Welcome to Trollcast’s documentation!¶

To the source code page.

Trollcast is a tool to exchange polar weather satellite data. It aims at providing near real time data transfer between peers, and should be adaptable to any type of data that is scan-based. At the moments it works on 16-bits hrpt minor frame data (both big and little endian).

The protocol it uses is loosely based on bittorrent.

Warning

This is experimental software, use it at your own risk!

Installing trollcast¶

Download trollcast from the source code page and run:

python setup.py install

Setting up trollcast¶

A trollcast config file describes the different parameters one needs for running both the client and the server.

[local_reception]
localhost=nimbus
remotehosts=safe
data=hrpt
data_dir=/data/hrpt
file_pattern={utctime:%Y%m%d%H%M%S}_{platform:4s}_{number:2s}.temp
max_connections=2
station=norrköping
coordinates=16.148649 58.581844 0.02
tle_files=/var/opt/2met/data/polar/orbitalelements/*.tle
schedule_file=/var/opt/2met/data/polar/schedule/schedule.txt
schedule_format=scisys
mirror=my_receiver_server
output_file=/tmp/{utctime:%Y%m%d%H%M%S}_{platform:4s}_{number:2s}.trollcast.hmf
publisher=trollcast_receiver


[safe]
hostname=172.29.0.236
pubport=9333
reqport=9332

[nimbus]
hostname=172.22.8.16
pubport=9333
reqport=9332

The local_reception section¶

localhost defines the name of the host the process is going to run on locally. This name will be user further down in the configuration file as a section which will hold information about the host. More on this later.

remotehosts is the list of remote hosts to communicate with.

data give the type of data to be exchanged. Only hrpt is available at the moment.

data_dir is the place where streaming data from the reception station is written.

file_pattern is the pattern (trollsift syntax) to use to detect the file that the reception station writes to. Trollcast will watch this file to stream the data to the network in real time.

max_connections tells how many times the data can be sent. This is usefull for avoiding too many clients retrieving the data from the same server, putting unnecessary load on it. Instead, clients will spread the data among each other, creating a more distributed load.

station: name of the station

coordinates: coordinates of the station. Used for the computation of satellite elevation. Lon/lats in degrees, altitude in kilometers.

tle_dir: directory holding the latest TLE data. Used for the computation of satellite elevation.

schedule_file: schedule file to give trollcast server the knowledge of passes to come.

schedule_format: the format of the schedule file. Supported at the moment: scisys and kongsberg_metno.

mirror: the hostname or ip address of the trollcast server the current server has to mirror.

output_file: the file to write data to, in trollsift syntax.

publisher: the name under which to publish new incoming files. If you don’t want to publish anything (which is usually the case when you don’t have a posttroll based trigger to handle messages), just omit this option.

The host sections¶

hostname is the hostname or the ip address of the host.

pubport on which publishing of messages will occur.

reqport on which request and transfer of data will occur.

Modes of operation¶

Server mode, giving out data to the world¶

The server mode is used to serve data to remote hosts.

It is started with:

trollcast_server my_config_file.cfg

This will start a server that watches a given file, as specified in the configuration file. Some options are also available:

usage: trollcast_server [-h] [-l LOG] [-m MAIL] [-v] config_file

positional arguments:
  config_file

optional arguments:
  -h, --help            show this help message and exit
  -l LOG, --log LOG     File to log to.
  -m MAIL, --mail MAIL  Mail to log to.
  -v, --verbose         Print out debug messages also.

Note

In the eventuality that you want to start a sever in gateway mode, that is acting as a gateway to another server, add mirror=name_of_the_primary_server in your configuration file.

Note

Don’t forget to prepend “nohup” to the command if you want to make sure the process doesn’t shut down when you loggout fro the server.

Client mode, retrieving data¶

The client mode retrieves data.

Here is the usage of the client:

usage: trollcast_client [-h] [-t TIMES TIMES] [-o OUTPUT] -f CONFIG_FILE [-v]
                        satellite [satellite ...]

positional arguments:
  satellite             eg. noaa_18

optional arguments:
  -h, --help            show this help message and exit
  -t TIMES TIMES, --times TIMES TIMES
                        Start and end times, <YYYYMMDDHHMMSS>
  -o OUTPUT, --output OUTPUT
                        Output file (used only in conjuction with -t)
  -f CONFIG_FILE, --config_file CONFIG_FILE
                        eg. sattorrent_local.cfg
  -l LOG, --log LOG     File to log to.

  -v, --verbose

There are two ways of running the client:

The first way is to retrieve a given time interval of data. For example, to retrieve data from NOAA 18 for the 14th of November 2012, between 14:02:23 and 14:15:00, the client has to be called with:
```
trollcast_client -t 20121114140223 20121114141500 -o noaa18_20121114140223.hmf -f config_file.cfg noaa_18
```
The second way is to retrieve all the data possible data and dump it to files:
```
trollcast_client -f config_file.cfg noaa_15 noaa_16 noaa_18 noaa_19
```
In this case, only new data will be retrieved though, contrarily to the time interval retrieval where old data will be retrieved too if necessary.

