Tag Archives: software

Aviation, Software Development, Stratux, Technology

STRATUX – Add swap and logging partitions.

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It’s back! The STRAUX project lives again. With a fresh build of Stratux, it’s time to re-configure the SD card for swap space (new!) and a large logging partition to keep a full filesystem from crashing the device.

Get Current Partition Information

Once logged into the Straux box, switch to the root user and interrogate the disk partitions.

pi@raspberrypi: sudo su -
root@raspberrypi: fdisk -l
[...]

Device Boot Start End Sectors Size Type
/dev/mmcblk0p1 8192 131071 122880 60M W95 FAT32 (LBA)
/dev/mmcblk0p2 131072 3700592 3569521 17.G Linux

The important aspects you will want to record as the End block ids for each partition, this is important in the next step, creating more partitions.

Creating the Extended Partition

First task is I want to create the extended partition that can be used for swap. This will eventually contain the swap and log partitions.

Running the fdisk tool, start to edit the partition. You will want to reference the base block of the device.. eg: /dev/mmcblk0

root@raspberrypi: fdisk /dev/mmcblk0

Command (m for help): p

Device Boot Start End Sectors Size Type
/dev/mmcblk0p1 8192 131071 122880 60M W95 FAT32 (LBA)
/dev/mmcblk0p2 131072 3700592 3569521 17.G Linux

Command (m for help): n

Partition type
p primary (2 primary, 0 extended)
l logical (numbered from 5)
Select (default p): l

At this point, the tool threw an error adding partition 5…

Partition 5 is already defined. Delete it before re-adding it

Listing the partitions shows this:

Device Boot Start End Sectors Size Type
/dev/mmcblk0p1 8192 131071 122880 60M W95 FAT32 (LBA)
/dev/mmcblk0p2 131072 3700592 3569521 1.7G Linux
/dev/mmcblk0p3 3700593 62333951 5863d359 28G Extended
/dev/mmcblk0p5 2191 4194446 4192256 2G Linux

Re-running ‘n option and letting it setup partition 6, got me where I wanted to be. This process didn’t seem like it worked right.. but the end result matches up with my goal of a huge partition and a smaller 2G to be used for swap:

Command (m for help): n

Partition type
p primary (2 primary, 0 extended)
l logical (numbered from 5)
Select (default p): l

Adding logical partition 6
First Sector: 4198400
Last Sector: 62333951

Created a new partition 6 of type 'Linux and a size of 27.7 GiB

Command (m for help): p
Device Boot Start End Sectors Size Type
/dev/mmcblk0p1 8192 131071 122880 60M W95 FAT32 (LBA)
/dev/mmcblk0p2 131072 3700592 3569521 1.7G Linux
/dev/mmcblk0p3 3700593 62333951 5863d359 28G Extended
/dev/mmcblk0p5 2191 4194446 4192256 2G Linux
/dev/mmcblk0p6 4198400 62333951 58135552 27.7G Linux

Command (m for help): w

.. this is where the Ending block of your p2 partition number comes into play. The starting sector will be the ending number of your last partition (3569521) + 1 for next sector:


First Sector: 3700593
Last Sector: 62333951 (this was the default/max)

Created a new partition 3 of type 'Extended' and of size 28 GiB

Command (m for help): n

Partition type
p primary (2 primary, 0 extended)
l logical (numbered from 5)
Select (default p): l

Adding the largest partition, for log file storage

Now repeat this process to add the 2nd new partition, this one will consume the rest of the device, and eventually will be where the `/log` directory is mounted.

root@raspberrypi: fdisk /dev/mmcblk0

Command (m for help): p

Device Boot Start End Sectors Size Type
/dev/mmcblk0p1 8192 131071 122880 60M W95 FAT32 (LBA)
/dev/mmcblk0p2 131072 3700592 3569521 1.7G Linux
/dev/mmcblk0p3 3700593 7895039 4194447 2G Extended

Command (m for help): n

Partition type
p primary (2 primary, 0 extended)
l logical (numbered from 5)
Select (default p): l

First Sector: 4194448

Aviation, Software Development, Stratux

STRATUX — Database Log Rotator

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Space in the /var/log directory of a Stratux device, can quickly become consumed, if you don’t have a log management / rotation strategy.

