Beltrachi's blog

[beltrachi]

Google Calendar default calendar for events

When you have to add some events on a calendar and it's not the main calendar (the first on the list), you have to change the calendar selector for every event.

This is ugly and bothering.

So I've developed a Gresemonkey/Tampermonkey script that when you click on the calendar to create a new event, it sets the calendar to the last you saved.

Screen capture with watermark to avoid you getting mad trying to close the popup ;)

Usage: When you are going to create several events on the same calendar, select the desired calendar, save as default, and from now on, all popups for new events will be set to this calendar.

Note: This only affects to the events created in the web interface by clicking on the calendar or through the "New event" button. If you create calendars from your mobile or other calendar apps, they will work as usual.

How to install:

Greasemonkey/Tampermonkey: http://userscripts.org/about/installing

Script http://userscripts.org/scripts/show/180168 (there is a install 

Bon appetit!

[beltrachi]

How to record a webinar or a screencast in Ubuntu 12.04

When you want to record a screencast or a webinar you usually find some issues related with sound.

As my search on Google didn't gave any results on that I'm gonna write it down.

Steps:

Install recordMyDesktop and pavucontrol from repos

run pavucontrol

Go to the "Input devices" tab and change the "Show:" to "All input devices".

Choose "Monitor of built-in" and mark the green ball of "Set as fallback"

Mute the microphone if you do not want to record yourself. (Useful for webinars)

Start recordMyDesktop, activate the sound checkbox and start recording.

Do a test and play the results before recording all the full piece as sometimes you misconfigure something and could lose the chance to record it.

Tips (or don't fail on the same as me)

Block any notification or app that can grab the focus during recording:

Google Gmail web and Google calendar webs. Close all the browsers except the one you want to record.

Stop the automatic updates as explained here: http://www.garron.me/en/linux/turn-off-stop-ubuntu-automatic-update.html but remember to set it back after.

Spotify grabs focus on some events that are not really clear.

Chats that make sounds or can open the window on the top.

In general, close everything else that is running and leave only the required: your cast or your webinar and your recordmydesktop.

[beltrachi]

Backup desktop to S3 for Windows with a custom user

This is what I did to backup my parents desktop and stop worrying about external HDs and other issues.

I use a separate user to not risk or expose the rest of resources.

Steps:

1. Create a bucket called "parents-backup-desktop".

2. Create a custom user on my AWS account for that. I called it "parents" and it will be the user who will have access to that bucket. Trying to keep things tidy.

3. Create a group called "parents" and set the access to be full access to S3 for the bucket we just created.

Add this permission policy to the group: { "Statement": [ { "Sid": "Access to parents backup bucket", "Action": [ "s3:**" ], "Effect": "Allow", "Resource": [ "arn:aws:s3:::parents-backup-desktop", "arn:aws:s3:::parents-backup-desktop/*" ] }, { "Effect": "Allow", "Action": "s3:ListAllMyBuckets", "Resource": "*", "Condition": {} } ] }

4. Add parents user to that group.

5. Install http://www.duplicati.com/home on the desktop to backup.

6. Setup the backup to that bucket

Setup it correctly with the user id and key. On the setup, do not put your user-id before the bucket name.

[beltrachi]

PositiveSSL + nginx + android - Intermediate certificates

At first when you install a PositiveSSL CA2 certificate on an nginx server, android devices will reject the certificate as not trusted.

To fix that you have to concat the PositiveSSLCA2.crt after your certificate.

1. Download the certificate

Download the cert from here https://support.comodo.com/index.php?_m=downloads&_a=viewdownload&downloaditemid=119&nav=0,4

2. Create a bundle certificate

This new crt file will contain the two certificates, your cert first, and the PositiveSSL after.

In my case:

  cat mydomain.crt > bundle.crt

  cat PositiveSSLCA2.crt » bundle.crt

3. Point nginx to the bundle

Update your site config to point to this bundle:

  ssl_certificate      /path/to/your/bundle.crt;

You can see the result here: https://tracks.keskou.com

Why do I have to do this?

Well, when you buy a PositiveSSLCA2 certificate, it says “yoursite.com is trusted by PositiveSSLCA”. But PositiveSSLCA2 is not in your device trusted certificates list.

But luckly, the PositiveSSLCA2 cert has ben trusted by an authority named AddTrustExternalCARoot, which is indeed in android trusted certs list. So we have to show that, yes, you do not know my authority and neither the PositiveSSL but you trust on our parent authority, the AddTrust one. And that’s all.

What we do is append the PositiveSSLCA2, working as intermediate certificate, in the crt file of your site. This means that it will be forwarded to all https connections.

Related links:

http://en.wikipedia.org/wiki/Intermediate_certificate_authorities

http://wiki.nginx.org/HttpSslModule

[beltrachi]

Installing ubuntu on LG P530 K-AE22B

I recently bought this laptop and my experience installing Ubuntu was the following:

First I tried to install Ubuntu 10.04 as its the current LTS, but:

    Wifi did’nt work. It didn’t say anything but didn’t detect my wifi.     Screen wasn’t detected correctly. It showed at 1024x768 and the screen is 1366x768.This didn’t surprise me too much as the hardware here is sort of new.

Next thing to try was to install last Ubuntu released: Ubuntu 11.10The installation was successful and it detected my wifi and my display correctly.

