Sarath Chandra Pandurangi's Blog

The easiest way to install docker on Ubuntu

2014-12-21T19:56:00.000-05:00

Docker releases come out faster than ubuntu updating thier repositories. Docker mainitains a ppa. One can add the ppa key, and then add to sources.list.d and then update sources and then install lxc-docker. OR..

curl -sSL https://get.docker.com/ubuntu/ | sudo sh

Add jquery in Chrome console

2014-03-19T14:53:00.000-04:00

Many a time, a page you are debugging doesnot have jquery. This simple js will add(or prompt you to overwrite) jquery to any page from chrome console.

javascript:if(!window.jQuery||confirm('Overwrite\x20current\x20version?\x20v'+jQuery.fn.jquery))(function(d,s){s=d.createElement('script');s.src='https://ajax.googleapis.com/ajax/libs/jquery/1.8/jquery.js';(d.head||d.documentElement).appendChild(s)})(document);

Podcast: Story of Unconditional Love

2013-12-14T10:58:00.000-05:00

(Source)

SFO goes Gotham, Batkid saves the day!

2013-11-17T12:19:00.000-05:00

SFO gives young Miles, keys to the city Nov 15. Calls the day Batkid day! Batkid saves the day, thumps his fist in the air to the cheering crowds as they burst into joy! What can be a better feelgood story than this one.

Spring MVC: mvn sonar fails when mvn test passes

2013-11-15T12:34:00.000-05:00

Stranger things have happened. But this blows many a mind. mvn test on a restful services project with spring mvc succeeds but mvn sonar:sonar fails with 404s on controllers. This happens when the controllers are marked @transactional for the restful service to be exposed as a unit of work. Don't fret. Its easy to solve this.

This happens because unlike services which are generally proxied by thier interfaces, Controllers are generally defined without interfaces. The Controller methods are then proxied by cglib (when no interfaces exist) and are no longer visible in their qualified name after instrumention by sonar for code analysis.

Just add proxy-target-class="true" instruction to tx annotation driven in the test context. so the testContext.xml should have the following

<tx:annotation-driven proxy-target-class="true"/>

Where as the main application context can remain without proxying

<tx:annotation-driven/>

Happy Halloween (from computer nerds)

2013-10-31T18:32:00.000-04:00

మాస నియామక రూపాత్మక

2013-10-24T07:30:00.000-04:00

మాసం	మాస నియామకం
చైత్రం	శ్రీ పద్మీ విష్ణు
వైశాఖం	శ్రీ కమలా మధుసూధన
జ్యేష్ఠం	శ్రీ రామా త్రివిక్రమ
ఆషాడం	శ్రీ వృశాకపివామన
శ్రావణం	శ్రీ ధన్యా శ్రీధర
భాధ్రపదం	శ్రీ బుద్ధీ హృషీకేశ
ఆశ్వీయుజం	శ్రీ యజ్ఞా పద్మనాభ
కార్తీకం	శ్రీ ఇందిరా దామోదర
మార్గశిరం	శ్రీ శ్రీ కేశవ
పుష్యం	శ్రీ లక్ష్మి నారాయణ
మాఘం	శ్రీ కమలా మాధవ
ఫాల్గుణం	శ్రీ పద్మా గోవింద
అధికమాసం	శ్రీ ఆననందా పురుషోత్తమ

Which way isAssignableFrom ?

2013-07-25T13:41:00.000-04:00

Between java auto boxed types and primitive data types, which way is the class assignable from? Simple.

Long ln = 1L; //autoboxing (assignable)
assertTrue(Number.class.isAssignableFrom(ln.getClass()));
assertTrue(Long.class.isAssignableFrom(ln.getClass()));
assertFalse(long.class.isAssignableFrom(ln.getClass()));

"When we eat animals, they die"

2013-07-20T13:34:00.000-04:00

Cute Boy! Sweet thoughts. Listen to him, go vegetarian.

