From fa6218c923bd023aac2a502bb34e4541eb82f7e4 Mon Sep 17 00:00:00 2001 From: Mike Gunderloy Date: Sat, 27 Dec 2008 16:15:52 -0600 Subject: Regenerate Guides HTML --- .../guides/html/debugging_rails_applications.html | 277 ++++++++++----------- 1 file changed, 131 insertions(+), 146 deletions(-) (limited to 'railties/doc/guides/html/debugging_rails_applications.html') diff --git a/railties/doc/guides/html/debugging_rails_applications.html b/railties/doc/guides/html/debugging_rails_applications.html index 0653caaf7a..7807da98b7 100644 --- a/railties/doc/guides/html/debugging_rails_applications.html +++ b/railties/doc/guides/html/debugging_rails_applications.html @@ -280,8 +280,8 @@ ul#navMain {

Debugging Rails Applications

-

This guide introduces techniques for debugging Ruby on Rails applications. By referring to this guide, you will be able to:

-
    +

    This guide introduces techniques for debugging Ruby on Rails applications. By referring to this guide, you will be able to:

    +

    • Understand the purpose of debugging @@ -289,7 +289,7 @@ Understand the purpose of debugging

    • -Track down problems and issues in your application that your tests aren't identifying +Track down problems and issues in your application that your tests aren’t identifying

    • @@ -307,8 +307,8 @@ Analyze the stack trace

    1. View Helpers for Debugging

    -

    One common task is to inspect the contents of a variable. In Rails, you can do this with three methods:

    -
      +

      One common task is to inspect the contents of a variable. In Rails, you can do this with three methods:

      +

      • debug @@ -326,7 +326,7 @@ Analyze the stack trace

      1.1. debug

      -

      The debug helper will return a <pre>-tag that renders the object using the YAML format. This will generate human-readable data from any object. For example, if you have this code in a view:

      +

      The debug helper will return a <pre>-tag that renders the object using the YAML format. This will generate human-readable data from any object. For example, if you have this code in a view:

      <p> <b>Title:</b> <%=h @post.title %> -</p> -
      -

      You'll see something like this:

      +</p>
    +

    You’ll see something like this:

    --- !ruby/object:Post
@@ -355,7 +354,7 @@ attributes_cache: {}
 Title: Rails debugging guide

    1.2. to_yaml

    -

    Displaying an instance variable, or any other object or method, in yaml format can be achieved this way:

    +

    Displaying an instance variable, or any other object or method, in yaml format can be achieved this way:

    <p> <b>Title:</b> <%=h @post.title %> -</p> -
    -

    The to_yaml method converts the method to YAML format leaving it more readable, and then the simple_format helper is used to render each line as in the console. This is how debug method does its magic.

    -

    As a result of this, you will have something like this in your view:

    +</p>
+

The to_yaml method converts the method to YAML format leaving it more readable, and then the simple_format helper is used to render each line as in the console. This is how debug method does its magic.

+

As a result of this, you will have something like this in your view:

--- !ruby/object:Post
@@ -384,7 +382,7 @@ attributes_cache: {}
 Title: Rails debugging guide

1.3. inspect

-

Another useful method for displaying object values is inspect, especially when working with arrays or hashes. This will print the object value as a string. For example:

+

Another useful method for displaying object values is inspect, especially when working with arrays or hashes. This will print the object value as a string. For example:

<p> <b>Title:</b> <%=h @post.title %> -</p> -
-

Will be rendered as follows:

+</p>
+

Will be rendered as follows:

[1, 2, 3, 4, 5]
@@ -404,23 +401,21 @@ http://www.gnu.org/software/src-highlite -->
 Title: Rails debugging guide

1.4. Debugging Javascript

-

Rails has built-in support to debug RJS, to active it, set ActionView::Base.debug_rjs to true, this will specify whether RJS responses should be wrapped in a try/catch block that alert()s the caught exception (and then re-raises it).

