sudo apt install python-celery-common

all configuration to run the celery process is put in a python file sometimes called tasks.py

celery -A tasks worker –loglevel=info

But you might have multiple workers named worker1.py and worker2.py so you would start them in two separate shells using

celery -A worker1 worker –loglevel=info
celery -A worker2 worker –loglevel=info

The “functions” you are going to background will be in worker1 or worker2.

In bash, getting a web page

curl https://www.web-atlanta.com/ >html.html

The bash curl command has nothing to do with Canadian Curling, which is like shuffleboard on ice amidst the tension garnered tolerating a joke about the Queen or the national health care system from a surfboard riding processed cheese eating upper Mexican from south of the barbarian line. In bash, curl is short for client url, a simple http request of a web address.

In Python

x = urllib2.urlopen("https://www.web-atlanta.com")
w = x.read()

And as a part of a class init

  def __init__(self,TableName,filename,url):
    self.sqhandle=sqlite3.connect(filename) # empty if noexist
    self.sq1cursor = self.sqhandle.cursor()
    self.filename = filename
    try:
      self.sq1cursor.execute('''CREATE TABLE '''
         +TableName+''' (somenum real, somestring text)''')
      self.sqhandle.commit()
    except:
      print TableName,"table already exists"
    self.samples = 0
    x = urllib2.urlopen(url)
    self.pagedata = x.read()

So if we instantiate a class we now have the html as classname.pagedata and sqlite3 handle and cursor as classname.sqhandle and sq1cursor

We need to do some things with sql like

    command = 'INSERT INTO '+table+' VALUES (' + x +', "'+ y +'")'
    try:
      classname.sq1cursor.execute(command)
      classname.sqhandle.commit()
    except:
      print command

sqlite3 insert a row

  def sqlinsert(sqhandle,sq1cursor,table,x,y):
    command = 'INSERT INTO '+table+' VALUES (' + x +', "'+ y +'")'
    try:
      sq1cursor.execute(command)
      sqhandle.commit()
    except:
      print "failed to ", command

Perl with DBI, Perl Database access

!/usr/bin/perl -w

#

script to add up some table data

use DBI;
use CGI::Carp qw(fatalsToBrowser);

print “Content-type: text/html\n\n”;
my $dbh = DBI->connect(’dbi:mysql:database=DATABASE_NAME;host=localhost’, ‘USERNAME’, ‘PASSWORD’)
or die “Couldn’t connect to database: ” . DBI->errstr;

my ( $k, $id, $book_date, $svc_type, $cust_id, $time_pref, $a_sched,$a_eight);
my $t_date=”20080115″;

$sqlquery = qq( SELECT id, book_date, svc_type, cust_id, time_pref, FROM orders WHERE  move_date = $t_date );
$sth = $dbh->prepare ( $sqlquery );
$sth->execute() || die “Couldn’t execute query: ” . DBI->errstr;

$k = 0;
$sth->bind_columns( \$id, \$book_date, \$svc_type, \$cust_id, \$move_date, \$time_pref, \$est_men, \$est_trks );
while ( $sth->fetch() ) {
$a_sched  += 1;
if ( $time_pref eq “8-9A.M.” ) { $a_eight  +=1; }
}

Now $a_sched contains the number of records $a_eight contains the number of 8-9A.M. record for that date.

atlanta custom database design   vehicle dispatch ERP

On your Linux system with Perl, create this program and chmod it to 755.

#!/usr/bin/perl -w
print "Hello World";

Tuples and lists

Both are arrays, but tuples are immutable. This means that once you define a tuple, you cannot add elements, pop, append, remove an element, etc. You need to create a new tuple out of the old one every time you make a change.

• Tuples (1,2,3,4,5,6) are great for static definition. They are hashable, lean and unequivocal.
• Lists [1,2,3,4,5,6] are great for computation. They are mutable and queueable.

Both are addressed with integers in brackets.

Whether it is a list or a tuple, addressing one element is the same.

create a tuple with y = (“a”,”b”,”c”) and do this;

y = ("a","b","c")
print (y[0])
for i in y:
    print (i)

For lists and tuples, know this too;

for i in range(0,len(y)):
    print (i,y,y[i])

Now redefine y as a list and try it again. Same results?