Category Archives: Technology

Posts related to technology in general

Bug, fixed: Apparently 40 characters wasn’t enough for a name

Unexpected bug we encountered recently: an attempt to sign up as a Kerika user, using our direct sign up process, failed.

When we looked into the error logged on our server, we discovered that this user was trying to enter a first+last name combination that came to 42 characters; our code assumed that no name would exceed 40 characters in length.

Digging a little further into the user scenario, we discovered that these were accounts that were being opened in the name of organizations, or departments within an organization, rather than actual people.

So while 40 characters may have been enough for most “real people” names, it wasn’t enough for department names, e.g. something like “Kerika Marketing Communications Team”.

Live and learn.

Learning to live with email sandboxing

We spent hours recently trying to understand why a particular user wasn’t able to join her coworkers boards, before finally figuring out that it was her company’s “email sandboxing” that was messing up Kerika’s invitation flow

The problem was a real nuisance to debug, and we fear it will affect more of our users in the future so we are going to make a change to our invitation process to make sure it continues to work well for everyone.

Some background:

“Email sandboxing” refers to a process that tries to trap malicious URLs that are included in emails.  While the exact implementation varies by security vendor, the basic process is the same: use a virtual machine as a sandbox, and click on every URL contained within an email.

This can trap a lot of malware emails.  If the URLs are designed to be single-use only, i.e. the URL is unique and intended to be clicked upon just once, the sandbox will “explode” the mine before the user gets to it.

More sophisticated implementations of sandboxing will handle multi-use URLs by watching for return traffic from the sender’s machine, which would indicate (potential) attempts to download malicious software onto the recipient’s computer.

The problem with sandboxing:

The sandboxing approach takes the same brute force approach to all links, in all emails, without trying to understand the context of the email itself.

One consequence may be that “Unsubscribe” links contained in newsletters are clicked on automatically by the email sandbox virtual machine, so the recipient gets just one copy of a newsletter that she signed up for.

To get around this, systems that generate emails automatically, like a newsletter, have to move from a one-click unsubscribe (which would be more user-friendly) to a two-step unsubscribe process (which is more annoying to the user.)

You will have seen the two-step unsubscribe process more and more often in your own newsletters and other mass mailings: you click on the “Unsubscribe” link in a newsletter, and you land on a web page where you are asked to, once again, confirm that you want to unsubscribe.

The user might think this is a last-ditch attempt by the newsletter publisher to hold on to their readers, but it might actually be an attempt to safeguard the newsletter’s subscribers from their own brute force security implementations!

How this affected Kerika:

When you invite someone to join your Kerika board, as a Team Member, Board Admin or Visitor, the invitation gets sent to them by email as well from within the Kerika app.  The emailed invitation looks like this example:

Example of invitation email

Example of invitation email

The email contains two links: the most prominent is the Accept Invitation, but there’s also the Reject Invitation.

Email sandboxing plays havoc with this sort of email invitation: there is an equal possibility that a particular sandbox will click on the Reject Invitation link before it clicks on the Accept Invitation link, which leads to a completely random experience for users who are being invited by the coworkers to join Kerika boards, since Kerika lets you act just once upon an invitation: once you accept it, or reject it, you can’t act upon it a second time.

How we discovered this problem:

One of our users, based in California ,was trying — repeatedly and unsuccessfully — to invite another user, based in Taiwan, to join one of her boards, and the process kept failing.

And for the longest time we couldn’t figure out why!

Our debugging seemed to suggest Kerika itself was somehow auto-rejecting invitations on the user’s behalf, which had us really worried about a serious bug in the server before one of our developers got the idea that perhaps the problem was with the user’s email system, and not Kerika.

When he examined the headers on an email we got from the affected user, he found references like these:

Received: from mail1.bemta12.messagelabs.com (mail1.bemta12.messagelabs.com [216.82.251.10])

A little more sleuthing led us to Symantec’s “threat protection” service, which is one of the common email sandboxing systems out there.

How we are fixing this:

We are moving to a two-step process for people who want to reject invitations that come to them by email: clicking on the Reject Invitation will now take you to a Web page where you will be asked to confirm that you want to reject the invitation.

It’s one more step for users, and not the kind of superb user experience we aim for, but without this there’s no way for us to make sure that the best intentions of security vendors don’t end up crippling our own business!