-

To enable it, add the following in the Rails::Initializer do |config| block inside environment.rb:

+

Rails has built-in support to debug RJS, to active it, set ActionView::Base.debug_rjs to true, this will specify whether RJS responses should be wrapped in a try/catch block that alert()s the caught exception (and then re-raises it).

+

To enable it, add the following in the Rails::Initializer do |config| block inside environment.rb:

-
config.action_view[:debug_rjs] = true
-
-

Or, at any time, setting ActionView::Base.debug_rjs to true:

+
config.action_view[:debug_rjs] = true
+

Or, at any time, setting ActionView::Base.debug_rjs to true:

-
ActionView::Base.debug_rjs = true
-
+
ActionView::Base.debug_rjs = true
@@ -432,27 +427,25 @@ http://www.gnu.org/software/src-highlite -->

2. The Logger

-

It can also be useful to save information to log files at runtime. Rails maintains a separate log file for each runtime environment.

+

It can also be useful to save information to log files at runtime. Rails maintains a separate log file for each runtime environment.

2.1. What is The Logger?

-

Rails makes use of Ruby's standard logger to write log information. You can also substitute another logger such as Log4R if you wish.

-

You can specify an alternative logger in your environment.rb or any environment file:

+

Rails makes use of Ruby’s standard logger to write log information. You can also substitute another logger such as Log4R if you wish.

+

You can specify an alternative logger in your environment.rb or any environment file:

ActiveRecord::Base.logger = Logger.new(STDOUT)
-ActiveRecord::Base.logger = Log4r::Logger.new("Application Log")
-
-

Or in the Initializer section, add any of the following

+ActiveRecord::Base.logger = Log4r::Logger.new("Application Log")
+

Or in the Initializer section, add any of the following

config.logger = Logger.new(STDOUT)
-config.logger = Log4r::Logger.new("Application Log")
-
+config.logger = Log4r::Logger.new("Application Log")
@@ -462,17 +455,16 @@ config.logger =

2.2. Log Levels

-

When something is logged it's printed into the corresponding log if the log level of the message is equal or higher than the configured log level. If you want to know the current log level you can call the ActiveRecord::Base.logger.level method.

-

The available log levels are: :debug, :info, :warn, :error, and :fatal, corresponding to the log level numbers from 0 up to 4 respectively. To change the default log level, use

+

When something is logged it’s printed into the corresponding log if the log level of the message is equal or higher than the configured log level. If you want to know the current log level you can call the ActiveRecord::Base.logger.level method.

+

The available log levels are: :debug, :info, :warn, :error, and :fatal, corresponding to the log level numbers from 0 up to 4 respectively. To change the default log level, use

config.log_level = Logger::WARN # In any environment initializer, or
-ActiveRecord::Base.logger.level = 0 # at any time
-
-

This is useful when you want to log under development or staging, but you don't want to flood your production log with unnecessary information.

+ActiveRecord::Base.logger.level = 0 # at any time +

This is useful when you want to log under development or staging, but you don’t want to flood your production log with unnecessary information.

- +
@@ -482,7 +474,7 @@ ActiveRecord::Base2.3. Sending Messages -

To write in the current log use the logger.(debug|info|warn|error|fatal) method from within a controller, model or mailer:

+

To write in the current log use the logger.(debug|info|warn|error|fatal) method from within a controller, model or mailer:

logger.debug "Person attributes hash: #{@person.attributes.inspect}"
 logger.info "Processing the request..."
-logger.fatal "Terminating application, raised unrecoverable error!!!"
-
-

Here's an example of a method instrumented with extra logging:

+logger.fatal "Terminating application, raised unrecoverable error!!!" +

Here’s an example of a method instrumented with extra logging:

end # ... -end -
-

Here's an example of the log generated by this method:

+end +

Here’s an example of the log generated by this method:

Processing PostsController#create (for 127.0.0.1 at 2008-09-08 11:52:54) [POST]
@@ -537,24 +527,23 @@ The post was saved and now is the user is going to be redirected...
 Redirected to #<Post:0x20af760>
 Completed in 0.01224 (81 reqs/sec) | DB: 0.00044 (3%) | 302 Found [http://localhost/posts]
-

Adding extra logging like this makes it easy to search for unexpected or unusual behavior in your logs. If you add extra logging, be sure to make sensible use of log levels, to avoid filling your production logs with useless trivia.