Enable alwaysUseFullPath with mvc:annotation-driven

2013-07-11T13:23:00.000-04:00

mvc:annotation-driven doesnot have alwaysUseFullPath attribute. However, in instances this is needed, adding the following bean BEFORE mvc:annnotation-driven tag will set up the alwaysUseFullPath correctly

<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping" id="handlerMapping">
        <property name="alwaysUseFullPath" value="true">
</property></bean>

So the fuller xml should like this

<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping" id="handlerMapping">
        <property name="alwaysUseFullPath" value="true">
    </property></bean>
 <mvc:annotation-driven>
  <mvc:message-converters>
   <bean class="org.springframework.http.converter.json.MappingJacksonHttpMessageConverter">
    <property name="objectMapper" ref="jacksonObjectMapper">
    <property name="supportedMediaTypes" value="application/json">
   </property></property></bean>
  </mvc:message-converters>
 </mvc:annotation-driven>


    <mvc:interceptors>
        <bean class="org.springframework.web.servlet.theme.ThemeChangeInterceptor">
        <bean class="org.springframework.web.servlet.i18n.LocaleChangeInterceptor" p:paramname="lang">
        <bean class="org.springframework.web.servlet.mvc.WebContentInterceptor" id="webContentInterceptor" p:alwaysusefullpath="true" p:cacheseconds="0">
            <property name="cacheMappings">
                <props>
                    <prop key="/api/**">0</prop>
                </props>
            </property>
        </bean>
    </bean></bean></mvc:interceptors>

Here's to the original Superman!

2013-06-16T23:49:00.000-04:00

Happy Fathers Day. Miss you.

"Human"

2013-05-24T16:12:00.000-04:00

With all the unreasonable Terror in the world, We should look to Random acts of these "Humans" to be inspired. To have faith, that there is good, still in this world.

Happy Long weekend everyone.

She's Alive... Beautiful... Finite... Hurting... Worth Dying for.

2013-05-05T11:43:00.000-04:00

A Well made movie

Groovy Camel Processors

2013-04-08T20:53:00.000-04:00

Fuse ESB 7.0 comes with Camel 2.9 components. Camel has groovy support from 2.89 to create predicates and expressions. There is a GroovyRouteBuilder in 2.9 that lets you build dsl in groovy, albeit with java api. This is especially un-groovy when you have to write a .process.

Until a more fluent groovy route builder comes to Fuse, Here is a helper that can make writing groovy processes.

class GroovyRoutes extends GroovyRouteBuilder {
 
 @Autowired
 AuthRestTemplate restTemplate; 
 
 void configure() {
  setupGroovyMethods();
  
  from("direct:resource").routeId("groovyRouteWithProcessor")
   .process{ e ->
    //access json and other groovy goodness
    def slurper = new JsonSlurper()
    // do groovy magic with them    
   }
   .to("mock:result");
 
  
 }
 
 def setupGroovyMethods(){
   //setup expandos for later ease
  org.apache.camel.model.RouteDefinition.metaClass.process = { clo ->
    delegate.process(new Processor(){
     public void process(Exchange e) throws Exception {
       clo.call(e)
     }
    });
   }
 }
}

Getting a Java Type Parameter class at runtime

2013-04-03T20:33:00.000-04:00

Certain use cases like deserializing a collection requires knowing the type of the declared field. As the common understanding goes, Type Parameters are erased at build time. So How do we get them?

Its a common misconception that "Type Parameters are erased at build time" - Instead what is actually happening is - Generic collections are converted to raw types. The class definition is NOT modified at build/run time. The Type Parameter(s) can be accessed from the class definition through reflection.

