Ruby: Equal Plus Not Equal to Plus Equal

by Jess Brown

I was recency debugging an issue on an app. I had my test setup and properly failing. I was debugging and narrowing it down to the correct file. I wasn't getting an error or exception, so the specific line number wasn't known. I just knew where the general error was.

I scanned the file, only about 15 lines. I was looping through to some form fields and needed a counter like below:

- if job_skill.id.blank?
  - key = "key#{id}"
  - id =+ 1

If you paid attention to the title or have a sharp eye, you might have noticed the slight difference:

=+ != +=

I would have thought that =+ would cause some sort of exception, but it doesn't:

[1] pry(main)> i = 0
=> 0
[2] pry(main)> i =+ 1
=> 1
[3] pry(main)> i =+ 1
=> 1
[4] pry(main)> i =+ 1
=> 1
[5] pry(main)> i += 1
=> 2
[6] pry(main)> i += 1
=> 3
[7] pry(main)> i += 1
=> 4
[8] pry(main)> i += 1
=> 5
[9] pry(main)>

So, as you can see, my first two results were as expected, but then all future results overwrote the 2nd.

Nice little gotcha to watch out for!

This page is in Tagalog Would you like to translate it?

by Jess Brown

I got a call from a client that reported a strange notification from Google Chrome:

This page is in Tagalog Would you like ot translate it?

It's a feature/function of Google Chrome that will try to guess what language the page is in and then match it to the user's default language. So for example, if an English speaker went to an obvious French site, the same thing would pop down and say the page was in French, would you like to translate it?

What's surprising is that apparently there's a language called Tagalog (did you know??), but, what's confusing is why Chrome thinks this page is written in Tagalog. I hid most of the page, but it just a few simple sentences and some table data.

This is really an issue with Chrome, but after doing a little research, I found I can add some meta tags in to "hint" to Chrome that the site is in English.

I found this page on SO that discusses the same problem. I'm going to try and add these meta tags in:

<meta name="google" content="notranslate" />
<meta http-equiv="Content-Language" content="en_US" />

Hopefully it'll work. Know any other tips??

Rotating rails' logs

by Jess Brown

A few nights ago, I had a rails app running really slow. Users were complaining and sending support tickets to my client. Not my favorite message to get at 11pm!

For reference, it is a rails app, running on unicorn and nginx all on Ubuntu 10.1

One of the first things I did was ssh into the server and ran $ top which will give you a brief overview of the system vitals like memory usage, server load, and top processes. The server load is usually most useful to me. I'm not sure how it works but it's a scale starting with 0. 0-1 and your server is basically idle. 1-3 and your server is humming along fine. When you start getting over 5, your server is probably running noticeably slow. Well, I've seen this number creep up to 15-20 on other servers in the past, this night I was only at a 4-5 range.

The next thing I did was to take a look at the logs. I did an $ ll -h to see what was going on in the direct and got this:

total 1.1G
drwxrwxr-x  2 user group 4.0K 2014-01-23 06:25 ./
drwxrwxr-x 12 user group 4.0K 2012-08-20 08:07 ../
-rw-r--r--  1 user group 1.1G 2014-01-22 06:25 production.log
-rw-r--r--  1 user group  17M 2014-01-22 12:22 unicorn.log

(*I changed the real user/group name with generics to protect my client's and server's idenity)

Whoops, I don't think that log should be quite that large. Each time rails has to write to the log, it is having to deal with a 1G file. I'd actually manually rotated this log, but it was now time to find something more automated.

After checking around a bit, I found this article on stackoverflow talking about a command that I assume comes with most Ubuntu installations called autorotate.

It's actually easy to setup. I just created a file in the /etc/logrotate.d/ directory. This is a config file for autorotate. Mine looked like this:

# /etc/logrotate.d/app_name
# Rotate Rails application logs based on file size
# Rotate log if file greater than 20 MB
/home/user/apps/app_name/current/log/*.log {
    size=20M
    missingok
    rotate 52
    compress
    delaycompress
    notifempty
    copytruncate
}

So it just basically rotates the log when it gets to 20M.

One thing I was unsure of was how the new config would take effect. Did I need to restart the logrotate servce or add the config? It seems that logrotate is cron job run by the system, so you don't need to do anything. It'll just start working.

The other question I had was, where do find the rotated log files? In my case, they were placed in the same directory as the main log file, which was fine because it was sym linked to a 'shared' directory in within my rails app setup.

Now my log direct looks like this after a few days:

total 61.5M
drwxrwxr-x  2 user group 4.0K 2014-01-23 06:25 ./
drwxrwxr-x 12 user group 4.0K 2012-08-20 08:07 ../
-rw-r--r--  1 user group 135K 2014-01-23 09:28 production.log
-rw-r--r--  1 user group  43M 2014-01-23 06:25 production.log.1
-rw-r--r--  1 user group 1.5M 2014-01-22 06:25 production.log.2.gz
-rw-r--r--  1 user group  17M 2014-01-22 12:22 unicorn.log

Hope this helps...feel free to ask questions!