+

Adding extra logging like this makes it easy to search for unexpected or unusual behavior in your logs. If you add extra logging, be sure to make sensible use of log levels, to avoid filling your production logs with useless trivia.

3. Debugging with ruby-debug

-

When your code is behaving in unexpected ways, you can try printing to logs or the console to diagnose the problem. Unfortunately, there are times when this sort of error tracking is not effective in finding the root cause of a problem. When you actually need to journey into your running source code, the debugger is your best companion.

-

The debugger can also help you if you want to learn about the Rails source code but don't know where to start. Just debug any request to your application and use this guide to learn how to move from the code you have written deeper into Rails code.

+

When your code is behaving in unexpected ways, you can try printing to logs or the console to diagnose the problem. Unfortunately, there are times when this sort of error tracking is not effective in finding the root cause of a problem. When you actually need to journey into your running source code, the debugger is your best companion.

+

The debugger can also help you if you want to learn about the Rails source code but don’t know where to start. Just debug any request to your application and use this guide to learn how to move from the code you have written deeper into Rails code.

3.1. Setup

-

The debugger used by Rails, ruby-debug, comes as a gem. To install it, just run:

+

The debugger used by Rails, ruby-debug, comes as a gem. To install it, just run:

-
$ sudo gem install ruby-debug
-
-

In case you want to download a particular version or get the source code, refer to the project's page on rubyforge.

-

Rails has had built-in support for ruby-debug since Rails 2.0. Inside any Rails application you can invoke the debugger by calling the debugger method.

-

Here's an example:

+
$ sudo gem install ruby-debug
+

In case you want to download a particular version or get the source code, refer to the project’s page on rubyforge.

+

Rails has had built-in support for ruby-debug since Rails 2.0. Inside any Rails application you can invoke the debugger by calling the debugger method.

+

Here’s an example:

debugger @person = Person.new end -end -
-

If you see the message in the console or logs:

+end +

If you see the message in the console or logs:

***** Debugger requested, but was not available: Start server with --debugger to enable *****
-

Make sure you have started your web server with the option —debugger:

+

Make sure you have started your web server with the option --debugger:

=> Booting Mongrel (use 'script/server webrick' to force WEBrick) => Rails 2.2.0 application starting on http://0.0.0.0:3000 => Debugger enabled -... -
+...
- +
Tip In development mode, you can dynamically require 'ruby-debug' instead of restarting the server, if it was started without —debugger.In development mode, you can dynamically ‘require 'ruby-debug\’ instead of restarting the server, if it was started without `--debugger.
-

In order to use Rails debugging you'll need to be running either WEBrick or Mongrel. For the moment, no alternative servers are supported.

+

In order to use Rails debugging you’ll need to be running either WEBrick or Mongrel. For the moment, no alternative servers are supported.

3.2. The Shell

-

As soon as your application calls the debugger method, the debugger will be started in a debugger shell inside the terminal window where you launched your application server, and you will be placed at ruby-debug's prompt (rdb:n). The n is the thread number. The prompt will also show you the next line of code that is waiting to run.

-

If you got there by a browser request, the browser tab containing the request will be hung until the debugger has finished and the trace has finished processing the entire request.

-

For example:

+

As soon as your application calls the debugger method, the debugger will be started in a debugger shell inside the terminal window where you launched your application server, and you will be placed at ruby-debug’s prompt (rdb:n). The n is the thread number. The prompt will also show you the next line of code that is waiting to run.

+

If you got there by a browser request, the browser tab containing the request will be hung until the debugger has finished and the trace has finished processing the entire request.