Sorry for the disruption in service this morning!

We switched over to Google as the registrar for a number of our domains yesterday (we used to use a mix of GoDaddy and Register.com previously), and in the process our DNS got screwed up.

We didn’t realize this right away because it affected one of our subdomains (which meant the website itself was up and running, but one of the ways in which you can sign into Kerika was messed up.)

The basic problem was with Google’s way of handling incoming transfers of domains that have already been set up: even if you use the setting for keeping your current domains, Google doesn’t keep your current DNS settings for all the subdomains as well.

Our apologies for everyone affected by this!

Update on 10:15AM PST Oct 6:

We are still waiting for Google’s bazillion DNS servers to all get the new DNS entries.  It’s a bit hit-or-miss for individual users, depending upon which Google server they get routed to when they try to login.

Here in the Seattle area, for example, we can login consistently, but we know some of our users can’t. In India it is literally a 50:50 chance that your Kerika session will connect to an updated DNS server or not.  In the UK the problem seems mostly fixed now.

Repro, Cause & Fix: Using Kerika to Fix Bugs

Interested in using Kerika for software development? Here’s a practical example, taken from one of our own boards, that highlights best practices for tracking, investigating and fixing bugs.

First, a look at our Workflow

Every software development team will want to set up its own workflow, of course, reflecting its internal dynamics and available resources.  Here’s the Scrum Board workflow we use in our team:

Scrum Workflow
Scrum Workflow

Our Scrum Boards are organized with these columns:

The Backlog contains all the ideas, large and small, that we have on our product road map: in Scrum terminology, it’s our Product Backlog.

The Sprint Backlog is the set of cards that we pulled from the Backlog at the start of this Sprint: right now, only 4 items are left as we are close to the end of our 2-week Sprint Cycle.

Within each Sprint, cards are picked up developers and first moved into the Planning column, where detailed analysis of the work to be done is completed.

Depending upon the complexity of a particular work item, a developer may request a design review before moving the card further into the Development column.

Developers do their own unit testing as part of the Development phase, but then the work item moves further down to the the QA column which frequently includes formal code review.  (More on that below…)

After a bug has been fixed, had its code reviewed and passed unit testing, it gets Deployed to the Test environment.

We usually wait until the 2-week Sprint is over before asking the entire team to present the entire Sprint’s output to the Product Owner for the Show & Tell; this avoids distracting the team midway through the Sprint.

Once the output of a Sprint has passed the Show & Tell, it can then be Deployed to Production.

The Done column shows all the work that got done in this Sprint.  That’s where all cards are supposed to go, but sometimes a work item is abandoned and moved to the Trash.

(Side note: we sometimes use WIP Limits to make sure that people are not over-committed to work, but this is not a consistent practice within our team.)

Logging the bug

Now, let’s take a look at an example of an actual bug card that was worked on by our team:

Example of a bug tracked as a Kerika card
Example of a bug tracked as a Kerika card

(This particular bug doesn’t have a lot in the details, because it is related to another task that is currently underway, and Kerika makes it easy to link cards, canvases or boards.)

Some bugs go into the Product Backlog, if they are not considered especially urgent, but others go straight into the Sprint Backlog if they represent serious production problems that might affect user’s access or the reliability of their data.

Adding bugs to the Product Backlog lets us process bugs along with other development, e.g. of new features, in the same way: everything can be prioritized by the Product Owner and handled through a consistent workflow.

Documenting the bug

Our bug reports typically come with two attachments; at least one of these should always be included so that the developer has a clear starting point for her work:

  • A screenshot showing the user experience (if the bug can be observed directly by the user.)
  • An excerpt from the error log, if the server reported any errors around the time the bug was observed.
Original bug report documents
Original bug report documents

Kerika makes it easy to attach any kind of content to any card, canvas or board: for bug fixing, particularly in the analysis phase, this is very useful if the user needs to include URLs, material from Sourceforge or similar sites, links to Github, etc.

Repro, Cause & Fix

Before any bug is fixed, our developers always add a standard document we call Repro, Cause and Fix as an attachment to the card:

Repro, Cause and Fix
Repro, Cause and Fix

This document is added no matter how trivial the bug.

