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https://github.com/SquareSquash/web

Squash’s front-end and API host.
https://github.com/SquareSquash/web

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Squash’s front-end and API host.

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README 

        
Squash: A squarish bug spray

============================



**An open-source project from [Square](http://github.com/square)**



Squash is a collection of tools that help engineers find and kill bugs in their

code by automatically collecting, collating and analyzing run time exceptions.

Squash consists of the following components:



* **Client libraries:** Client libraries for different systems (Ruby, Ruby on

  Rails, Cocoa with Objective-C, etc.) catch and record errors when they occur,

  then send them to the API endpoint. Client libraries can be found under the

  [SquareSquash organization](https://github.com/SquareSquash).

* **Front-end:** This website displays Bug information and helps the engineer

  find the root cause for a Bug, and fix it. It also lets engineers manage,

  assign, and comment on Bugs, as well as view statistics about the Bug.

* **API endpoints:** These routes (part of the front-end app) receive exception

  notifications from the client libraries and process them.



This project is the front-end and the API.



Pull requests are more than welcome; please check out

[CONTRIBUTING.md](file.CONTRIBUTING.html) for details.



How to Install

--------------



To get started, run the `bin/setup` file. This script will ask you a series of 

questions and generate a preliminary configuration for your site install. When 

the script is completed, you can run `git status` to see what files it changed, 

and refine your configuration from there.



Once the script is complete, Squash should run for most typical development

environments. Simply run `rails s` and visit the site in your Web browser. You

should be able to start using it immediately. You can also verify correctness by

running `rspec spec`.



Configuring and deploying the production instance is entirely up to you and your

particular production environment.



Additional configuration options can be found in the following locations:



* `config/application.rb`

* `config/environments/*.rb`

* `config/environments/*/*.yml`



If you don't see what you're looking for in any of those files, you'll probably

have to change the code to make it work. Don't be afraid -- the code is

thoroughly documented and should (hopefully) be very accessible.



### Requirements



Squash requires the following:



* Ruby 1.9.2 or newer (JRuby with `--1.9` is supported)

* Multithreading support (see the next section)

* PostgreSQL 9.1 or newer

* The Bundler gem

* Git 1.7 or newer



### Notes on some of the gem and library choices



**Why do you specifically require PostgreSQL?** Squash uses a lot of

PostgreSQL-specific features to make efficient use of the database and maintain

referential integrity, such as:



* foreign key constraints,

* triggered cached counters,

* check constraints, and

* semantic indexes for text-based search.



If PostgreSQL is out of the question, some of these features can be ported to

other RDBMSes; simply edit the `InitialSchema` migration and update the SQL as

necessary. If portability is required, a lot of these features can be

reimplemented in the Rails layer (e.g., cached counters), at the risk of

degraded referential integrity. (If you are reimplementing the cached counters

in Ruby, be sure to modify the `config/initializers/active_record.rb` file as

appropriate.)



If you do successfully port Squash to another RDBMS, let me know. I'd be happy

to take your changes.



**Why do you bundle an edge version of Rails?** The `3-2-stable` branch of Ruby

on Rails includes some changes to Active Record that are required by Squash's

multithreaded concurrency model (see next question). In particular, that version

of Active Record includes crucial changes to the connection pool and connection

reopening logic. If you set the `background_runner` option in the

`concurrency.yml` file to something other than `Multithread`, the Gemfile will

automatically drop Rails back down to the latest release version.



**Why don't you use my favorite backgrounding library?** Squash was originally

built for Square, which runs all its services on JRuby. Using threads is very

efficient in JRuby, and avoids the overhead of having to deploy both a website

and workers.



If you are running Squash in a non-thread-safe (or multithreading-unfriendly)

environment, you can use Sidekiq or Resque instead. If you want to use some

other backgrounding library, you can easily write your own adapter. All threaded

code is invoked using {BackgroundRunner.run}, which then uses the settings in

the `concurrency.yml` Configoro file to invoke the correct module under

`lib/background_runner`. The default is to use {BackgroundRunner::Multithread},

which uses the {Multithread} module to execute the task in its own thread. You

can edit the YAML file and switch the background runner to Resque, or implement

your own `BackgroundRunner` module. See the {BackgroundRunner} documentation for

more details.



If you do this successfully and wish to save future Squash users the effort,

feel free to turn your changes into a pull request.



**Why aren't you using RedCarpet?** As mentioned above, Squash was originally

built to run under JRuby. RedCarpet has compiled C extensions; Kramdown is pure

Ruby.