+

For example:

@posts = Post.find(:all)
 (rdb:7)
-

Now it's time to explore and dig into your application. A good place to start is by asking the debugger for help… so type: help (You didn't see that coming, right?)

+

Now it’s time to explore and dig into your application. A good place to start is by asking the debugger for help... so type: help (You didn’t see that coming, right?)

(rdb:7) help
@@ -621,11 +608,11 @@ continue   edit     frame   method  putl  set      tmate   where
 Tip To view the help menu for any command use help <command-name> in active debug mode. For example: help varTo view the help menu for any command use help <command-name> in active debug mode. For example: +help var+
-

The next command to learn is one of the most useful: list. You can also abbreviate ruby-debug commands by supplying just enough letters to distinguish them from other commands, so you can also use l for the list command.

-

This command shows you where you are in the code by printing 10 lines centered around the current line; the current line in this particular case is line 6 and is marked by ⇒.

+

The next command to learn is one of the most useful: list. You can also abbreviate ruby-debug commands by supplying just enough letters to distinguish them from other commands, so you can also use l for the list command.

+

This command shows you where you are in the code by printing 10 lines centered around the current line; the current line in this particular case is line 6 and is marked by =>.

(rdb:7) list
@@ -641,7 +628,7 @@ continue   edit     frame   method  putl  set      tmate   where
9 format.html # index.html.erb 10 format.xml { render :xml => @posts }
-

If you repeat the list command, this time using just l, the next ten lines of the file will be printed out.

+

If you repeat the list command, this time using just l, the next ten lines of the file will be printed out.

(rdb:7) l
@@ -657,11 +644,11 @@ continue   edit     frame   method  putl  set      tmate   where
19 respond_to do |format| 20 format.html # show.html.erb
-

And so on until the end of the current file. When the end of file is reached, the list command will start again from the beginning of the file and continue again up to the end, treating the file as a circular buffer.

+

And so on until the end of the current file. When the end of file is reached, the list command will start again from the beginning of the file and continue again up to the end, treating the file as a circular buffer.

3.3. The Context

-

When you start debugging your application, you will be placed in different contexts as you go through the different parts of the stack.

-

ruby-debug creates a content when a stopping point or an event is reached. The context has information about the suspended program which enables a debugger to inspect the frame stack, evaluate variables from the perspective of the debugged program, and contains information about the place where the debugged program is stopped.

-

At any time you can call the backtrace command (or its alias where) to print the backtrace of the application. This can be very helpful to know how you got where you are. If you ever wondered about how you got somewhere in your code, then backtrace will supply the answer.

+

When you start debugging your application, you will be placed in different contexts as you go through the different parts of the stack.

+

ruby-debug creates a content when a stopping point or an event is reached. The context has information about the suspended program which enables a debugger to inspect the frame stack, evaluate variables from the perspective of the debugged program, and contains information about the place where the debugged program is stopped.

+

At any time you can call the backtrace command (or its alias where) to print the backtrace of the application. This can be very helpful to know how you got where you are. If you ever wondered about how you got somewhere in your code, then backtrace will supply the answer.

(rdb:5) where
@@ -675,18 +662,18 @@ continue   edit     frame   method  putl  set      tmate   where
at line /PathTo/project/vendor/rails/actionpack/lib/action_controller/filters.rb:617 ...
-

You move anywhere you want in this trace (thus changing the context) by using the frame n command, where n is the specified frame number.

+

You move anywhere you want in this trace (thus changing the context) by using the frame n command, where n is the specified frame number.

(rdb:5) frame 2
 #2 ActionController::Base.perform_action_without_filters
        at line /PathTo/project/vendor/rails/actionpack/lib/action_controller/base.rb:1175
-

The available variables are the same as if you were running the code line by line. After all, that's what debugging is.

-

Moving up and down the stack frame: You can use up [n] (u for abbreviated) and down [n] commands in order to change the context n frames up or down the stack respectively. n defaults to one. Up in this case is towards higher-numbered stack frames, and down is towards lower-numbered stack frames.