Rails db:migrate error, index is too long

by Jess Brown

The other day I created the following migration:

class CreatePrivateLabelPlanAssignments < ActiveRecord::Migration
  def change
    create_table :private_label_plan_assignments do |t|
      t.belongs_to :private_label_account
      t.belongs_to :plan

      t.timestamps
    end
    add_index :private_label_plan_assignments, :private_label_account_id
    add_index :private_label_plan_assignments, :plan_id
  end
end

When I rake the migration rake db:migrate I got the following error:

-- add_index(:private_label_plan_assignments, :private_label_account_id)
rake aborted!
An error has occurred, this and all later migrations canceled:

Index name
'index_private_label_plan_assignments_on_private_label_account_id' on
table 'private_label_plan_assignments' is too long; the limit is 63
characters/Users/jess/Dropbox/websites/gypsi/gypsi-web/.bundle/gems/ruby/1.9.1/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/schema_statements.rb:573:in
`add_index_options''`

I remembered vaguely running into this issue before, but couldn't remember what the problem was, so I had do to the research all over again. Luckily, I found it rather quickly, but I wanted to write it down somewhere so I could either remember it next time or better reference it. Maybe you'll find it helpful too.

The issue is the add_index method in rails automatically creates an index name in the database. However, the database has it's own limits and in this case, 63 characters is the limit for an index name.

The simple solution is to manually name the index and luckily rails provides that option in the add_index method call. So, just change your migration to have a manual name like so:

class CreatePrivateLabelPlanAssignments < ActiveRecord::Migration
  def change
    create_table :private_label_plan_assignments do |t|
      t.belongs_to :private_label_account
      t.belongs_to :plan

      t.timestamps
    end
    add_index :private_label_plan_assignments, :private_label_account_id, name: "private_label_id"
    add_index :private_label_plan_assignments, :plan_id, name: "plan_id"
  end
end

Hope this helps!

Back Everything UP: Don't get caught with your pants down

by Jess Brown

History

When I first started my company in 2008, my backup plan was simple: I had an external hard drive and I just backed up to it once a week.

After I while that started to become too much of a burden, and I had also setup a Ubuntu dev server that I wanted to try backing client work up to. So I followed this popular article about setting up TimeMachine on Ubuntu and it worked great. Then Rack Space bought a little company called Jungle Disk and they had an option for Unbuntu to backup files to S3 or Rackspace's cloud files for an off site solution.

This worked really well because I had everything in one place and lots of redundancy. I had a 2nd hard drive in the dev server that I rsynced to. I also had another computer in the office that I rsynced to, and I had the offsite backup in case of fire, theft, flood, etc.

What changed?

In 2009, I really started to get into rails development which works best when you have your files locally. You run a local web server, local database server, Git (git is slow over a network for large projects) and things just work better in my local env. Also, I started using Dropbox a lot and enjoyed how easy it was to share files/folders and also came with the convenience of backing up your files automatically in the background. Around that time I also ordered a new dev server with a RAID setup to mirror the data.

This is when things started to get a little off. After setting up my new server, I never resetup JungleDisk. We started putting all new client directories in Dropbox. We ended up with having a lot of old client data on the server, some internal applications (ie billing/time tracking) and lots of old resources (images, videos, etc).

I've had it on my todo list for sometime now to find an offsite solution for my dev server, and I've looked a few times, but just haven't found anything that seemed to fit for what I wanted.

No OS Found

My wife and I take turns each day exercising. Once day she does CrossFit and the next I ride my bike. On Friday's (her day) the CrossFit class is a later in the morning and I usually take some time to hang out with my 3 year old Nate. We were about to go and see my 93 year old grandfather and I was trying to get a deposit ready in the office when Nate came in and simply pushed the power button on my battery backup for the dev server.

I got a little flustered, ushered him out and didn't think much of it (thinking it would reboot itself as it has before after long power outages). Later that afternoon, I went to enter so time in my time tracking app and it wouldn't come up. That's when I went to the server turned the monitor on and saw No OS Found.

I instantly started to get a little nervous. I rebooted and rebooted several time and tried going into the setup and RAID setup and had no luck.

This is when the regret started puring in and I started kicking myself in the rear. How difficult would it have been to just have a simple local copy on one of the other 5-6 machines I have around the office? It wouldn't have taken any more time than to write this article.

The Outcome

I was fortunate that I hadn't lost any client work. I did have a few old client directories that had some graphic source files, but the biggest thing was a months worth of billing / time tracking. How could I ever I recreate that?

This happened on a Friday night, so I couldn't take it immediately anywhere. I was going to wait until Monday, but my anxiety got the best of me and I took it to a place that had done good work for me before, but after taking a quick look, they said it'd be Monday before then had any answers.

Well, this made for a really crumby weekend.

Finally on Monday (afternoon) I got the answer I'd been looking for: my data was safe. There was actually nothing wrong with the hard drives. If we turned off the RAID controller in the BIOS, you could boot the drives fine (so they were perfectly mirrored), but something got messed up with the RAID configuration and it was no longer recognized. You have to erase the HD's to redo the configuration, so I immediately picked up the computer to make backups!

The Takeway

Don't get lazy and slack about your backups...it's easy to do over time, especially if you haven't had a scare in a while. Also, with all the focus on the cloud (Dropbox, Google Apps, S3, etc), it's easy to distance yourself and be naive about how covered you are. I incorrectly felt way too comfortable about the RAID setup and figured I had good coverage and I was very close to being WAY wrong.

Take backing up seriously and don't just rely on one source and/or service.

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