand Down Expand Up @@ -1012,7 +1016,8 @@ func convertDirectGetMsgResponseToMsg(name string, r *Msg) (*RawStreamMsg, error
}

type msgDeleteRequest struct {
Seq uint64 `json:"seq"`
Seq uint64 `json:"seq"`
NoErase bool `json:"no_erase,omitempty"`
}

// msgDeleteResponse is the response for a Stream delete request.
Expand All @@ -1022,6 +1027,7 @@ type msgDeleteResponse struct {
}

// DeleteMsg deletes a message from a stream.
// The message is marked as erased, but not overwritten
func (js *js) DeleteMsg(name string, seq uint64, opts ...JSOpt) error {
o, cancel, err := getJSContextOpts(js.opts, opts...)
if err != nil {
Expand All @@ -1031,17 +1037,34 @@ func (js *js) DeleteMsg(name string, seq uint64, opts ...JSOpt) error {
defer cancel()
}

if name == _EMPTY_ {
return ErrStreamNameRequired
return js.deleteMsg(o.ctx, name, &msgDeleteRequest{Seq: seq, NoErase: true})
}

// SecureDeleteMsg deletes a message from a stream. The deleted message is overwritten with random data
// As a result, this operation is slower than DeleteMsg()
func (js *js) SecureDeleteMsg(name string, seq uint64, opts ...JSOpt) error {
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If we go the option route, the implementation will simply have to set NoErase to opts.noErase (or whatever boolean you chose).

o, cancel, err := getJSContextOpts(js.opts, opts...)
if err != nil {
return err
}
if cancel != nil {
defer cancel()
}

req, err := json.Marshal(&msgDeleteRequest{Seq: seq})
return js.deleteMsg(o.ctx, name, &msgDeleteRequest{Seq: seq})
}

func (js *js) deleteMsg(ctx context.Context, stream string, req *msgDeleteRequest) error {
if err := checkStreamName(stream); err != nil {
return err
}
reqJSON, err := json.Marshal(req)
if err != nil {
return err
}

dsSubj := js.apiSubj(fmt.Sprintf(apiMsgDeleteT, name))
r, err := js.apiRequestWithContext(o.ctx, dsSubj, req)
dsSubj := js.apiSubj(fmt.Sprintf(apiMsgDeleteT, stream))
r, err := js.apiRequestWithContext(ctx, dsSubj, reqJSON)
if err != nil {
return err
}
Expand Down
131 changes: 131 additions & 0 deletions test/js_test.go
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Expand Up @@ -2207,10 +2207,141 @@ func TestJetStreamManagement_DeleteMsg(t *testing.T) {
}
originalSeq := meta.Sequence.Stream

// create a subscription on delete message API subject to verify the content of delete operation
apiSub, err := nc.SubscribeSync("$JS.API.STREAM.MSG.DELETE.foo")
if err != nil {
t.Fatalf("Error on subscribe: %v", err)
}
err = js.DeleteMsg("foo", originalSeq)
if err != nil {
t.Fatal(err)
}
msg, err = apiSub.NextMsg(1 * time.Second)
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
if str := string(msg.Data); !strings.Contains(str, "no_erase\":true") {
t.Fatalf("Request should not have no_erase field set: %s", str)
}

si, err = js.StreamInfo("foo")
if err != nil {
t.Fatal(err)
}
total = 14
if si.State.Msgs != total {
t.Errorf("Expected %d msgs, got: %d", total, si.State.Msgs)
}

// There should be only 4 messages since one deleted.
expected = 4
msgs = make([]*nats.Msg, 0)
ctx, cancel = context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()

sub, err = js.Subscribe("foo.C", func(msg *nats.Msg) {
msgs = append(msgs, msg)

if len(msgs) == expected {
cancel()
}
})
if err != nil {
t.Fatal(err)
}
<-ctx.Done()
sub.Unsubscribe()

msg = msgs[0]
meta, err = msg.Metadata()
if err != nil {
t.Fatal(err)
}
newSeq := meta.Sequence.Stream

// First message removed
if newSeq <= originalSeq {
t.Errorf("Expected %d to be higher sequence than %d", newSeq, originalSeq)
}
}

func TestJetStreamManagement_SecureDeleteMsg(t *testing.T) {
s := RunBasicJetStreamServer()
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Since really we don't know - from the client perspective - the difference between a delete and secure delete, what I would do is simply make sure that the client's "delete message request" contains the noErase boolean when it is a simple delete and not (or set to false) when using the secure version. This is done by creating a NATS subscription on the delete API subject and inspecting the content (see TestJetStreamConsumerConfigReplicasAndMemStorage for example)

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Good idea, I'll add that.

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I would have personally JUST done the check of the API request containing the no_erase (or not), the rest is testing server behavior really, but that's ok since code is already done.

defer shutdownJSServerAndRemoveStorage(t, s)

nc, js := jsClient(t, s)
defer nc.Close()

var err error

_, err = js.AddStream(&nats.StreamConfig{
Name: "foo",
Subjects: []string{"foo.A", "foo.B", "foo.C"},
})
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}

for i := 0; i < 5; i++ {
js.Publish("foo.A", []byte("A"))
js.Publish("foo.B", []byte("B"))
js.Publish("foo.C", []byte("C"))
}

si, err := js.StreamInfo("foo")
if err != nil {
t.Fatal(err)
}
var total uint64 = 15
if si.State.Msgs != total {
t.Errorf("Expected %d msgs, got: %d", total, si.State.Msgs)
}

expected := 5
msgs := make([]*nats.Msg, 0)
ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
defer cancel()

sub, err := js.Subscribe("foo.C", func(msg *nats.Msg) {
msgs = append(msgs, msg)
if len(msgs) == expected {
cancel()
}
})
if err != nil {
t.Fatal(err)
}
<-ctx.Done()
sub.Unsubscribe()

got := len(msgs)
if got != expected {
t.Fatalf("Expected %d, got %d", expected, got)
}

msg := msgs[0]
meta, err := msg.Metadata()
if err != nil {
t.Fatal(err)
}
originalSeq := meta.Sequence.Stream

// create a subscription on delete message API subject to verify the content of delete operation
apiSub, err := nc.SubscribeSync("$JS.API.STREAM.MSG.DELETE.foo")
if err != nil {
t.Fatalf("Error on subscribe: %v", err)
}
err = js.SecureDeleteMsg("foo", originalSeq)
if err != nil {
t.Fatal(err)
}
msg, err = apiSub.NextMsg(1 * time.Second)
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
if str := string(msg.Data); strings.Contains(str, "no_erase\":true") {
t.Fatalf("Request should not have no_erase field set: %s", str)
}

si, err = js.StreamInfo("foo")
if err != nil {
Expand Down