For example:

Lets say here is a Bean

public class Document {
 private List<Model> models;
        ..
}

Given doc, an instance of Document, at runtime, getting the type of doc.models by traditional reflection, can only get that its type is java.util.List

//somewhere in runtime
Document doc = new Document();

 Field f = bean.getClass().getDeclaredField(field);
 f.setAccessible(true);
 assert f.getClass() == List.class

To get the type from parameter, Assuming we know that it is a ParameterizedType (like List<T>)

private <T> Class getListType(T bean, String field) throws NoSuchFieldException {
 Class childType;
 Field f = bean.getClass().getDeclaredField(field);
 f.setAccessible(true);
 childType = (Class) ((ParameterizedType) f.getGenericType()).getActualTypeArguments()[0];
 return childType;
}

//somewhere in runtime
Document doc = new Document();
assert getListType(doc, "models") == Model.class

The same logic can be applied to get multi parameter types (like Map)

 keyType = (Class) ((ParameterizedType) f.getGenericType()).getActualTypeArguments()[0];
 valueType = (Class) ((ParameterizedType) f.getGenericType()).getActualTypeArguments()[1];

There is no such thing: "Just one Photo"

2013-03-30T11:34:00.000-04:00

Trusting Google.

2013-03-20T09:11:00.000-04:00

Consolidating resources to better serve users was the motto behind Google killing various services. But a seriously, Google reader? Reader is one of the first prominent services from Google. It belongs to an elite club that enjoys a loyal use base and plethora of third party apps. What's their fate. On a larger scheme, Is Google trustworthy anymore?

Last week Google released this announcement

We launched Google Reader in 2005 in an effort to make it easy for people to discover and keep tabs on their favorite websites. While the product has a loyal following, over the years usage has declined. So, on July 1, 2013, we will retire Google Reader. Users and developers interested in RSS alternatives can export their data, including their subscriptions, with Google Takeout over the course of the next four months.

First, I was so sure it is a run up to a cruel gag for this year's April 1 (still hoping it is). But now, Google reader is no longer in the "More" menu bar. The truth is slowly sinking in. The phase of denial quickly fading. Very quickly Google became an "unreliable" company. Google killed other "Lab" products before, citing lack of user base. It won't be so easy for Google to wasgh hands off Reader using that excuse. The decision appears to be another failure of Google to understand "Social" - If they had to do this anyway, they probably should have come up with some alternative within Google+ for RSS before announcing the kill.

In the recent past, Companies that put $$$ before innovation are growing by the day - Oracle, Microsoft, Apple, Google.. So if you are an open source developer or otherwise - investing time and resources in API's from them, How sure are you that they will be around?

Now, Google just announced (and released) Keep. Google's take on Evernote. Releasing Keep within a week of Reader's announcement only hurt its chances of launching well into a strong user base. The general dissent towards Google's policy is confusing at best and Alarming at worst. How long will Google keep the other services around. Will it pull the plug on Photos, even Gmail (Google recently removed free version of Google apps for hosting email). Irony is - this and many other blogs that are crying foul on Google's decision are hosted on Google's blogspot.

Yahoo mail improved screen real estate.

2013-02-05T08:56:00.000-05:00

Yahoo mail's make over gave a little breather for long time loyal users like me. Its still leaps and bounds behind Gmail (or for that matter the new outlook.com), But at the very least, the UI developers managed to cleanup a major issue with its header space management.

Before:

They managed to get their act together. moved the controls around and saved at least 20 precious pixels. The controls-unified header now totals 50 px (still high, but) considerbaly less annoying than the previous one which was upwards of 70 px.

After:

The tiny menu items up top are converted to a smartphone style menu icon, which shows more options on a hover popup menu. Over all, it looks slicker. But still is a turn off to look at especially in x-wide screens, where it takes up more space on a percentage basis.

RANT: Wellfargo. Together, we are not going anywhere.

2013-01-07T20:30:00.000-05:00

To Customer Service,

Wells Fargo.

I am at utter dismay with a call I had got off from your customer service.