API¶

Client¶

Trollcast client. Leeches all it can :) todo: - connection between institutes is shutdown after a while (2 hours ?) - filename are wrong (1 year to old) - Option for new log file every day? Now log files are quite big after few days. - resets connection to mirror in case of timeout.

class trollcast.client.Client(cfgfile='sattorrent.cfg')¶

The client class.

get_all(satellites)¶: Retrieve all the available scanlines from the stream, and save them.

get_lines(satellite, scanline_dict)¶: Retrieve the best (highest elevation) lines of scanline_dict.

order(time_slice, satellite, filename)¶: Get all the scanlines for a satellite within a time_slice and save them in filename. The scanlines will be saved in a contiguous manner.

send_lineinfo_to_server(*args, **kwargs)¶: Send information to our own server.

stop()¶

class trollcast.client.HaveBuffer(cfgfile='sattorrent.cfg')¶

Listen to incomming have messages.

add_queue(queue)¶: Adds a queue to dispatch have messages to

del_queue(queue)¶: Deletes a dispatch queue.

run()¶

send_to_queues(sat, utctime)¶: Send scanline at utctime to queues.

stop()¶: Stop buffering.

class trollcast.client.RTimer(tries, warning_message, function, *args, **kwargs)¶

alert()¶

reset()¶

run()¶

stop()¶

class trollcast.client.Requester(host, port, station, pubport=None)¶

Make a request connection, waiting to get scanlines .

get_line(satellite, utctime)¶: Get the scanline of satellite at utctime.

get_slice(satellite, start_time, end_time)¶: Get a slice of scanlines.

ping()¶: Send a ping.

recv(timeout=None)¶: Receive a message. timeout in ms.

send(msg)¶: Send a message.

send_lineinfo(sat, utctime, elevation, filename, pos)¶: Send information to our own server.

class trollcast.client.SimpleRequester(host, port)¶

Base requester class.

connect()¶: Connect to the server

request_retries = 3¶

reset_connection()¶: Reset the socket

send_and_recv(msg, timeout=1000000)¶

stop()¶: Close the connection to the server

class trollcast.client.Subscriber(addresses, translate=False)¶

addr_sub¶

recv(timeout=None)¶: Receive a message, timeout in seconds.

reset(addr)¶

stop()¶: Stop the subscriber

sub_addr¶

trollcast.client.compute_line_times(utctime, start_time, end_time)¶: Compute the times of lines if a swath order depending on a reference utctime.

trollcast.client.create_publisher(cfgfile)¶

trollcast.client.create_requesters(cfgfile)¶: Create requesters to all the configure remote hosts.

trollcast.client.create_subscriber(cfgfile)¶: Create a new subscriber for all the remote hosts in cfgfile.

trollcast.client.create_timers(cfgfile, subscriber)¶

trollcast.client.reset_subscriber(subscriber, addr)¶

Server¶

New version of the trollcast server

TODO:

add lines when local client gets data (if missing)
check that mirror server is alive

class trollcast.server.CADU¶

The cadu reader class

static is_it(data)¶

class trollcast.server.Cleaner(holder, delay)¶

Dummy watcher for test purposes

clean()¶: Clean the db

run()¶

stop()¶: Stop adding stuff

class trollcast.server.DummyWatcher(holder, uri)¶

Dummy watcher for test purposes

run()¶

stop()¶: Stop adding stuff

class trollcast.server.FileWatcher(holder, uri, schedule_reader)¶

run()¶

start()¶: Start the file watcher

stop()¶: Stop the file watcher

class trollcast.server.HRPT(sat, reftime)¶

The hrpt reader class

dtype¶

hrpt_sync¶

hrpt_sync_start¶

static is_it(data)¶

line_size = 22180¶

read(data, f_elev=None)¶: Read hrpt data.

satellites = {15: 'NOAA 19', 3: 'NOAA 16', 13: 'NOAA 18', 7: 'NOAA 15'}¶

static timecode(tc_array)¶: HRPT timecode reading

class trollcast.server.Heart(pub, address, interval, schedule_reader)¶

Send heartbeats once in a while.

run()¶

stop()¶: Cardiac arrest

class trollcast.server.Holder(pub, origin)¶

The mighty data holder

add(sat, key, elevation, qual, data)¶: Add some data.

delete(sat, key)¶: Delete item

get(sat, key)¶: get the value of sat and key

get_data(sat, key)¶: get the data of sat and key

get_sat(sat)¶: Get the data for a given satellite sat.

have(sat, key, elevation, qual)¶: Tell the world about our new data.

sats()¶: return the satellites in store.

class trollcast.server.MirrorWatcher(holder, host, pubport, reqport, sched)¶

Watches a other server.

run()¶

stop()¶: Stop the watcher

class trollcast.server.Publisher(port)¶

Publish stuff.

send(message)¶: Publish something

stop()¶: Stop publishing.

class trollcast.server.RequestManager(holder, port, station)¶

Manage requests.

notice(message)¶: Reply to notice message

pong()¶: Reply to ping

run()¶

scanline(message)¶: Reply to scanline request

send(message)¶: Send a message

stop()¶: Stop the request manager.

unknown(message)¶: Reply to any unknown request.

class trollcast.server.ScheduleReader(filename, fileformat)¶

Reads and handles a schedule

get_next_pass()¶: Get the next pass from the schedule

trollcast.server.get_f_elev(satellite)¶: Get the elevation function for a given satellite

trollcast.server.serve(configfile)¶: Serve forever.

trollcast.server.set_subject(station)¶

Schedule readers¶

Read schedule files.

trollcast.schedules.kongsberg_metno(filename)¶: Read a kongsberg schedule

trollcast.schedules.scisys(filename)¶: Read a scisys schedule