Why? Because, on average our team goes through about 30-40 cards a week, and has been doing so for years now.  If we don’t document our analysis now, we will never recall our logic in the future.

Repro, Cause and Fix

Repro, Cause and Fix

Our team adopts a consistent layout of the Repro, Cause & Fix document, which we adhere to even for trivial bugs:

The Repro Steps are the steps needed to trigger the bug: usually they consist of a specific sequence of actions taken by a user that cause the bug to appear, but they can also consist of a sequence of events in the background, like specific server activity or memory/CPU utilization conditions, or overall network traffic, that trigger the bug.

The Expected Behavior helps clarify the developer’s understanding of the how the software should behave in this situation.  It’s not uncommon for a developer who is new to the team to misunderstand how a particular feature is expected to behave, which could lead to more bugs being introduced.  Clarifying Expected Behavior in this document provides an easy way for the Product Owner and the Team Lead to confirm that the developer is not going to go down the wrong track.

Introduced Since: our developers try to pinpoint the specific point in the software’s life where the bug was introduced.  This helps the developers reflect upon how errors are created in the first place: the blind spots lie in their analytical patterns that need to be strengthened.

(In this particular example, the developer has been able to point back to some of her own work on an earlier feature implementation that caused this bug to appear.)

Root Cause is not the same as the Repro Steps.  While a specific sequence of actions or events may reliably display the effects of a particular bug,  they only provide the starting point for the analysis; the Root Cause itself is discovered only when the developer examines the code in detail and determines exactly what is breaking.

Affected Feature: all of our code goes through code review, which we view as one of the most effective QA processes we could adopt, but it can be very challenging when you are processing 30 cards each week, each affecting a different part of the software.

Identifying the Affected Feature helps with the code review process, since the reviewer can consider the bug fix in the larger context of the feature that’s being modified.  Without this, it is doubtful that we could review so many changes each week.

Affected User: in most cases, this is “everyone” we offer the same Kerika  to all our users, whether they are on free trials or have paid for professional subscriptions.

Identifying Affected Users is useful, nonetheless, when dealing with bugs that are browser-specific, or service-specific: for example, determining that a particular bug affects only Kerika+Google users, or only Internet Explorer users.

The Fix: OK, this might seem obvious, but this section really refers to identifying the specific modules in the software that will be changed as a result of the bug fix being applied.

Like many others, we use Git for managing our source code — along with Maven for builds — since our server environment is all Java-based.

Fix
The Fix

The Fix section usually includes references to Git checkins: this helps with future bug fixes, by making it easy to traceback sources of new bugs — part of the Introduced Since section described above.

We use separate Git branches for each feature that we develop so that we can decide precisely what gets released to production, and what is held back for future work.

This helps with the Show & Tell phase of our workflow, when the developers demonstrate the output of the Sprint to the Product Owner, who has the option to accept or reject specific features (i.e. cards on the Scrum Board).

Code Review

All of our code goes through code review, no matter how trivial the change:

Code review
Code review

We really believe that code reviews are one of the most effective QA practices we could adopt: having a second pair of eyes look over code can very considerably reduce the chances of new bugs being introduced.

So…

Kerika is great for distributed software teams: our own team is spread out between Seattle and India (roughly 10,000 miles apart!), and all of our work is done using Kerika for task management, content management and team collaboration.

Of course, an added benefit of “eating our own dogfood” is that we are highly motivated to make sure Kerika is the best tool there is for distributed teams :-)

 

 

How we manage your document versions

Kerika helps you (and your team) manage multiple versions of a document, and it does this so smoothly that you might not even have noticed…

Here’s how it works: when you add a file to a Kerika card or canvas, it shows up in the list of attachments, like this:

File attached to a card
File attached to a card

If you then attach another file to the same card or canvas that has the same name and file type, Kerika automatically treats it as a new version of the same file, rather than a completely different file:

Uploading a new version
Uploading a new version

In the example above, when a Team Member adds another document called Foo.docx to a card that already has a file attached to it with the same name and file type, Kerika treats the new document as a new version of the old Foo.docx rather than as two documents called Foo.docx.