**Why do you require a recent version of Git?** Squash uses the

`git clone --mirror` command to create local mirrors of client projects' Git

repositories.



**Why don't you have integration tests or acceptance tests?** To be 100% honest,

lack of familiarity on these things in Ruby/Rails. Happy for any help people

want to extend towards this goal.



**Why are you using Erector?** I like Erector.



Documentation

-------------



Comprehensive documentation is written in YARD- and Markdown-formatted comments

throughout the source. To view this documentation as an HTML site, run

`rake yard`.



CoffeeScript libraries are documented using the YARD format as well, but YARD

does not as yet recognize them as documentable files. A `.codoopts` file is

included in case you wish to use [Codo](https://github.com/netzpirat/codo) to

generate the CoffeeScript docs, but as of now Codo does not recognize the ERb

files, and does not use the full set of Markdown syntax features used in the

documentation.



Project Overview

----------------



### Views



This is a pretty typical Rails website, save for the views, which are written

using Erector. The views forgo the traditional Rails concepts of partials and

templates in favor of analogous OOP concepts more familiar to software

developers: methods and inheritance. All views inherit from an abstract Erector

widget which provides layout; and all views have their content split into

multiple private methods.



In addition to the usual helpers (in `app/helpers`), there are view mixins under

`app/views/additions` that simplify view coding.



Embedded code snippets are all rendered using the {CommitsController#context}

action. This action loads the appropriate file and revision from the Git

repository and returns a snippet plus the name of the SyntaxHighlighter brush to

use. The brush is determined from the file name/extension; the mapping can be

found in `data/brushes.yml`.



This view behavior is provided from a JavaScript library file in

`lib/assets/javascripts`. There are many similar helper classes in there; they

are documented but the documentation is not recognized by YARD and so is not

included in this documentation set.



JavaScript files are organized into four possible locations:



* Third-party JavaScript libraries are in `vendor/assets/javascripts` and

  loaded in the `application.js` manifest.

* JavaScript modules or helpers that are not specific to a particular page or

  site area are in `lib/assets/javascripts` and also loaded in `application.js`.

* JavaScript modules or helpers specific to a particular area of the site are in

  `app/assets/javascripts` and also loaded in `application.js`.

* Small JavaScript snippets, glue code, or other code intended to add dynamic

  behavior to a specific page is in a `.js` file named the same as, and placed

  alongside, the `.html.rb` view file. For example, if

  `app/views/projects/new.html.rb` needed a bit of JS glue code, it would be

  placed in `app/views/projects/new.js`. This code is placed in a `` tag

  at the end of the view by the {Views::Layouts::Application#inline_javascript}

  method.



CSS files are similarly organized:



* Third-party CSS files are in `vendor/assets/stylesheets` and loaded in the

   `application.css` manifest.

* CSS styles or helpers global to the entire website are in

  `lib/assets/stylesheets` and also loaded in `application.css`.

* CSS styles specific to a single page or a related group of pages are placed in

  `app/assets/stylesheets` and also loaded in `application.css`. Each `<BODY>`

  tag is given a class name equal to the controller name, and an ID equal to

  the controller and action name separated with a dash. For instance, the

  `projects/new` action's body would be `<body class=projects id=projects-new>`.



### Controllers



For information about requests and responses, see {ApplicationController}.



### Models



Models make extensive use of advanced PostgreSQL features for efficiency and

convenience. Cached counters are updated using triggers and rules, foreign key

constraints and hooks are enforced at the database level, and validations are

backed up by corresponding `CHECK` triggers. This helps ensure referential and

data integrity even in situations where Rails fails, or outside of the Rails

stack. See the various migrations to learn more about the triggers, rules, and

constraints being used.



Observers are used for more high-level triggers, such as creating {Event Events}

at the appropriate times, or sending emails. See the classes in

`app/models/observers` for more.



Models also use the HasMetadataColumn gem to reduce their width and incorporate

schemaless data. Most models have a JSON-formatted `metadata` column to which

new information can be added or removed without having to create new migrations.



### Tasks



Various Rake tasks are available under `lib/tasks`. These include tasks for

pruning and maintaining the database, development tasks, and configuring the

workers.



### Workers



Workers are found in the `lib/workers` directory. Along with OccurrencesWorker,

which stores and categorizes Occurrences, there are other workers for managing

Deploys and other minor tasks. These workers are run asynchronously using

{Multithread}.



### Mailers



Notification mails are sent by the {NotificationMailer}. It and any other

mailers live in `app/mailers`.