I use a couple of mitigation methods, including a dedicated filesystem for /var/log (so the system does not become unstable and crash).

On the Stratux device itself, I use the following script to auto-rotate the sqlite database file every 24 hours, using a crontab entry.

crontab entry

PATH=/root/go/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

# Run the Stratux DB Rollover
5 6 * * *  /root/stx-rollover.sh >> /var/log/stx-rollover.log
Rotation script

stx-rollover.sh


#!/bin/bash

# Startup Settings
STARTTIME=`date +%m-%d_%T`;
TIMESTAMP=`date +%m-%d`;
LOGPATH="/var/log";
OLDFILE="$LOGPATH/stratux.sqlite";
NEWFILE="$LOGPATH/stratux.sqlite.$TIMESTAMP";

echo "$STARTTIME === Stratux Rollover === "

echo "Stratux STOP"
service stratux stop   

echo "Check for $OLDFILE"
ls -ltr $OLDFILE 

if [ -e "$OLDFILE" ]
then
	echo "Moving $OLDFILE ==> $NEWFILE"
	mv $OLDFILE $NEWFILE
else 
	echo "ERROR - Unable to locate database $OLDFILE"
fi

## Startup Stratux Now.
echo "Stratux START"
service stratux start

if [ -s "$NEWFILE" ]
then
	echo "Moved DB to $NEWFILE"
	ls -l $NEWFILE
	echo "Compressing $NEWFILE"
	gzip $NEWFILE
else 
	echo "ERROR - Unable to locate $NEWFILE" 
fi

echo "Rollover Completed"

End result of this process, is a list of gzipped date stamped databases:


[...]
    152905988 Nov  4 01:05 stratux.sqlite.11-04.gz
    135434058 Nov  6 11:04 stratux.sqlite.11-05.gz
    148176518 Nov  6 11:45 stratux.sqlite.11-06.gz
    157341677 Nov  7 13:10 stratux.sqlite.11-07.gz
[...]

In addition to this logfile rotation strategy, I also pull off these files on a daily basis and archive them to another *NIX based system in my local network. This process is handled using the rsync utility. This process is run every 24 hours, using a cron job on the archival system.

rsync file archiving process

download.dbs.sh


echo '======================================'
date
rsync -a --remove-source-files -e "ssh -l root" 192.100.0.21:/var/log/stratux.sqlite.*.gz /Development/STRATUX/sqlite-dbs/.

This should be a good starting point for your own Stratux logfile management strategy.

Aviation, Software Development, Stratux, Technology

Stratux Webserver – what’s behind the scenes?

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Stratux has a rich community of forums, and a lot of information about debugging Strtux, but so far good hacking information is really hard to find. One of the things of most interest to me was “What is severing up this webpage?”

Every search was a dead end, so I went back to my *NIX system administration roots and thought.. “Well, if someone wont admit what’s serving up the stream.. I’ll find out for myself.

Who’s Your Server? — gen_gdl90

A couple of quick commands told me which PID was hanging onto Port 80 and from there which process was associated with the PID:


root@raspberrypi:~# fuser 80/tcp
80/tcp: 3110
root@raspberrypi:~# ps aux | grep 3110
root 3110 51.9 2.9 973132 27600 ? Ssl 15:19 47:03 /usr/bin/gen_gdl90
root 6606 0.0 0.2 4276 1904 pts/0 S+ 16:50 0:00 grep 3110
What files does it have open?

Once I had an idea of who’m I was looking for, running lsof with the port number gave me 60 entries… and bingo.. there was the nugget of gold I was looking for:


root@raspberrypi:~# lsof -p 3110
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
gen_gdl90 3110 root cwd DIR 179,2 4096 2 /
[...]
gen_gdl90 3110 root 35u IPv6 1849628 0t0 TCP StratuxWiFi.io:http->10.100.0.188:49157 (ESTABLISHED)
gen_gdl90 3110 root 36u IPv6 210216 0t0 TCP StratuxWiFi.io:http->10.100.0.188:64155 (ESTABLISHED)
gen_gdl90 3110 root 37u IPv6 1859641 0t0 TCP StratuxWiFi.io:http->10.100.0.188:49165 (ESTABLISHED)
gen_gdl90 3110 root 38u IPv6 1759876 0t0 TCP StratuxWiFi.io:http->10.100.0.188:65420 (ESTABLISHED)
gen_gdl90 3110 root 41u IPv6 1778784 0t0 TCP StratuxWiFi.io:http->10.100.0.188:65442 (CLOSE_WAIT)
gen_gdl90 3110 root 48r REG 179,2 146998 51146 /var/www/maui/js/angular.min.js
The Web Path

