arclink_fetch is a more sophisticated client that can be used to get data with a single command. It performs routing automatically, and can conveniently handle encryption. When you install SeisComp3 it is automatically installed on your computer together with SeisComp3, but it may also be installed as a standalone package for users wishing only to request data from an ArcLink server.
Please use these instructions carefully, and you use them at your own risk.
Command line options
- Show program’s version number and exit
- -h, --help
- Show this help message and exit
- -l, --longhelp
- Show a long help message describing the input file format for the requests and about the password file (-w option). Also presents a short description of the ArcLink protocol.
- Increase verbosity level
- Decrease verbosity level
- -a ADDRESS, --address=ADDRESS
- Address of primary ArcLink node (default webdc.eu:18001)
- -f REQUEST_FORMAT, --request-format=REQUEST_FORMAT
- Request format: breqfast, native (default native)
- -k DATA_FORMAT, --data-format=DATA_FORMAT
- Data format: mseed, mseed4k, fseed, dseed, inv[entory] (default mseed)
- -o OUTPUT_FILE, --output-file=OUTPUT_FILE
- Local file where downloaded data is to be written to
- -u USER, --user=USER
- User’s e-mail address
- -n, --no-resp-dict
- Avoid using response dictionary (default False)
- -g, --rebuild-volume
- Rebuild SEED volume (default False)
- -p, --proxy
- Proxy mode, no routing (default False)
- -t TIMEOUT, --timeout=TIMEOUT
- Timeout in seconds (default 300)
- -x RETRIES, --retries=RETRIES
- Download retries (default 5)
- -w SSLPASSWORDFILE, --password-file=SSLPASSWORDFILEUSER
- The file containing passwords used for decryption of encrypted data (default dcidpasswords.txt).
The mseed4k data format (-k mseed4k) enables a client side re-blocking of the received MiniSeed records from the server to a default block size of 4096. This is especially important when you are downloading data from two different networks that were archived with different block sizes and would like to receive a uniform (in terms of block size) MiniSeed file.
Some programs have problems to proper display miniseed packages with different block sizes on the same file. This issue can be avoided by instead of requesting MiniSeed data directly (-k mseed), just request re-blocked MiniSeed (-k mseed4k).
Rebuilding SEED volume
If -g option is used in combination with fseed data format (-k fseed), then instead of full SEED, inventory and Mini-SEED is requested; full SEED volume is created from inventory and Mini-SEED data locally. In this case, waveform data from multiple datacenters can be merged into one SEED volume.
Example of a request ﬁle named “req.txt”:
2010,02,18,12,00,00 2010,02,18,12,10,00 GE WLF BH* 2010,02,18,12,00,00 2010,02,18,12,10,00 GE VSU BH*
Submit the request in req.txt to the ArcLink server on st55, and download full SEED data to req.mseed.
> arclink_fetch -a st55:18002 -k fseed -g -u firstname.lastname@example.org -o req.mseed -v req.txt requesting inventory from st55:18002 requesting routing from st55:18002 launching request thread (st55:18002) st55:18002: request 41 ready launching request thread (st14:18002) st14:18002: request 39 ready the following data requests were sent: GFTEST55 Request ID: 41, Label: , Type: WAVEFORM, Args: compression=bzip2 format=MSEED Status: READY, Size: 37137, Info: Volume ID: GFTEST, Status: OK, Size: 37137, Info: Request: 2010,2,18,12,0,0 2010,2,18,12,10,0 GE WLF BHN . Status: OK, Size: 15360, Info: Request: 2010,2,18,12,0,0 2010,2,18,12,10,0 GE WLF BHE . Status: OK, Size: 15360, Info: Request: 2010,2,18,12,0,0 2010,2,18,12,10,0 GE WLF BHZ . Status: OK, Size: 15872, Info: Request: 2010,2,18,12,0,0 2010,2,18,12,10,0 GE VSU BHN . Status: NODATA, Size: 0, Info: Request: 2010,2,18,12,0,0 2010,2,18,12,10,0 GE VSU BHZ . Status: NODATA, Size: 0, Info: Request: 2010,2,18,12,0,0 2010,2,18,12,10,0 GE VSU BHE . Status: NODATA, Size: 0, Info: GFTEST Request ID: 39, Label: , Type: WAVEFORM, Args: compression=bzip2 format=MSEED Status: READY, Size: 46269, Info: Volume ID: GFTEST, Status: OK, Size: 46269, Info: Request: 2010,2,18,12,0,0 2010,2,18,12,10,0 GE VSU BHN . Status: OK, Size: 17408, Info: Request: 2010,2,18,12,0,0 2010,2,18,12,10,0 GE VSU BHZ . Status: OK, Size: 16896, Info: Request: 2010,2,18,12,0,0 2010,2,18,12,10,0 GE VSU BHE . Status: OK, Size: 17408, Info: rebuilding SEED volume
Note that part of the request was routed to secondary server after the primary server returned NODATA.
You can read more about the req.txt (request) file format here.
For installing arclink_fetch onto your system please just choose the appropriate file (deb or rpm) for your system, and you should be able to install it without any problems by just double-clicking the file at the file browser on any modern Linux distribution. Note that during installation you could be asked to install additional packages as dependency, just accept.
For installing arclink_fetch on your Mac you can decompress the file provided into the /usr/local folder. By default this folder doesn't exist and should be created. For doing that:
su - #Your admin/root password will be asked cd /usr mkdir -p local cd local tar xvf <path to>/arclink-fetch.tar or (if your browser didn't decompress the file) tar xvzf <path to>/arclink-fetch.tar.gz
Please also note that for this to work you should have installed Python on your Mac. For checking just type python on the command line and you should get something like:
mbianchi@sec24c79:~> python Python 2.7 (r27:82500, Aug 07 2010, 16:54:59) [GCC] on linux2 Type "help", "copyright", "credits" or "license" for more information. >>>
We have tested it with MacOs 10.6 and python 2.6 and it worked fine. Also, if you want to be able to decrypt encrypted volumes you should also install the M2Crypto egg file into your python using the following command:
To come ...