giant-squid


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An alternative MWA ASVO client. See the MWA ASVO page for more info.

giant-squid was originally created as a library to do MWA ASVO related tasks in the Haskell programming language (now available in Rust). However, it's not just a library; the giant-squid executable acts as an alternative to the manta-ray-client and may better suit users for a few reasons:

1) By default, giant-squid stream unzips the downloads from ASVO. In other words, rather than downloading a potentially large (> 100 GiB!) zip file and then unzipping it yourself (thereby occupying double the space of the original zip and performing a very expensive IO operation), it is possible to get the files without performing an unzip.

2) giant-squid does not require a CSV file to submit jobs; this is instead handled by command line arguments.

3) For any commands that accept obsids or job IDs, it is possible use text files instead. These files are unpacked as if you had typed them out manually, and each entry of the text file(s) are checked for validity (all ints and all 10-digits long); any exceptions are reported and the command fails.

4) One can ask giant-squid to print their ASVO queue as JSON; this makes parsing the state of your jobs in another programming language much simpler.

Usage

Print help text

bash giant-squid -h

This also applies to all of the subcommands, e.g. bash giant-squid download -h

Print the giant-squid version

bash giant-squid --version giant-squid -V (Useful if things are changing over time!)

List ASVO jobs

bash giant-squid list giant-squid l

List ASVO jobs in JSON

```bash

Any of the following work.

giant-squid list --json giant-squid list -j giant-squid l -j ```

Example output: bash giant-squid list -j {"325430":{"obsid":1090528304,"jobId":325430,"jobType":"DownloadVisibilities","jobState":"Ready","files":[{"fileName":"1090528304_vis.zip","fileSize":10762878689,"fileHash":"ca0e89e56cbeb05816dad853f5bab0b4075097da"}]},"325431":{"obsid":1090528432,"jobId":325431,"jobType":"DownloadVisibilities","jobState":"Ready","files":[{"fileName":"1090528432_vis.zip","fileSize":10762875021,"fileHash":"9d9c3c0f56a2bb4e851aa63cdfb79095b29c66c9"}]}}

jobType is allowed to be any of: - Conversion - DownloadVisibilities - DownloadMetadata - DownloadVoltage - CancelJob

jobState is allowed to be any of: - Queued - Processing - Ready - Error: Text (e.g. "Error: some error message") - Expired - Cancelled

Example reading this in Python: ```bash $ giant-squid list -j > /tmp/asvo.json $ ipython Python 3.8.0 (default, Oct 23 2019, 18:51:26) Type 'copyright', 'credits' or 'license' for more information IPython 7.10.1 -- An enhanced Interactive Python. Type '?' for help.

In [1]: import json

In [2]: with open("/tmp/asvo.json", "r") as h: ...: q = json.load(h) ...:

In [3]: q.keys() Out[3]: dict_keys(['216087', '216241', '217628']) ```

Download ASVO jobs

To download job ID 12345: ```bash giant-squid download 12345

or

giant-squid d 12345 ```

To download obsid 1065880128: ```bash giant-squid download 1065880128

or

giant-squid d 1065880128 ```

(giant-squid differentiates between job IDs and obsids by the length of the number specified; 10-digit numbers are treated as obsids. If the ASVO ever serves up more than a billion jobs, you have permission to be upset with me. The same applies if this code is still being used in the year 2296.)

Text files containing job IDs or obsids may be used too.

By default, giant-squid will perform stream unzipping. Disable this with -k (or --keep-zip).

The MWA ASVO provides a SHA-1 of its downloads. To verify the integrity of your download, give a --hash to the download command. The additional computation by this action appears to be negligible, but I made this option non-default as it shouldn't be a problem anyway.

Submit ASVO jobs

Visibility downloads

A "visibility download job" refers to a job which provides a zip containing gpubox files, a metafits file and cotter flags for a single obsid.

To submit a visibility download job for the obsid 1065880128: ```bash giant-squid submit-vis 1065880128

or

giant-squid sv 1065880128 ```

Text files containing obsids may be used too.

If you want to check that your command works without actually submitting the obsids, then you can use the --dry-run option (short version -n).

It's possible to have ASVO jobs expire sooner than the default 7 days; useful when you are processing many jobs, as there is a limit to how many can be associated with your account! Use the --expire-days option (short version -e).

Conversion downloads

To submit a conversion job for obsid 1065880128: ```bash giant-squid submit-conv 1065880128

or

giant-squid sc 1065880128 ```

Text files containing obsids may be used too.

The default conversion options can be found by running the help text: bash giant-squid submit-conv -h

To change the default conversion options and/or specify more options, specify comma-separated key-value pairs like so: bash giant-squid submit-conv 1065880128 -p timeres=0.5,freqres=10

If you want to check that your command works without actually submitting the obsids, then you can use the --dry-run option (short version -n). More messages (including what giant-squid uses for the conversion options) can be accessed with -v (or --verbose). e.g. bash $ giant-squid submit-conv 1065880128 -nv -p timeres=0.5,freqres=10 20:40:24 [INFO] Would have submitted 1 obsids for conversion, using these parameters: {"allowmissing": "true", "conversion": "ms", "download_type": "conversion", "edgewidth": "160", "flagdcchannels": "true", "freqres": "10", "timeres": "0.5"}

It's possible to have ASVO jobs expire sooner than the default 7 days; useful when you are processing many jobs, as there is a limit to how many can be associated with your account! Use the --expire-days option (short version -e).

Metadata downloads

A "metadata download job" refers to a job which provides a zip containing a metafits file and cotter flags for a single obsid.

To submit a visibility download job for the obsid 1065880128: ```bash giant-squid submit-meta 1065880128

or

giant-squid sm 1065880128 ```

Text files containing obsids may be used too.

If you want to check that your command works without actually submitting the obsids, then you can use the --dry-run option (short version -n).

It's possible to have ASVO jobs expire sooner than the default 7 days; useful when you are processing many jobs, as there is a limit to how many can be associated with your account! Use the --expire-days option (short version -e).

Download performance

By default, when downloading, giant-squid will store 100 MiB of the download in memory before writing to disk. This is friendlier on disks (especially those belonging to supercomputers!), and can make downloads faster.

The amount of data to cache before writing can be tuned by setting GIANT_SQUID_BUF_SIZE. e.g.

bash export GIANT_SQUID_BUF_SIZE=50 giant-squid download 12345

would use 50 MiB of memory to cache the download before writing.

Installation

Pre-compiled

Have a look at the GitHub releases page.

Building from crates.io

Building from source

Other

The Haskell code is still available on chj's GitLab. Switching to Rust means that the code is more efficient and the code is easier to read (sorry Haskell. I love you, but you're weird).