Once onto the trail of the web path, I see that this is an Angular based application (ugh.. I really despise Angular.. I just do.), and all based on some JS stuffs. I get it. for an app like this the two-way data binding of Angular is probably the right too; but I still do not (no do I have to) like it.


root@raspberrypi:~# cd /var/www/maui/
root@raspberrypi:/var/www/maui# ls -l
total 12
drwxr-xr-x 2 root root 4096 Mar 15 2016 css
drwxr-xr-x 2 root root 4096 Mar 15 2016 fonts
drwxr-xr-x 2 root root 4096 Mar 15 2016 js
root@raspberrypi:/var/www/maui#

What I was hoping to find was the location of the that status page.. but.. I believe that what I’m looking for now is the .JS file that manages that label. Initially this looked like a dead end…


root@raspberrypi:/var/www/maui# egrep -r Distance *
root@raspberrypi:/var/www/maui#

Realiazing this was some templating sub-directory, and the root was likely at /var/www, I ran another search that found the location of the desired string, and likely the location of the parts I’m looking for:


root@raspberrypi:~# cd ..
root@raspberrypi:/var/www# egrep -lnr 'Distance' *

plates/js/traffic.js
plates/traffic-help.html
plates/traffic.html

Aviation, Software Development, Stratux, Technology

STRATUX – Filesystem Full; Managing disk space redux

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Checking in with my Starux project this morning, I found it unresponsive. A physical check shows a flashing red light on the Pi… something has gone haywire, and I couldn’t SSH into the little thing, so a really hard cold restart was in order.

Following the restart I quickly shut Stratux back down to start performing diagnostics:


pi@raspberrypi:~ $ sudo su -

root@raspberrypi:~# service stratux stop

Diagnostics 101

Check Filesystem Health

The last time the little Stratux suddenly had problems it was a filesystem space issue ( previous article ). It turns out the boot drive space was OK but the new Logging partition was again, completely consumed:

Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/root        1815440 1391284    331164  81% /
devtmpfs          469688       0    469688   0% /dev
tmpfs             474004       0    474004   0% /dev/shm
tmpfs             474004    6340    467664   2% /run
tmpfs               5120       4      5116   1% /run/lock
tmpfs             474004       0    474004   0% /sys/fs/cgroup
/dev/mmcblk0p1     61384   20400     40984  34% /boot
/dev/mmcblk0p4   8125880 8109496         0 100% /var/log

Locate the Culprit

There are a number of ways to locate large file on a *NIX system. My favorite tool is find. First thing I want to do is locate any file that is larger than 1 Gigabyte, and sure enough it located a massive sqlite database file. The same one that ate up all the space on the boot drive. So.. this is going to require some more extrodinary measures to maintain 100% 24×7 operational status.


root@raspberrypi:~# cd /var/log
root@raspberrypi:/var/log# find . -size +1G -exec ls -l {} \;
-rw-r--r-- 1 root root 7463211008 Apr 29 21:48 ./stratux.sqlite
Start Solving

First order of business is to move aside the massive database, but try to preserve the data for examination. Since the filesystem is full, I can’t zip this thing in place, so first some space needs to cleared on the device. The things I’m least interested in go first.. like the zipped syslogs and any other ‘archived’ file (those with a .# suffix). 

-rw-r----- 1 root adm      728756 Apr 25 06:25 syslog.5.gz
-rw-r----- 1 root adm     2552845 Apr 26 06:25 syslog.4.gz
-rw-r----- 1 root adm     2447263 Apr 27 06:25 syslog.3.gz
-rw-r----- 1 root adm     2498089 Apr 28 06:25 syslog.2.gz
-rw-r----- 1 root adm    33735478 Apr 29 06:25 syslog.1
-rw-r----- 1 root adm       54307 Apr 30 05:19 debug.1
-rw-r----- 1 root adm      380928 Apr 30 05:19 kern.log.1
-rw-r----- 1 root adm   332365824 Apr 30 06:18 daemon.log.1
-rw-r----- 1 root adm       48723 Apr 30 06:25 auth.log.1
-rw-r----- 1 root adm           0 Apr 30 06:25 syslog.1.gz
-rw-r----- 1 root adm     1032192 Apr 30 06:25 messages.1

root@raspberrypi:/var/log# rm -f *.gz *\.[0-9]

But.. that’s not going to doe the complete trick, especially if after deleting files df still shows 100% utilization. You need to figure out what is holding which deleted file(s).