+

The available variables are the same as if you were running the code line by line. After all, that’s what debugging is.

+

Moving up and down the stack frame: You can use up [n] (u for abbreviated) and down [n] commands in order to change the context n frames up or down the stack respectively. n defaults to one. Up in this case is towards higher-numbered stack frames, and down is towards lower-numbered stack frames.

3.4. Threads

-

The debugger can list, stop, resume and switch between running threads by using the command thread (or the abbreviated th). This command has a handful of options:

-
    +

    The debugger can list, stop, resume and switch between running threads by using the command thread (or the abbreviated th). This command has a handful of options:

    +

    • thread shows the current thread. @@ -713,17 +700,17 @@ continue edit frame method putl set tmate where

    -

    This command is very helpful, among other occasions, when you are debugging concurrent threads and need to verify that there are no race conditions in your code.

    +

    This command is very helpful, among other occasions, when you are debugging concurrent threads and need to verify that there are no race conditions in your code.

    3.5. Inspecting Variables

    -

    Any expression can be evaluated in the current context. To evaluate an expression, just type it!

    -

    This example shows how you can print the instance_variables defined within the current context:

    +

    Any expression can be evaluated in the current context. To evaluate an expression, just type it!

    +

    This example shows how you can print the instance_variables defined within the current context:

    @posts = Post.find(:all)
 (rdb:11) instance_variables
 ["@_response", "@action_name", "@url", "@_session", "@_cookies", "@performed_render", "@_flash", "@template", "@_params", "@before_filter_chain_aborted", "@request_origin", "@_headers", "@performed_redirect", "@_request"]
    -

    As you may have figured out, all of the variables that you can access from a controller are displayed. This list is dynamically updated as you execute code. For example, run the next line using next (you'll learn more about this command later in this guide).

    +

    As you may have figured out, all of the variables that you can access from a controller are displayed. This list is dynamically updated as you execute code. For example, run the next line using next (you’ll learn more about this command later in this guide).

    (rdb:11) next
@@ -733,13 +720,13 @@ Processing PostsController#index (for 127.0.0.1 at 2008-09-04 19:51:34) [GET]
 /PathToProject/posts_controller.rb:8
 respond_to do |format|
    -

    And then ask again for the instance_variables:

    +

    And then ask again for the instance_variables:

    (rdb:11) instance_variables.include? "@posts"
 true
    -

    Now @posts is a included in the instance variables, because the line defining it was executed.

    +

    Now @posts is a included in the instance variables, because the line defining it was executed.

    @@ -748,7 +735,7 @@ true You can also step into irb mode with the command irb (of course!). This way an irb session will be started within the context you invoked it. But be warned: this is an experimental feature.
    -

    The var method is the most convenient way to show variables and their values:

    +

    The var method is the most convenient way to show variables and their values:

    var
@@ -757,13 +744,13 @@ true
    (rdb:1) v[ar] i[nstance] <object> show instance variables of object (rdb:1) v[ar] l[ocal] show local variables
    -

    This is a great way to inspect the values of the current context variables. For example:

    +

    This is a great way to inspect the values of the current context variables. For example:

    (rdb:9) var local
   __dbg_verbose_save => false
    -

    You can also inspect for an object method this way:

    +

    You can also inspect for an object method this way:

    (rdb:9) var instance Post.new
@@ -779,16 +766,16 @@ true
The commands p (print) and pp (pretty print) can be used to evaluate Ruby expressions and display the value of variables to the console.
-

You can use also display to start watching variables. This is a good way of tracking the values of a variable while the execution goes on.

+

You can use also display to start watching variables. This is a good way of tracking the values of a variable while the execution goes on.

(rdb:1) display @recent_comments
 1: @recent_comments =
-

The variables inside the displaying list will be printed with their values after you move in the stack. To stop displaying a variable use undisplay n where n is the variable number (1 in the last example).