`NotificationMailer` conditionally delivers emails. An email will only be

delivered if all of the following conditions are met:



* The Project has a mailing list email configured (for the critical-bugs and

  all-bugs mailing lists),

* the Environment's `sends_emails` attribute is `true`, and

* the User has enabled receipt of that category of emails (typically specified

  in the Membership).



### Authentication and Authorization



Authentication is done using either password verification or LDAP; see

{AuthenticationHelpers} and related controller mixins, as well as the

model mixins under `app/models/additions` for more information.



There are four permissions levels that a User can have, specific to an

individual Project:



**Non-members** do not have a {Membership} record with a Project. They can view

Bugs and Occurrences, view the Project's API key, view the list of other

Project members, watch Bugs, and comment on Bugs.



**Members** can do everything non-members can do, and can also assign Bugs, be

assigned Bugs, and modify/delete Bugs.



**Administrators** can do everything members can do, and can also modify

Project and Environment settings, regenerate the API key, promote and demote

members to administrator status, and modify/delete others' Comments.



**Owners** (each Project has only one) can do everything administrators can do,

and can also delete the Project and reassign ownership.



Recording and Categorizing Occurrences

--------------------------------------



### Client-Specific Information



The client library identifiers used throughout the website determine how a Bug

reported from that library is presented in the view. The

{OccurrencesController::INDEX_FIELDS} constant maps a client library identifier

to the relevant summary fields to display in the list view.



Each occurrence is transmitted with the name of the client library; the

{Occurrence} records this to the `client` field. The {Bug}'s `client` field is

set from the first Occurrence's; in general, one should expect that all

Occurrences of a Bug share the same client value.



Regardless of the Occurrence's client value, all fields for which there is data

are displayed in the Occurrence view.



If a client library is updated to add new information fields, all that is needed

is to update the `has_metadata` hash in Occurrence with the new fields, and to

update the `occurrences#show` view as necessary. (The `INDEX_FIELDS` hash can

also be updated as appropriate.)



If a new client library is added, in addition to doing the above for any new

fields unique to the new client, the `INDEX_FIELDS` hash will need to be

expanded to include the new client.



### Queue Consumer



For information about the background worker that converts incoming exception

information into Occurrence and Bug records (including doing "best guess" commit

blaming, determining which Occurrences share the same root Bug, etc.), see the

documentation for the {OccurrencesWorker} module. See also **Static Analysis**

below.



### Deploys and Releases



Squash can handle both _deployed_ projects (hosted projects for which typically

only one version is live at a time) and _released_ projects (distributed apps

for which many versions may exist "in the wild").



If you are developing a released project, you must associate your {Deploy}

objects with a unique version identifier (such as a build number). You must also

send the correct build identifier with every occurrence report. See the client

library and API controller documentation for more information.



Once this is done, Squash's behavior is changed slightly: Bugs that are fixed

in an older release, but recur, are not reopened. Bugs that are fixed in an

older release but then recur in newer releases are treated as completely

separate Bugs.



This app exposes an API endpoint for notifying Squash of new releases/deploys of

your Project. You should notify Squash whenever you deploy your Project (or

release a new version) so that it can properly manage Bugs (automatically mark

fixed Bugs as deployed, associate new Bugs with the new Deploy, etc.).



Most client libraries include an easy means to add this feature to your deploy

or release process.



Static Analysis

---------------



### Message Normalization



When an Occurrence is grouped into a Bug, its message is stripped of any

non-relevant or situational information. (Note that since the message is not

used as a dimension in grouping Occurrences, two Occurrences of the same Bug

could have completely different messages. A Bug gets its message from its first

Occurrence.) This is done by subclasses of {Blamer::Base}.



For most messages, this is done using simple regex subsitution. Squash can also

normalize an exception's message using a list of known message templates. Such

templates are stored in the `data/message_templates.yml` file. The file contains

a hash mapping exception class names to an array of arrays. Each inner array

contains two elements: the regexp to match the exception message on, and the

replacement message should it match.



These templates are evaluated in the order they appear in the array. Scripts

that regenerate the templates for MySQL and PostgreSQL error strings can be

found under the `script` directory.



### Version Control Systems



As of now, Squash is only compatible with projects that are version-controlled

using Git. However, in the interest of remaining as VCS-agnostic as possible,

commit identifiers are never called "SHA1s," but instead "IDs."



### Unsymbolicated, Obfuscated, or Minified Stack Traces



Client libraries of compiled, obfuscated, or minified applications will need to

convert their stack traces in order for them to be of use for static analysis.