Normallyh, the best way to do that on *NIX is with lsof. Much to my chagrin, it was not available on the OS… so I had to go grab it. Thankfully I had the main filesystem on a different partition that still had enough space to install more tools! Once lsof was installed, grep through the list of open file handles and find those marked for delete.. and those are the processes that have handles pointing to those files. However, this didn’t help me with Rasperian Jessie. I know that a reboot will recover the space so.. that was the next step.. a brutal warm-boot.


root@raspberrypi:/var/log# lsof
-su: lsof: command not found

root@raspberrypi:/# apt-get install lsof
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
libperl4-corelibs-perl
The following NEW packages will be installed:
libperl4-corelibs-perl lsof
...

root@raspberrypi:/var/log# lsof | grep deleted
root@raspberrypi:/var/log#

root@raspberrypi:/var/log# init 6

Archiving Massive SQLite Database

The first thing was to move aside the current database, and then restart stratux to verify it can created a new empty database for it’s purposes.. then shut it right back down again.


root@raspberrypi:/var/log# mv stratux.sqlite stratux.sqlite.1
root@raspberrypi:/var/log# service stratux start
root@raspberrypi:/var/log# ls -l
total 7291480
[...]
-rw-r--r-- 1 root root 4096 Apr 30 14:27 stratux.sqlite
-rw-r--r-- 1 root root 7466160128 Apr 30 14:24 stratux.sqlite.1
[...]
root@raspberrypi:/var/log# service stratux stop

A new empty database file has been created [ 4096 Apr 30 14:27 stratux.sqlite ]. This tells me that moving aside the current database file on a periodic basis, compressing and then archiving it should be sufficient to maintain operational status.

Logging Insanity

Before restarting Stratux, I zerod out these log files. Running for first a few moments these files were already reading up a lot of space. Tailing one of them I see that Stratux, with my current settings is logging A LOT of data to these log files. I feel this was my first error.. enabling too much logging. My settings look like this:

With those settings enabled, there are a lot of GPS and other events that I don’t really have a use for, being dumped into the Statux log.


-rw-r--r-- 1 root root 1361778 Apr 30 14:39 stratux.log

Turning OFF ‘Verbose Message Log’ made that insanity stop.

Replay logging is what is writing to the SQLite database. So the question is. how much of that data do I want to keep, and how much will I lose if I turn off the replay logs. I think that will be research for another day… right now the goal is to recover disk space by compressing the massive database file that was moved aside, and get Stratux stabilized again. Once compressed, check filesystem and file size!


root@raspberrypi:/var/log# gzip stratux.sqlite.1

root@raspberrypi:/var/log# df

Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/root        1815440 1392384    330064  81% /
devtmpfs          469688       0    469688   0% /dev
tmpfs             474004       0    474004   0% /dev/shm
tmpfs             474004   12272    461732   3% /run
tmpfs               5120       4      5116   1% /run/lock
tmpfs             474004       0    474004   0% /sys/fs/cgroup
/dev/mmcblk0p4   8125880  681792   7008276   9% /var/log
/dev/mmcblk0p1     61384   20400     40984  34% /boot

root@raspberrypi:/var/log# ls -lktr --color --block-size=M stratux.sqlite*

-rw-r--r-- 1 root root 643M Apr 30 14:24 stratux.sqlite.1.gz
-rw-r--r-- 1 root root   8M Apr 30 15:21 stratux.sqlite
-rw-r--r-- 1 root root   1M Apr 30 15:22 stratux.sqlite-shm
-rw-r--r-- 1 root root   5M Apr 30 15:22 stratux.sqlite-wal

With the file compressed, it could be copied elsewhere for analysis.

Aviation, Software Development, Stratux, Technology

Stratux – handling a full filesystem

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Running a Stratux in test-bench mode (not in an aircraft, and for days at a time), you’ll likely run into an issue with disk space. The ISO image I acquired from Stratux only provided a 1.8 BG partition for things to live in, and it’s quickly exhausted.