When we first got our purchase at Bobs financed, we were in it ONLY to build credit history for my wife. As a savvy customer at major banks and financial institutions, I believed this should be easy. 0% apr - monthly online payments and why not, after all, its financed by Wells Fargo a name I trusted at that time. We were asked to register at your old website was wellsfargo.com/retailservices. We were disappointed to see that there was no paperless option, and no account summary details there. The site only serviced online payments. I wanted to make payments from my bank. Naturally I called to ask for online payments time period when I am supposed to pay. I was told to make payments of a minimum of ~$67. So I decided to make $99 to ensure I am NEVER underpaying.

All was well until around Aug or Sept 2012. When the statement was ending earlier or later because of weekend. Unaware of this I kept paying my bills $99 a month. When we finally noticed a late fee levied in November for $25.. We called. My wife was 7 months pregnant at that time, and I was OVERSEAS. Because we were building history we wanted to make sure this was not going to become an issue. So our call finished and we were promised a waiver. Right after we saw another late fee levied this time $35 and the first - not waived yet. So I called in again - December 28th. I spoke to a friendly rep who I had to go through the whole issue - She listened. Got back to me and waived the first $25 and told me that $35 can be waived only by a supervisor and no one is available as I called too late and it was holidays. So she asked me to call after the new years. (during this time, She spoke to my wife and got her authorization to add me to talk on her behalf)

So I call today, I reached a rep (Brian) again in closing hours (after trying to reach repeatedly and being held on hold for long time). I explained the issue - Right off the bat, he had no empathy with us. He wanted to speak to my wife - I figured it was for authorization again. He was insistent that he spoke to my wife and cannot waive fees or even give balance due to me. I told him her condition and she is having a hard time explaining the whole thing over. After a valiant attempt to make him understand what had transpired over the last few months, I took over and asked for final balance to pay off the credit. he pops in a new website for Wells Fargo here it could be self serviced. UNTIL THIS TIME, I WAS NEVER TOLD, THIS COULD BE DONE IN THE NEW WEBSITE and that the migration happened on DECEMBER 14 2012 ( the ONLY good that came out of this call). I made a point to tell him what an awful job he has done, in the following

1. first not showing empathy. especially to a 9 month pregnant lady.
2. an irresponsible handling of the call, not understanding what the customer has to say
3. not honoring the previous representative's word.

I want you to know this is NOT ABOUT $35. but about a reputation of an institution destroyed. I HAVE PAYED OFF the final balance right away from my bank. I am taking time to vent out, because I CAN't let this ride on me. Some one has to know. Track him if you can (call from my phone # initiated around 6:30PM EST approximately 35 mins long inc wait time) - at the very least teach him not to bother pregnant women.

Together, my wife and I are a young and reputable customers (first time in Wells Fargo, but quite seasoned elsewhere) to make financial purchases and decisions big and small. We sure know now, where NOT TO GO.

Update: The site's customer service message tool is just that, a tool. It wont take more than 2000 chars. It appears to be that the message is "don't express yourself all that much, We don't care"!

Promotion very soon: Dad

2013-01-02T08:31:00.000-05:00

Yes. Life is swiftly changing towards even more happiness. This new year, Our family will bring a cute bundle of joy home. We know it is going to be a boy. I'd like to thank my wife for bearing with me during these difficult (but exciting) months. Mom, she is going to be, is such an amazing feeling. She is doing well so far. Dad, me - I am excited, nervous and happy all at the same time.

I'll hope to be back blogging soon.

Happy New Year!

2013-01-01T02:00:00.000-05:00

May this be the year of joy, success, prosperity, peace and harmony for all you.

-Sarath Chandra and Family.

o Flash

2012-06-09T08:30:00.000-04:00

Dedicated to all the dc comic's fans..

Appcache manifest file issues/caveats

2012-06-05T14:42:00.000-04:00

Application cache (appcache) is a powerful feature in HTML5. However, it does come with baggage. Many (see links below) advocated ferociously against it due to tricky issues it comes with. For someone who is just testing waters, these issues may throw them off grid. Knowing them before hand helps reduce some unpredictable effects.

