From Database to exported PNG with R.

gistfile1.r

require( sqlutils )
require( RMySQL )
library( Cairo ) 
library( yaml )

my.cnf = yaml.load_file( '~/.my.yaml' )

default = my.cnf$clients$default
p_cols     <- c( "blue" , "red" , "orange" , "green" ) 
con <- dbConnect(
    MySQL(),
    user=default$user ,
    password=default$password,
    dbname=default$database,
    host=default$host
    )

rs <- dbSendQuery(
    con ,
    '
    SELECT  TIME_FORMAT( time , "%l %p" ) time
        ,   AVG( temp_f ) temperature
    FROM weather
    WHERE HOUR( TIMEDIFF( SYSDATE() , TIME ) ) < 24
    GROUP BY HOUR( time )
    ORDER BY HOUR( TIMEDIFF( SYSDATE() , TIME ) )
    DESC;
    '
    )

fields = dbColumnInfo(rs)
data_frame = fetch(rs, n = 24 )
time = data_frame[[ "time" ]]
temp = data_frame[[ "temperature" ]]

CairoPNG(
    filename="/path/to/where/i/write/test.png" ,
    width = 500 ,
    height = 500 ,
    pointsize = 9
    )
plot (  temp
    ,   main="Temperatures for the last 24 Hours"
    ,   sub="West Lafayette, IN - Temperatures in Fahrenheit"
    ,   col=p_cols[2]
    ,   type="l"
    ,   xlab="Time"
    ,   ylab="Temperature(F)"
    ,   xaxt='n'
    )

axis( 1 , las=2 , at=1:24 ,     lab=time )
box()

Changed the code to read a modified .my.cnf file called .my.yaml which holds the client configuration. This means that my password info gets out of the script. Yay!