Here is the status of my system after running for about 36 hours… it’s full.

Filesystem Size Used Avail Use% Mounted on
/dev/root 1.8G 1.8G 0 100% /
devtmpfs 459M 0 459M 0% /dev
tmpfs 463M 0 463M 0% /dev/shm
tmpfs 463M 30M 434M 7% /run
tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs 463M 0 463M 0% /sys/fs/cgroup
/dev/mmcblk0p1 60M 20M 41M 34% /boot

Now to get about the business of increasing the partition and filesystem size without destroying it. First

Locate the disk device

Instructions on the web are not exactly correct, some suggest /dev/sda as the main device, however my testing shows it’s actually this named ‘/dev/mmcblk0’.


root@raspberrypi:~# fdisk -l | grep Disk
[...]
Disk /dev/mmcblk0: 14.5 GiB, 15523119104 bytes, 30318592 sectors

… with the following partitions:

Device Boot Start End Sectors Size Id Type
/dev/mmcblk0p1 8192 131071 122880 60M c W95 FAT32 (LBA)
/dev/mmcblk0p2 131072 3887103 3756032 1.8G 83 Linux
Running fdisk

With the physical partition located.. start fdisk:


fdisk /dev/mmcblk0

Welcome to fdisk (util-linux 2.25.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

I ended up creating 3 primary partitions. The plan is to delete partition 3 and then re-size the main partition to use up remaining space:


Device Boot Start End Sectors Size Id Type
/dev/mmcblk0p1 8192 131071 122880 60M c W95 FAT32 (LBA)
/dev/mmcblk0p2 131072 3887103 3756032 1.8G 83 Linux
/dev/mmcblk0p3 2048 8191 6144 3M 5 Extended
/dev/mmcblk0p4 3887104 20664319 16777216 8G 83 Linux

Command (m for help): d
Partition number (1-5, default 5): 3

Partition 3 has been deleted.

Device Boot Start End Sectors Size Id Type
/dev/mmcblk0p1 8192 131071 122880 60M c W95 FAT32 (LBA)
/dev/mmcblk0p2 131072 3887103 3756032 1.8G 83 Linux
/dev/mmcblk0p4 3887104 20664319 16777216 8G 83 Linux

Write out the partition and… then run to enable it:


Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.

partprobe

Next, put a filesystem on this new partition. Using df to determine the type of filesystem currently in use; I recommend that you stick with it for this most basic of operations:


df -T

Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/root ext4 1815440 1799056 0 100% /

Run mkfs


/sbin/mkfs -t ext4 /dev/mmcblk0p4

Creating filesystem with 2097152 4k blocks and 524288 inodes
Filesystem UUID: e36a8f6c-a457-4531-b67d-bea4885a9583
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632

Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information:... this might go on for a bit..

Once completed.. mount this where the logs and databases live. To do this the first thing that needs to happen is to check your current fstab:


cat /etc/fstab
proc /proc proc defaults 0 0
/dev/mmcblk0p1 /boot vfat defaults 0 2
/dev/mmcblk0p2 / ext4 defaults,noatime 0 1
# a swapfile is not a swap partition, no line here
# use dphys-swapfile swap[on|off] for that

My first order of business was to mount the new filesystem to a temporary location (/var/log2) and then copy the contents of /var/log to that location, then delete everything in the log directory, and then unmount log2.


/var/log2

mount -t ext4 /dev/mmcblk0p4 /var/logs

cp -R log/* log2/.

cd log
rm -rf *

umount /dev/mmcblk0p4

Edit the fstab file to create a mount point for the new partition where the logs used to be written (added the orange line), and ran mount to verify that it will automount on a restart.


vi /etc/fstab

proc /proc proc defaults 0 0
/dev/mmcblk0p1 /boot vfat defaults 0 2
/dev/mmcblk0p2 / ext4 defaults,noatime 0 1
/dev/mmcblk0p4 /var/log ext4 defaults,noatime 0 0

mount -a

df

Filesystem 1K-blocks Used Available Use% Mounted on
/dev/root 1815440 1768992 0 100% /
devtmpfs 469688 0 469688 0% /dev
tmpfs 474004 0 474004 0% /dev/shm
tmpfs 474004 35972 438032 8% /run
tmpfs 5120 4 5116 1% /run/lock
tmpfs 474004 0 474004 0% /sys/fs/cgroup
/dev/mmcblk0p1 61384 20400 40984 34% /boot
/dev/mmcblk0p4 8125880 333800 7356268 5% /var/log

