somutils 1.5

Tools we use at Somenergia and can be useful

This module includes different Python modules and scripts ubiquiously used on scripts in SomEnergia cooperative but with no entity by themselves to have their own repository.

• venv: run a command under a Python virtual enviroment

• sql2csv.py: script to run parametrized sql queries and get the result as (tab separated) csv.

• dbutils.py: module with db related functions

  • fetchNs: a generator that wraps db cursors to fetch objects with attributes instead of psycopg arrays

  • nsList: uses the former to build a list of such object (slower but maybe convinient)

  • csvTable: turns the results of a query into a tab separated table with proper header names

• sheetfetcher.py: convenience class to retrieve data from gdrive spreadshets

• trace: quickly enable and disable tracing function calling by decorating them with @trace

venv script

This script is useful to run Python scripts under a given virtual environment. It is specially useful to run Python scripts from crontab lines.

usage: venv /PATH/TO/PYTHON/VIRTUALENV COMMAND [PARAM1 [PARAM2...]]

sql2csv.py script

Runs an SQL file and outputs the result of the query as tabulator separated csv.a

You can provide query parameters either as yamlfile or as commandline options.

sql2csv.py <sqlfile> [<yamlfile>] [--<var1> <value1> [--<var2> <value2> ..] ]

dbutils Python module

Convenient cursor wrappers to make the database access code more readable.

Example:

import psycopg2, dbutils
db = psycopg2.connect(**dbconfiguration)
with db.cursor() as cursor :
    cursor.execute("SELECT name, age FROM people")
    for person as dbutils.fetchNs(cursor):
        if person.age < 21: continue
        print("{name} is {age} years old".format(person))

sheetfetcher Python module

Convenient wraper for gdrive.

from sheetfetcher import SheetFetcher

fetcher = SheetFetcher(
    documentName='My Document',
    credentialFilename='drive-certificate.json',
    )
table = fetcher.get_range("My Sheet", "A2:F12")
fulltable = fetcher.get_fullsheet("My Sheet")

• Document selectors can be either an uri or the title

• Sheet selectors can be either an index, a name or an id.

• Range selectors can be either a named range, index tuple or a “A2:F5” coordinates.

• You should Create a certificate and grant it access to the document

trace

This decorator is a fast helper to trace calls to functions and methods. It will show the name of the functions the values of the parameters and the returned values.

from trace import trace

@trace
def factorial(n):
    if n<1: return 1
    return n*factorial(n-1)

factorial(8)

('> factorial', (8,))
('> factorial', (7,))
('> factorial', (6,))
('> factorial', (5,))
('> factorial', (4,))
('> factorial', (3,))
('> factorial', (2,))
('> factorial', (1,))
('> factorial', (0,))
('< factorial', (0,), '->', 1)
('< factorial', (1,), '->', 1)
('< factorial', (2,), '->', 2)
('< factorial', (3,), '->', 6)
('< factorial', (4,), '->', 24)
('< factorial', (5,), '->', 120)
('< factorial', (6,), '->', 720)
('< factorial', (7,), '->', 5040)
('< factorial', (8,), '->', 40320)