WAL Tail API returns only single object

[m4ttek]

The following code always returns single object, even if WAL TAIL API (https://docs.arangodb.com/3.12/develop/http-api/replication/write-ahead-log/#tail-recent-server-operations) returns multiple json objects:

    protected CompletableFuture<Response<OperationResponse[]>> fetchEventsFromCurrentTick(ArangoClientProvider sourceProvider, ProcessingState processingState) {
        Request<OperationResponse[]> tailRequest =
                Request.<OperationResponse[]>builder().path(WAL_TAIL_PATH.formatted(sourceProvider.arangoDBName()))
                        .method(Request.Method.GET)
                        .queryParam("syncerId", processorSettings.walSyncerId)
                        .queryParam("chunkSize", String.valueOf(processorSettings.chunkSize))
                        .queryParam("lastScanned", String.valueOf(processingState.getLastScannedTick()))
                        .queryParam("from", String.valueOf(processingState.getCurrentTick()))
                        .build();

        return sourceProvider.getClient().execute(tailRequest, OperationResponse[].class);
    }

As far as I investigated it, it's caused by Jackson behaviour which only allows for properly defined json objects. Unfortunately, json objects are not wrapped in array in Arango API.

I tried using RawJson type - it doesn't matter.

[rashtao]

Hi @m4ttek ,

the problem is caused by the fact that this API return response with content-type: x-arango-dump, which is:

The Content-Type of the result is application/x-arango-dump. This is an easy-to-process format, with all log events going onto separate lines in the response body. Each log event itself is a JSON object, …

But the serde only supports Json or Velocypack content types, therefore cannot handle these payloads.

To work around it, in #592 I have fixed the issue for deserialization targets RawBytes and RawJson.

[m4ttek]

@rashtao great, many thanks for quick response and fix. I'm looking forward to a new version of arango driver

[rashtao]

released in https://github.com/arangodb/arangodb-java-driver/releases/tag/v7.16.0

[m4ttek]

I've checked it and it's working now. Thanks