Restart and verify

Restart the little box and verify that the mount was preserved.


init 6

Log back in, and run df to check the filesystem health. It should now has the the main filesystem has some breathing room again:

                                                                                              
 ad88888ba  888888888888  88888888ba          db    888888888888  88        88  8b        d8  
d8"     "8b      88       88      "8b        d88b        88       88        88   Y8,    ,8P   
Y8,              88       88      ,8P       d8'`8b       88       88        88    `8b  d8'    
`Y8aaaaa,        88       88aaaaaa8P'      d8'  `8b      88       88        88      Y88P      
  `"""""8b,      88       88""""88'       d8YaaaaY8b     88       88        88      d88b      
        `8b      88       88    `8b      d8""""""""8b    88       88        88    ,8P  Y8,    
Y8a     a8P      88       88     `8b    d8'        `8b   88       Y8a.    .a8P   d8'    `8b   
 "Y88888P"       88       88      `8b  d8'          `8b  88        `"Y8888Y"'   8P        Y8

NOTE TO DEVELOPERS: Make sure that your system has an acceptable clock source, i.e., a GPS
with sufficient signal or enable ntpd (internet connection required).

Everything here comes with ABSOLUTELY NO WARRANTY, to the extent
permitted by applicable law.

Type 'stratux-help' (as root) for a few debugging commands.
pi@raspberrypi:~ $ df

Filesystem 1K-blocks Used Available Use% Mounted on
/dev/root 1815440 1389856 332592 81% /
devtmpfs 469688 0 469688 0% /dev
tmpfs 474004 0 474004 0% /dev/shm
tmpfs 474004 6336 467668 2% /run
tmpfs 5120 16 5104 1% /run/lock
tmpfs 474004 0 474004 0% /sys/fs/cgroup
/dev/mmcblk0p4 8125880 329820 7360248 5% /var/log
/dev/mmcblk0p1 61384 20400 40984 34% /boot

At a later date I’ll work on expanding the main partition, but for now this should stabilize the machine and resolve the main disk consumption issue.

Software Development, Technology

casperJS – passing parameters on the command line (cli)

1 Comment

I like using the command line / shell to pass information to scripts and programs. Sure it has limitations but it’s generally pretty effective.

Each language seems to have it’s own method of handing them, and CasperJS does not seem to be any different. What I did find a little different from others, is how CapserJS splits out arguments from parameters (options in CapserJS speak).

Passing Arguments

Passing arguments is a fairly simple affair. His an example of passing some arguments on the command line to a screen capture utility I’m working on:

casperjs generic.screenshot.cjs http://www.someplace.com save_local
[
“http://www.someplace.com”,
“save_local”
]

They are placed into a list (integer indexed array), and can be addressed in the following way:

url = casper.cli.args[0];
mode = casper.cli.args[1];

This would result in ‘url’ = ‘http://www.someplace.com’ and ‘mode’ = ‘save_local’. Pretty straight forward. One major drawback, you must know the order of the parameters, add a new one, get one out of place and the entire house of cards collapses.

There is a better way!

Passing Parameters (options)

Passing options is a fairly simple affair as well. His an example of passing some option on the command line:

casperjs generic.screenshot.cjs –url=http://www.someplace.com –mode=save_local
{
“casper-path”: “/opt/casperjs”,
“cli”: true,
“url”: “http://www.someplace.com”,
“mode”: “save_local”
}

Note: “casper-path” and “cli” are injected automatically

They are placed into an array, and can be addressed in the following way:

url = casper.cli.options[‘url’];
mode = casper.cli.options[‘mode’];

This would result in ‘url’ = ‘http://www.someplace.com’ and ‘mode’ = ‘save_local’. Now, you do not need to worry about ordering of options, and adding more options doesn’t mean that you’ll have to worry about re-coding the variable localization, ordering etc. It’s also CLEAR to any user how the cli is formatted.

Now, go forth and parse, screen capture and automate your testing until your heart is content!