+

The variables inside the displaying list will be printed with their values after you move in the stack. To stop displaying a variable use undisplay n where n is the variable number (1 in the last example).

3.6. Step by Step

-

Now you should know where you are in the running trace and be able to print the available variables. But lets continue and move on with the application execution.

-

Use step (abbreviated s) to continue running your program until the next logical stopping point and return control to ruby-debug.

+

Now you should know where you are in the running trace and be able to print the available variables. But lets continue and move on with the application execution.

+

Use step (abbreviated s) to continue running your program until the next logical stopping point and return control to ruby-debug.

@@ -797,9 +784,9 @@ true You can also use step+ n and step- n to move forward or backward n steps respectively.
-

You may also use next which is similar to step, but function or method calls that appear within the line of code are executed without stopping. As with step, you may use plus sign to move n steps.

-

The difference between next and step is that step stops at the next line of code executed, doing just a single step, while next moves to the next line without descending inside methods.

-

For example, consider this block of code with an included debugger statement:

+

You may also use next which is similar to step, but function or method calls that appear within the line of code are executed without stopping. As with step, you may use plus sign to move n steps.

+

The difference between next and step is that step stops at the next line of code executed, doing just a single step, while next moves to the next line without descending inside methods.

+

For example, consider this block of code with an included debugger statement:

:limit => limit ) end -end -
+end
@@ -839,7 +825,7 @@ Loading development environment (Rails 2.1.0) /PathTo/project/app/models/author.rb:11 ) -

With the code stopped, take a look around:

+

With the code stopped, take a look around:

(rdb:1) list
@@ -853,14 +839,14 @@ Loading development environment (Rails 2.1.0)
    12    end
    13  end
-

You are at the end of the line, but… was this line executed? You can inspect the instance variables.

+

You are at the end of the line, but... was this line executed? You can inspect the instance variables.

(rdb:1) var instance
 @attributes = {"updated_at"=>"2008-07-31 12:46:10", "id"=>"1", "first_name"=>"Bob", "las...
 @attributes_cache = {}
-

@recent_comments hasn't been defined yet, so it's clear that this line hasn't been executed yet. Use the next command to move on in the code:

+

@recent_comments hasn’t been defined yet, so it’s clear that this line hasn’t been executed yet. Use the next command to move on in the code:

(rdb:1) next
@@ -872,12 +858,12 @@ Loading development environment (Rails 2.1.0)
 @comments = []
 @recent_comments = []
-

Now you can see that the @comments relationship was loaded and @recent_comments defined because the line was executed.

-

If you want to go deeper into the stack trace you can move single steps, through your calling methods and into Rails code. This is one of the best ways to find bugs in your code, or perhaps in Ruby or Rails.

+

Now you can see that the @comments relationship was loaded and @recent_comments defined because the line was executed.

+

If you want to go deeper into the stack trace you can move single steps, through your calling methods and into Rails code. This is one of the best ways to find bugs in your code, or perhaps in Ruby or Rails.

3.7. Breakpoints

-

A breakpoint makes your application stop whenever a certain point in the program is reached. The debugger shell is invoked in that line.

-

You can add breakpoints dynamically with the command break (or just b). There are 3 possible ways of adding breakpoints manually:

-
    +

    A breakpoint makes your application stop whenever a certain point in the program is reached. The debugger shell is invoked in that line.

    +

    You can add breakpoints dynamically with the command break (or just b). There are 3 possible ways of adding breakpoints manually:

    +

    • break line: set breakpoint in the line in the current source file. @@ -890,7 +876,7 @@ Loading development environment (Rails 2.1.0)

    • -break class(.|#)method [if expression]: set breakpoint in method (. and # for class and instance method respectively) defined in class. The expression works the same way as with file:line. +break class(.|#)method [if expression]: set breakpoint in method (. and \# for class and instance method respectively) defined in class. The expression works the same way as with file:line.