Most important coding caveats about the manifest file and appcache.

The main html file that declares the manifest is ALSO cached in app cache, even if it is not defined in CACHE section. So, if you update the html itself (master), in the manifest must change (a update-time-stamp) to see the changes (also will require user refresh or swapCache call)
If the master is rendered from server and it has varying (seeded or dynamic) parameters, a separate copy of the html is stored in appcache per canonical url (index.php?q=search1, index.php?q=search2 will have separate cached html). This is generally unnecessary, but if you do want to have parameters to pass to javascript, ensure that it is passed via location.hash(e.g: index.php#!q=search1)
Manifest file must begin with the line "CACHE MANIFEST" instruction. Empty lines are treated just like comments in some browsers, so ensure it is the first one
Manifest file must be served with a text/cache-manifest MIME type. Chrome seems to be fine otherwise, but you dont write for chrome alone, do you?
Manifest file must be encoded with 8-bit Unicode Transformation Format (UTF-8) character encoding. This is as per W3C stature, may be easy to do, before you find yourself in trouble.
The path URLs in CACHE section cannot have wildcards. (qualified - relative, canonical and external urls for each resource must be defined separately). URLs in NETWORK and FALLBACK sections can have wildcards (/api will apply for api directory tree; /api/1.html and /api/2.html but not /api2 or /api2/1.html) .
URLs defined in CACHE are all or nothing. This is probably the biggest issue when you use external URLs, your app is now at the mercy of the availability and correct-ness (at the time of caching) of the external providers.
Preferred extension for file is .appcache, however, browsers seem to be fine with anything.
more in gotchas in get-offline, and here.

Some useful links for reading before you rip your hairs out:
Application Cache is a Douchebag
Taking your web sites and apps offline with the HTML5 appcache
Improving app cache
AppCache Wows, Vows & Woes
A Beginner's Guide to using the Application Cache
Debugging HTML 5 Offline Application Cache

C-1, The Electric Bike, coming soon..

2012-05-28T20:20:00.000-04:00

Soon the dream of having a futuristic Electric Motor Cycle will become a reality. The Tron-white vehicle, code-named c-1 and manufactured by lit motors, is foretold to be in showrooms by 2014. The all electric motorcycle will have gyroscope that will eliminate the need to put your foot down for balancing. The expected 200 mile range on a 6 Hr charge is not bad for a Electric Motor Cycle. Innovative technology that integrates with your phone and internet, makes it really futuristic. Did I mention glow light tires?

Here is a sneak peek

3 reasons to migrate to Disqus commenting platform

2012-05-10T22:47:00.000-04:00

Over the last weekend, I evaluated DisQus commenting platform. I saw compelling reasons why Blogger's default commenting is primitive in comparison. Today I am launching DisQus on this blog. Here are 3 most important reasons that made this decision easy.

Larger User(base) engagement
Discus unifies users by multiple login providers. By adding this one widget, Your blog now has Facebook and Twitter users to identify themselves as commentators. They can like and share your posts in their walls and/or tweet them. For users with privacy concerns, comments are also allowed as a Guests. It even has OpenId support (Blogger does too).

Advanced comment posting, replying and moderation
Commenting on DisQus is actually fun. And followup are too. And for the owners, Moderation is much more easier. If you own multiple blogs, you can moderate all of them in one login. Even do it from email (also in Blogger). DisQus has intelligent options to guard your blog from spam. The most important feature is ratings and threads. This way comments with higher ratings and user engagement surfaces well. Users can reply to threads (also available in Blogger), even from their emails. Users love it.

Easy, Simple - Yet, Powerful
Installing is easy, So is importing your existing comments. Installation is completely non-blocking, so your page speed will change negligibly, if at all. There are number of tools to import/export data, show different widgets, even migrate across domains, if necessary.

Bonus: Awesome Support
While I was test driving, I encountered some technical issue. Although DisQus is free, the support is terrific.