How you access all these old versions depends upon how you set up your Kerika account:

If you are using Kerika+Google, these files are being stored in your Google Drive, and Google will manage the versions for you: you can find this under the File menu in Google Docs

Google Docs versions
Google Docs versions

And pretty much the same thing is true if you are using Kerika+Box: Box will take care of the older versions automatically, although their user interface is slightly different

Box version history
Box version history

And what if you signed up directly with Kerika, without using a Google or Box ID?

We provide an easy way to get to older versions of a file for users who signed up directly: when you are previewing a file, click on the Older versions of this file link on the top-right.

File preview
File preview

Kerika will show you a list of all the old versions that are available for that file, along with details on who uploaded those versions, and when:

Older versions
Older versions

 

Why the files in your Kerika+Box folder have random characters appended to their names

If you are using Kerika+Box, we store your Kerika files in your Box account: you can always go to Box.com, login using your Box ID, and see for yourself.

(But, please, don’t move them around!)

What you might notice is that the filenames in Box have some random characters appended to them. For example, a file that you might see listed inside Kerika as “Alternative Home Page” actually shows up with some random characters appended, like this:

URL appended to file names
URL appended to file names

The reason we do this with files we store in Box — and not for files we store in Google Drive, for our Kerika+Google users, is that Box doesn’t allow for several files within a single folder to have the same name.

(Google does, which is why we don’t need to append any random characters to the files we store in Google Drive.)

It’s very common for our users to have several files within the same board that have the same name: for example, our developers always attach an analysis document to each card that describes exactly what they are doing. (Yes, we are fairly fanatical about documenting our software!)

These documents are often the same for many cards: Analysis.docx or Results.xlsx or Mockup.png might show up hundreds of times within a single board.

Since all the files related to a single Kerika board are stored in the same folder in your Box account, this presents a problem: Box won’t allow for more than one file called Analysis.docx within a folder.

We get around this limitation by appending these random characters, so that effectively every Analysis.docx file has a unique name.

But, we also try to avoid confusing our users, so when we show a list of files attached to a card, we strip out the random characters:

Displaying files as attachments
Displaying files as attachments

And the same goes for downloading files: we strip out the random characters and give you a clean-looking file.

Why this blog uses HTTPS

It’s not that we have sensitive stuff on the blog: quite the contrary. It’s just that we have implemented HTTP Strict Transport Security (HSTS) across the entire kerika.com domain.

HSTS s a security mechanism which helps to protect websites against protocol downgrade attacks and cookie hijacking.

It allows web servers to declare that web browsers should only interact with it using secure HTTPS connections, and never via the insecure HTTP protocol.

Since our blog is on a sub-domain of kerika (blog.kerika.com, to be precise), we needed to implement SSL and HTTPS for the blog as well.

Don’t use snapshots of evolving libraries

Some advice to fellow developers: don’t be tempted to use a local snapshot of a rapidly evolving library, like Polymer.

One of our team members was doing this because he thought it would hasten his compilation when he needed to do new builds of Kerika (he is located in an area with somewhat slow Internet connections).

This might, sort of, work with a very stable library, but with something that is evolving fairly rapidly (like Polymer), you run the far greater risk that you snapshot’ed a somewhat buggy version.

That’s what happened to us, leading to a perplexing day of debugging: we had a version of Polymer that didn’t work well with Internet Explorer 11.

Just our luck that our developer took a snapshot of that particular build and then kept it on his local machine…

Bug, fixed: handling situations where drag-and-drop of content won’t work

The easiest way to attach files to a Kerika card, canvas or board is to simply drag and drop it onto Kerika, like this:

Dragging and dropping files onto cards
Dragging and dropping files onto cards

This works with nearly all kinds of files, but we sometimes hit a limitation, like we discovered when a user tried dragging and dropping an email directly from his Outlook onto Kerika.

This operation used to fail, but in a confusing way: Kerika made it look like it was possible to drop the email onto a card, but the email never showed up.

We have fixed this by checking the kind of content that someone is trying to drop onto Kerika, and if the content isn’t something that can be directly dropped, we don’t show the “drop zone”: the yellow area in the image above that encourages you to drop something onto a card.

And, by the way, if you need to attach an email to a Kerika file, here’s a good workaround: first drag and drop the file onto your computer’s desktop.  That will create a regular file out of the email, which you can then drop onto Kerika.