    @@ -899,22 +885,22 @@ Loading development environment (Rails 2.1.0) 
    (rdb:5) break 10
 Breakpoint 1 file /PathTo/project/vendor/rails/actionpack/lib/action_controller/filters.rb, line 10
-

Use info breakpoints n or info break n to list breakpoints. If you supply a number, it lists that breakpoint. Otherwise it lists all breakpoints.

+

Use info breakpoints n or info break n to list breakpoints. If you supply a number, it lists that breakpoint. Otherwise it lists all breakpoints.

(rdb:5) info breakpoints
 Num Enb What
   1 y   at filters.rb:10
-

To delete breakpoints: use the command delete n to remove the breakpoint number n. If no number is specified, it deletes all breakpoints that are currently active..

+

To delete breakpoints: use the command delete n to remove the breakpoint number n. If no number is specified, it deletes all breakpoints that are currently active..

(rdb:5) delete 1
 (rdb:5) info breakpoints
 No breakpoints.
-

You can also enable or disable breakpoints:

-
    +

    You can also enable or disable breakpoints:

    +

    • enable breakpoints: allow a list breakpoints or all of them if no list is specified, to stop your program. This is the default state when you create a breakpoint. @@ -927,11 +913,11 @@ No breakpoints.

    3.8. Catching Exceptions

    -

    The command catch exception-name (or just cat exception-name) can be used to intercept an exception of type exception-name when there would otherwise be is no handler for it.

    -

    To list all active catchpoints use catch.

    +

    The command catch exception-name (or just cat exception-name) can be used to intercept an exception of type exception-name when there would otherwise be is no handler for it.

    +

    To list all active catchpoints use catch.

    3.9. Resuming Execution

    -

    There are two ways to resume execution of an application that is stopped in the debugger:

    -
      +

      There are two ways to resume execution of an application that is stopped in the debugger:

      +

      • continue [line-specification] (or c): resume program execution, at the address where your script last stopped; any breakpoints set at that address are bypassed. The optional argument line-specification allows you to specify a line number to set a one-time breakpoint which is deleted when that breakpoint is reached. @@ -944,8 +930,8 @@ No breakpoints.

      3.10. Editing

      -

      Two commands allow you to open code from the debugger into an editor:

      -
        +

        Two commands allow you to open code from the debugger into an editor:

        +

        • edit [file:line]: edit file using the editor specified by the EDITOR environment variable. A specific line can also be given. @@ -958,11 +944,11 @@ No breakpoints.

        3.11. Quitting

        -

        To exit the debugger, use the quit command (abbreviated q), or its alias exit.

        -

        A simple quit tries to terminate all threads in effect. Therefore your server will be stopped and you will have to start it again.

        +

        To exit the debugger, use the quit command (abbreviated q), or its alias exit.

        +

        A simple quit tries to terminate all threads in effect. Therefore your server will be stopped and you will have to start it again.

        3.12. Settings

        -

        There are some settings that can be configured in ruby-debug to make it easier to debug your code. Here are a few of the available options:

        -
          +

          There are some settings that can be configured in ruby-debug to make it easier to debug your code. Here are a few of the available options:

          +

          • set reload: Reload source code when changed. @@ -984,7 +970,7 @@ No breakpoints.

          -

          You can see the full list by using help set. Use help set subcommand to learn about a particular set command.

          +

          You can see the full list by using help set. Use help set subcommand to learn about a particular set command.

          @@ -993,7 +979,7 @@ No breakpoints. You can include any number of these configuration lines inside a .rdebugrc file in your HOME directory. ruby-debug will read this file every time it is loaded. and configure itself accordingly.
          -

          Here's a good start for an .rdebugrc:

          +

          Here’s a good start for an .rdebugrc:

          set autolist
@@ -1003,37 +989,36 @@ set listsize 25

          4. Debugging Memory Leaks

          -

          A Ruby application (on Rails or not), can leak memory - either in the Ruby code or at the C code level.

          -

          In this section, you will learn how to find and fix such leaks by using Bleak House and Valgrind debugging tools.