My surprise was the Unity interface … It’s too much interface change for me, as I have to change most ways of accessing applications. Unity needs a review, as it does not seem mature right now. The result:

Ubuntu 11.10 works correctlyand checked the following features:

Wifi OK. If it fails try to activate it by the keyboard specific button.

Screen resolution OK

CPU scaling OK

Audio play and recording OK

Things that had to fix

Backlight screen control. Didn’t work at first, but the workaround came from here: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/803051/comments/3

Sideffect: This now causes that when the screen locks automatically for unactivity and you want to enter again, the backlight is set to 0 so almost nothing can bee seen on the screen. My workaround right now is to type the passw and type enter. This will make you login and you’ll have to go light up by fn keys.

Pending

All tunnings on powertop should tell Good. Now 20 setups appear as “bad”. I tried to fix that with laptop-mode but its not comaptible with kernel 3.x. Now battery lasts about 2h setting CPU profile to powersave.

Backlight issue after screen blanck screensaver.

I’ve been playing around to fix that 2 issues with no luck. I finally decided to wait for Ubuntu 12.04 LTS.

Hardware comments

Good:

The hardware: I5, Geforce, etc.

The style of the whole. Stethically all the other laptops seem big and not elegant.

Bad:

The webcam has no light-indicator when its working. I dunno the reasons but i miss it. Its for privacy, even with the cases of cam hijacking. A pitty really. I’m thinking to stick something there. We’ll see.

Not perfect to be laid on your lap. The width is ok but the hot air flow and the air intakes are set where you use to have your left leg. So I recommend to put it on a flat hard surface. I use it on the train for about an hour without it but It worries me a little bit.

The keyboard could be a little better. It does a little too much noise for me.

I hope you find this kind of review useful. If you need to know something ask me on the comments.

[beltrachi]

Rails WEBrick and android smartphones on localhost

I recently wanted to access my rails project running on localhost from my HTC Desire, through my wireless router.

It didn’t work. The mobile browser started loading the page but the progress bar never reached 100%. No images were loaded.

The workaround I found was to install thin server (gem install thin). I think that it would work as well on mongrel but I’ve not checked.

[beltrachi]

[workaround] Azilink and "Too many open files"

Hi,

I’m using my mobile internet connection to connect my laptop to my computer by an USB wire.

But lately my connection did fall down a lot and in random times. I have no idea what changed to behave like that. I suspect about some apps or some “background sistem configuration change” (the dalvik vm config).

Anyway, the scenario is

High usage of the browser. Opening various tabs from a google search.

Consequences:

The log of the phone started to say “too many connections” as an unknown error. ( See the android logs

The process azilink dies some seconds after.

The connections that were present (Usually XMPP(gmail), Messenger and ssh) do not respond.

The connection is recovered after 5 seconds, as say the phone logs and the openvpn is recovered after that. But after 2 deaths, dalvikvm decides to not recover the process anymore as seems to be unstable.

Here you can see a log example of the “./adb catlog”

E/OSNetworkSystem(10594): unclassified errno 24 (Too many open files) E/OSNetworkSystem(10594): unclassified errno 24 (Too many open files) E/OSNetworkSystem(10594): unclassified errno 24 (Too many open files) E/dalvikvm-gc(10594): Could not create 2248704-byte ashmem mark stack I/ActivityManager(   74): Process org.lfx.azilink.net (pid 10594) has died. D/Zygote  (   50): Process 10594 terminated by signal (11) W/ActivityManager(   74): Scheduling restart of crashed service org.lfx.azilink/.ForwardService in 5000ms I/ActivityManager(   74): Start proc org.lfx.azilink.net for service org.lfx.azilink/.ForwardService: pid=11173 uid=10028 gids={3003, 1015} I/dalvikvm(11173): Debugger thread not active, ignoring DDM send (t=0x41504e4d l=38) I/dalvikvm(11173): Debugger thread not active, ignoring DDM send (t=0x41504e4d l=42) I/InetAddress(11173): gethostbyaddr: getnameinfo: 127.0.0.1 = localhost V/AziLink (11173): AziLink established connection to VPN

Workaround - Browse through a SOCKS 5 proxy

This workaround is intended to reduce the number of connections that goes “in plain” through the VPN.

If we connect to a server that we have on the internet, we’ll send all the conections in the ssh connection and the azilink will have less connections to process.

The web is full of tutorials in how to do that (http://www.google.com/search?q=ssh+socks+5+proxy), but remember that you need a server on internet with ssh access.

That way I got a more persistent azilink connection except when doing videocalls that the phone log shows really weird messages and the connection fails after 10 or 20 minutes.

[beltrachi]

Getting hibernate working on Ubuntu 10.4 on an ACER Aspire 5920 with encrypted swap

Ubuntu 10.4 did suspend correctly but it did’nt resume from hibernate.

The solution is:

1. Add a file on /etc/initramfs-tools/conf.d/ named “resume” with the contents:

RESUME=/dev/mapper/cstorage-lv_swap

Where /dev/mapper/cstorage-lv_swap has to be replaced with your swap partition (see /etc/fstab)

If you have a device by UUID the format would be:

RESUME=UUID=9ced1bec-ed44-4fde-96a6-7c8e29ab35d1

2. Update the initramfs:

sudo update-initramfs -u

After that and without anything else, it got working. I dont realy understand why it has to be done by hand and I’m not sure if the encrypted swap had something to do with it or not, but It finally works.