support aspera download

[atongsa]

Description of feature

aspera from ena link may be faster than ftp

[Midnighter]

Hi @atongsa,

I haven't yet come across Aspera in a Docker image which is a hard requirement for nf-core pipelines. If you come across a solution for that it would be possible to integrate it. Do you have some benchmarks comparing the speed, though, or is that just an idea that using Aspera would be faster? I think Aspera is also not officially supported by NCBI any longer, although it still works, of course.

[atongsa]

sorry, just idea, i dont test.

[asuragan]

Aspera is not officially supported by NCBI because prefetch and fasterq-dump additionally download the index files needed to decompress the .sra into .fastq. These index files are saved in {sra-toolkit folder}/refseq. Whereas using the NCBI API we only get a link to an .sra file, which we then have to decompress via fasterq-dump anyway. There is no difference in speed, because using ascp, curl, wget, etc we download .sra from AWS, but prefetch also downloads *.sra files from AWS. https://github.com/ncbi/sra-tools/wiki/Avoid-using-ascp-directly-for-downloads

But when we download the *.fastq.gz from ENA, the download speed via FTP is very limited, but aspera gives a much higher speed. For example, I was looking at the execution_report of a test run on AWS: https://nf-co.re/fetchngs/results#fetchngs/results-2d593fb504caf65301c78b8076272f895e364cd7/pipeline_info/execution_report_2021-09-15_16-37-52.html The NFCORE_FETCHNGS:FETCHNGS:SRA_FASTQ_FTP process took 5m 39s to download 46 MB via FTP, which means that the FTP download speed on the AWS server was about 150 KB/s. And about aspera in docker, aspera has its own image in docker hub: https://hub.docker.com/r/ibmcom/aspera-cli/

[Midnighter]

Sounds promising.

[Midnighter]

Hmm, would either of you be interested in contributing this feature? I'm afraid I won't have time to work on this myself.

[davetang]

I'm interested in contributing but will need some guidance. The Docker Hub link above for Aspera no longer exists, so I wrote my own Dockerfile and pushed it to Docker Hub.

You can use it by providing the download link and where to output the file.

docker run --rm -u $(id -u):$(id -g) -v $(pwd):$(pwd) -w $(pwd) davetang/aspera_connect:4.2.6.393 era-fasp@fasp.sra.ebi.ac.uk:vol1/fastq/SRR390/SRR390728/SRR390728_1.fastq.gz .

Using Aspera Connect is substantially faster than any other method on my home Internet connection. For example:

SRR292241_1.fastq.gz 100%  369MB  238Mb/s    00:13
Completed: 378151K bytes transferred in 13 seconds
 (227709K bits/sec), in 1 file.
SRR292241_2.fastq.gz 100%  376MB  272Mb/s    00:13
Completed: 385855K bytes transferred in 14 seconds
 (218815K bits/sec), in 1 file.
SRR390728_1.fastq.gz 100%   96MB  265Mb/s    00:05
Completed: 99006K bytes transferred in 5 seconds
 (141136K bits/sec), in 1 file.
SRR390728_2.fastq.gz 100%   97MB  261Mb/s    00:07
Completed: 99628K bytes transferred in 7 seconds
 (105342K bits/sec), in 1 file.

There's a tool called ffq, which you may already be aware of, that can be used to generate download links. I made a request for ffq to support Aspera Connect but it was ignored. I wrote a script (that needs a bit more work) to generate Aspera Connect download links from ffq.

Anyway, please let me know how I can contribute! I've just recently been learning about Nextflow and just joined the nf-core Slack workspace.

[Midnighter]

Hi @davetang,

Thank you for speaking up. That seems really cool.

For aspera, I wonder if will be possible to create a bioconda recipe for it? That will ensure a conda package and that BioContainers will be built which can then support Docker and Singularity.

We are aware of ffq, but I also wasn't 100% happy with it so far. I made a prototype of reworking it so that it is much faster, and can output the S3 links https://github.com/Midnighter/ffqf. So maybe I should work on spitting out aspera links, too, and finish up this tool?

Anyway, I think creating a bioconda recipe would be a good starting point, if the license of aspera allows this.

[davetang]

I have never built a Conda package before but I've always wanted to find out how.

I just found https://anaconda.org/hcc/aspera-cli and will check it out first.