          +

          A Ruby application (on Rails or not), can leak memory - either in the Ruby code or at the C code level.

          +

          In this section, you will learn how to find and fix such leaks by using Bleak House and Valgrind debugging tools.

          4.1. BleakHouse

          -

          BleakHouse is a library for finding memory leaks.

          -

          If a Ruby object does not go out of scope, the Ruby Garbage Collector won't sweep it since it is referenced somewhere. Leaks like this can grow slowly and your application will consume more and more memory, gradually affecting the overall system performance. This tool will help you find leaks on the Ruby heap.

          -

          To install it run:

          +

          BleakHouse is a library for finding memory leaks.

          +

          If a Ruby object does not go out of scope, the Ruby Garbage Collector won’t sweep it since it is referenced somewhere. Leaks like this can grow slowly and your application will consume more and more memory, gradually affecting the overall system performance. This tool will help you find leaks on the Ruby heap.

          +

          To install it run:

          sudo gem install bleak_house
          -

          Then setup you application for profiling. Then add the following at the bottom of config/environment.rb:

          +

          Then setup you application for profiling. Then add the following at the bottom of config/environment.rb:

          -
          require 'bleak_house' if ENV['BLEAK_HOUSE']
-
          -

          Start a server instance with BleakHouse integration:

          +
          require 'bleak_house' if ENV['BLEAK_HOUSE']
          +

          Start a server instance with BleakHouse integration:

          RAILS_ENV=production BLEAK_HOUSE=1 ruby-bleak-house ./script/server
          -

          Make sure to run a couple hundred requests to get better data samples, then press CTRL-C. The server will stop and Bleak House will produce a dumpfile in /tmp:

          +

          Make sure to run a couple hundred requests to get better data samples, then press CTRL-C. The server will stop and Bleak House will produce a dumpfile in /tmp:

          ** BleakHouse: working...
 ** BleakHouse: complete
 ** Bleakhouse: run 'bleak /tmp/bleak.5979.0.dump' to analyze.
          -

          To analyze it, just run the listed command. The top 20 leakiest lines will be listed:

          +

          To analyze it, just run the listed command. The top 20 leakiest lines will be listed:

            191691 total objects
@@ -1049,17 +1034,17 @@ http://www.gnu.org/software/src-highlite -->
    834 /opt/local//lib/ruby/site_ruby/1.8/rubygems/version.rb:146:Array
   ...
          -

          This way you can find where your application is leaking memory and fix it.

          -

          If BleakHouse doesn't report any heap growth but you still have memory growth, you might have a broken C extension, or real leak in the interpreter. In that case, try using Valgrind to investigate further.

          +

          This way you can find where your application is leaking memory and fix it.

          +

          If BleakHouse doesn’t report any heap growth but you still have memory growth, you might have a broken C extension, or real leak in the interpreter. In that case, try using Valgrind to investigate further.

          4.2. Valgrind

          -

          Valgrind is a Linux-only application for detecting C-based memory leaks and race conditions.

          -

          There are Valgrind tools that can automatically detect many memory management and threading bugs, and profile your programs in detail. For example, a C extension in the interpreter calls malloc() but is doesn't properly call free(), this memory won't be available until the app terminates.

          -

          For further information on how to install Valgrind and use with Ruby, refer to Valgrind and Ruby by Evan Weaver.

          +

          Valgrind is a Linux-only application for detecting C-based memory leaks and race conditions.

          +

          There are Valgrind tools that can automatically detect many memory management and threading bugs, and profile your programs in detail. For example, a C extension in the interpreter calls malloc() but is doesn’t properly call free(), this memory won’t be available until the app terminates.

          +

          For further information on how to install Valgrind and use with Ruby, refer to Valgrind and Ruby by Evan Weaver.

        5. Plugins for Debugging

        -

        There are some Rails plugins to help you to find errors and debug your application. Here is a list of useful plugins for debugging:

        -