Because release builds are typically not distributed with embedded decompilation

information, a mapping or table must be given to Squash, so that when Squash

receives an unconverted stack trace, it can perform lookups and convert it to a

more usable format.



Currently, the supported conversions are:



* symbolication of iOS exceptions (see {Symbolication}),

* deobfuscation of Java exceptions (see {ObfuscationMap}),

* and source-mapping of JavaScript exceptions (see {SourceMap}).



Client libraries are responsible for delivering the raw stack trace data to

Squash when an exception occurs, and for delivering lookup tables to Squash upon

each new release. {Api::V1Controller} has endpoints for these purposes in

various languages.



Unconverted stack traces are stored in a particular format; see {Occurrence} for

more information. When a new exception with a stack trace in this format is

received, Squash immediately attempts to convert it using an existing matching

lookup table. If no such table is found, the stack trace is left unconverted. It

can still be viewed on the front end. When, later, a new lookup table is added,

Squash automatically finds and converts any matching stack traces.



Because every new Occurrence must be assigned a Bug (including unconverted

Occurrences), it is possible that the "blamed" `file` and `line` fields of the

Bug could themselves be unconverted. The {Bug} class has provisions to support

this; see in particular `bugs.special_file`.



Specs

-----



All models, controllers, and library files are unit-tested with RSpec specs

under the `spec` directory. Run unit tests with the `rspec spec` command. Views

and JavaScript files are not specced. No integration or acceptance tests are

written. Almost all unit tests use factories rather than mocks, putting them

somewhat closer to integration tests.



In general, the test environment is identical to the development/production

environment, save for the usual Rails allowances, and the

`config/initializers/active_record_observer_hooks.rb` file. This file adds

after-commit hooks to observers (identical to those available to models).

However, specs are transactionalized, meaning that these hooks wouldn't run

until after the spec is completed, resulting in multiple spec failures.



To remedy this, the file introspects on the environment, and instead links the

observer hooks to the `after_save` model hooks in the test environment. This

differentiates the test and live environments, but allows specs to pass.



If you wish to bring your test environment closer to production, you can set

the `use_transactional_fixtures` RSpec setting to false. The hooks file will

automatically detect the change and use the correct `after_commit` hooks.

Currently, all specs pass with and without transactionalized fixtures.



Third-Party Integrations

------------------------



Squash supports integration with a handful of popular other developer tools.



### PagerDuty



When Squash is integrated with PagerDuty, it will begin sending exceptions to

PagerDuty once the Occurrence count for a given Bug exceeds the Project's

critical threshold. Thereafter, every Occurrence is sent to PagerDuty as a

trigger. The triggers are grouped into alerts by Bug, so users will only be

paged once per new error.



In addition, marking a Bug fixed will also automatically resolve its associated

PagerDuty alert (if any), and assigning a Bug or marking it irrelevant

automatically acknowledges any associated PagerDuty alert.



In order to integrate Squash with PagerDuty, you must



1. generate an API key that Squash can use for PagerDuty access (you must be a

   PagerDuty admin to do this),

2. update the `config/environments/common/pagerduty.yml` file to enable

   PagerDuty integration and provide the API key,

3. configure Generic API services for each escalation policy you wish to use,

   and

4. set the PagerDuty-related options in your Project's configuration page.



### JIRA



When Squash is integrated with JIRA, users have the option of associating a JIRA

issue with any Bug. The Management tab will then display a link allowing the

user to quickly view the associated issue.



In addition, the user can have Squash watch the JIRA issue for status updates.

Once the JIRA issue is resolved (or is changed to someother specified status),

the Bug can be automatically marked as fixed. By associating multiple Bugs with

one JIRA issue in such a manner, a user can quickly fix a large number of Bugs

by closing just one JIRA issue.



Finally, a "Create JIRA Issue" button is provided on the Management tab allowing

users to easily create new JIRA issues for any Bug.



In order to integrate Squash with JIRA, you must



1. configure the `config/environments/common/jira.yml` file with your

   JIRA authentication credentials and installation location, and

2. add a cron job or other periodic task that runs `rake jira:update`.



JIRA integration works out-of-the-box if you use username/password

authentication. OAuth authentication requires a few more steps. Because OAuth

authentication requires user actions, you will need to obtain an access token

and secret which the JIRA client can use without needing to prompt the user. You

can do this by running the `jira_oauth.rb` script:



```` ruby

rails runner script/jira_oauth.rb

````



Follow the instructions to set up your JIRA integration.