Comment configurer la journalisation horaire avec pywws¶

Introduction¶

There are two quite different modes of operation with pywws. Traditionally pywws.Hourly would be run at regular intervals (usually an hour) from cron. This is suitable for fairly static websites, but more frequent updates can be useful for sites such as Weather Underground (http://www.wunderground.com/). The newer pywws.LiveLog program runs continuously and can upload data every 48 seconds.

Note that although this document (and the program name) refers to “hourly” logging, you can run pywws.Hourly as often or as infrequently as you like, but don’t try to run it more often than double your logging interval. For example, if your logging interval is 10 minutes, don’t run pywws.Hourly more often than every 20 minutes.

Mise en route¶

Avant tout, vous devez installer pywws et vous assurer qu’il reçoit bien les informations de votre station météo. Voir Comment démarrer avec pywws pour plus de détails.

Try running pywws.Hourly from the command line, with a high level of verbosity so you can see what’s happening. Use the pywws-hourly command to run pywws.Hourly:

pywws-hourly -vvv ~/weather/data

En moins de cinq minutes (assumant que votre intervalle de relevé soit de 5 minutes) vous devriez voir le message “live_data new ptr”, suivi par la recherche et le traitement de nouvelles données de la station météorologique.

Modifié dans la version 14.04.dev1194: the pywws-hourly command replaced scripts/pywws-hourly.py.

Configurer l’emplacement des fichiers¶

Ouvrez votre fichier weather.ini avec un éditeur de texte. Vous devriez avoir une section [paths] similaire à ce qui suit (où xxx est votre nom d’usager):

[paths]
work = /tmp/weather
templates = /home/xxx/weather/templates/
graph_templates = /home/xxx/weather/graph_templates/
local_files = /home/xxx/weather/results/

Edit these to suit your installation and preferences. work is an existing temporary directory used to store intermediate files, templates is the directory where you keep your text template files, graph_templates is the directory where you keep your graph template files and local_files is a directory where template output that is not uploaded to your web site is put. Don’t use the pywws example directories for your templates, as they will get over-written when you upgrade pywws.

Copy your text and graph templates to the appropriate directories. You may find some of the examples provided with pywws useful to get started. The pywws-version -v command should show you where the examples are on your computer.

Nouveau dans la version 14.04.dev1194: the pywws-version command.

Configurer les tâches périodiques¶

Dans weather.ini vous devriez avoir les sections [logged], [hourly], [12 hourly] et [daily] similaires à celle-ci:

[logged]
services = []
plot = []
text = []

[hourly]
...

These specify what pywws.Hourly should do when it is run. Tasks in the [logged] section are done every time there is new logged data, tasks in the [hourly] section are done every hour, tasks in the [12 hourly] section are done twice daily and tasks in the [daily] section are done once per day.

The services entry is a list of online weather services to upload data to. The plot and text entries are lists of template files for plots and text files to be processed and, optionally, uploaded to your web site. Add the names of your template files and weather services to the appropriate entries, for example:

[logged]
services = ['underground', 'metoffice']
plot = []
text = []

[hourly]
services = []
plot = ['7days.png.xml', '24hrs.png.xml', 'rose_24hrs.png.xml']
text = [('tweet.txt', 'T'), '24hrs.txt', '6hrs.txt', '7days.txt']

[12 hourly]
services = []
plot = []
text = []

[daily]
services = []
plot = ['28days.png.xml']
text = [('forecast.txt', 'T'), 'allmonths.txt']

Note the use of the 'T' flag – this tells pywws to send the template result to Twitter instead of uploading it to your ftp site.

You can test that all these are working by removing the [last update] section from status.ini, then running pywws.Hourly again:

pywws-hourly -v ~/weather/data

Nouveau dans la version 14.05.dev1211: [cron name] sections. If you need more flexibility in when tasks are done you can use [cron name] sections. See weather.ini - format du fichier de configuration for more detail.

Modifié dans la version 13.06_r1015: added the 'T' flag. Previously Twitter templates were listed separately in twitter entries in the [hourly] and other sections. The older syntax still works, but is deprecated.

Modifié dans la version 13.05_r1009: the last update information was previously stored in weather.ini, with last update entries in several sections.

Exécuter en tant que tâche “cron”¶

Most UNIX/Linux systems have a “cron” daemon that can run programs at certain times, even if you are not logged in to the computer. You edit a “crontab” file to specify what to run and when to run it. For example, to run pywws.Hourly every hour, at zero minutes past the hour:

0 * * * *       pywws-hourly /home/xxx/weather/data

This might work, but if it didn’t you probably won’t get any error messages to tell you what went wrong. It’s much better to run a script that runs pywws.Hourly and then emails you any output it produces. Here’s the script I use:

#!/bin/sh
#
# weather station logger calling script

export PATH=$PATH:/usr/local/bin

if [ ! -d ~/weather/data/ ]; then
  exit
  fi

log=/var/log/log-weather

pywws-hourly -v ~/weather/data >$log 2>&1

# mail the log file
/home/jim/scripts/email-log.sh $log "weather log"

Vous devrez éditer beaucoup pour adapter à vos emplacements de dossier et ainsi de suite, mais il donne une certaine idée de ce qui peut être fait.

Commentaires et questions? SVP, abonnez-vous à la liste pywws http://groups.google.com/group/pywws et faites-vous entendre.