A Promise is an object representing the eventual completion or failure of an asynchronous operation. A JavaScript Promise object contains both the producing code and calls to the consuming code. It can be used to deal with Asynchronous operations in JavaScript.

Promise State:-

Pending – Initial State, Not yet Fulfilled or Rejected
Fulfilled/Resolved – Promise Completed
Rejected – Promise Failed

How Promise works

• A pending promise can either be Resolved with a value or Rejected with a reason (error).
• When either of these options happens, the associated handlers queued up by a promise’s then method are called.
• A promise is said to be settled if it is either Resolved or Rejected, but not Pending.

Creating Promise

Promise () – A Promise object is created using the new keyword and its constructor. This constructor takes a function, called the “executor function”, as its parameter. This function should take two functions as parameters. The first of these functions (resolve) is called when the asynchronous task completes successfully and returns the results of the task as a value. The second (reject) is called when the task fails and returns the reason for failure, which is typically an error object.

Syntax:- Promise (executor)

A JavaScript Promise object contains both the producing code and calls to the consuming code.

Function Returning a Promise

then( ) Method

The then() method returns a Promise. It takes up to two arguments: callback functions for the success and failure cases of the Promise. As then the method returns a Promise so we can do method chaining.

Syntax:- then(onResolved, onRejected)

onResolved – A Function called if the Promise is fulfilled. This function has one argument, the fulfillment value.

onRejected – A Function called if the Promise is rejected. This function has one argument, the rejection reason.

Promise

Chaining

The then method returns a Promise which allows for method chaining. If the function passed as a handler to then returns a Promise, an equivalent Promise will be exposed to the subsequent then in the method chain.

catch () Method

The catch() method returns a Promise and deals with rejected cases only. It behaves the same as calling then(undefined, onRejected). In fact, calling catch(onRejected) internally calls then(undefined, onRejected).

The catch method is used for error handling in promise composition. Since it returns a Promise, it can be chained in the same way as its sister method, then()

Syntax:- catch(callback)

Where the callback is a function called when the Promise is rejected. This function has one argument error – The rejection error.

catch () Method

finally () Method

The finally() method returns a Promise. When the promise is settled, i.e either fulfilled or rejected, the specified callback function is executed. This provides a way for code to be run whether the promise was fulfilled successfully or rejected once the Promise has been dealt with.

This helps to avoid duplicating code in both the promise’s then() and catch() handlers.

Syntax:- finally(callback)

finally () Method

Chaining

The post How does the JavaScript Promise work? appeared first on scmGalaxy.

JavaScript provides various ways of accessing form:-

• document.forms[index_number] – It returns collection of form in the documents.

• document.forms[“name_attribute_value”] – we can use name attribute of the form.

• document.name_attribute_value – we can use name attribute of the form with dot as well.

• getElementById(“ID”) – If form as an unique id we can use it.

Accessing Form Fields

If form fields have unique ID then it is possible to access them using the getElementById( ) method. However, There are some other ways: –

• elements[ ] – It contains collection of form fields.

Syntax: –

document.form_name.elements[index_number];
document.form_name.elements[“name_attribute_value”];
document.form_name.name_attribute_value;
document.form_name.ID_attribute_value;

• getElementsByName(“field_name”) – This method is also used to access form field.

The post Accessing Form Fields in JavaScript appeared first on scmGalaxy.

JavaScript provides access to the forms within an HTML document through the Form object known as HTMLFormElement in the DOM. Which is a child of the Document Object.

Properties

Properties

Methods

Events: –

• onreset
• onsubmit

The post How to use Form Handling in javascript appeared first on scmGalaxy.

The setTimeout() method sets a timer which executes a function or specified piece of code once after the timer expires. The function is only executed once. It returns a positive integer value which identifies the timer created by the call to setTimeout(); this value can be passed to clearTimeout() to cancel the timeout.

Syntax: –
setTimeout (function, milliseconds, para1, para2);
Ex: – var timeoutID = setTimeout(show, 2000);

clearTimeout( ) Method

The clearTimeout() method cancels a timeout previously established by calling setTimeout(). The ID value returned by setTimeout() is used as the parameter for the clearTimeout() method.

Syntax: – clearTimeout (timeoutID);

Ex: – clearTimeout(timeoutID);

setInterval( ) Method

The setInterval() method repeatedly calls a function or executes a code snippet, with a fixed time delay between each call. It returns an interval ID that uniquely identifies the interval, so you can remove it later by calling clearInterval().

Syntax: – setInterval (function, milliseconds, para1, para2);

Ex: – var intervalID = setInterval(show, 2000);

clearInterval( ) Method

The clearInterval() method cancels a timed, repeating action that was previously established by a call to setInterval().

Syntax: – clearInterval (intervalID);

Ex: – clearInterval(intervalID);

The post What is the difference between a timeout and an interval in Javascript? appeared first on scmGalaxy.

moveBy ( ) – This method moves the current window by a specified amount of pixels.

Syntax:- window.moveBy(horizontalPixels, verticalPixels);

Where,

window – It is the name of the window to move or is called just window if it is the main window.

horizontalPixels – It is the number of horizontal pixels to move the window where positive numbers move the window to the right and negative numbers to the left.

verticalPixels – It is the number of vertical pixels to move the window where positive number move the window down and negative number up.

Ex:- newWindow.moveBy(200, 200);

Moving Windows

moveTo ( ) – This method moves the window to the specified coordinates.

Syntax:- window.moveTo(x, y);

Where,

window – It is the name of the window to move or is called just window if it is the main window.

x – It is the screen co-ordinate on the x-axis to move the window to.

y – It is the screen co-ordinate on the y-axis to move the window to.

Ex:- newWindow.moveTo(200, 200);

Resizing Windows

Resizing Windows

resizeBy ( ) – This method is used to resize the current window by a certain amount, relative to its current size. 

Syntax:- window.resizeBy(width, height);

Where,

window – It is the name of the window to move or is called just window if it is the main window.

width – It is the number of width pixels, where positive numbers increase the window and negative numbers decrease.

height – It is the number of height pixels, where positive numbers increase the window and negative numbers decrease.

Ex:- newWindow.resizeBy(200, 200);

Resizing Windows

resizeTo ( ) – This method is used to resize a window to the specified width and height.

Syntax:- window.resizeTo(width, height);

Where,

window – It is the name of the window to move or is called just window if it is the main window.

width – It is an integer representing the new outerWidth in pixels (including scroll bars, title bars, etc).

height – It is an integer value representing the new outerHeight in pixels (including scroll bars, title bars, etc).

Ex:- newWindow.resizeTo(200, 200);

Scrolling Windows

scrollBy ( ) – This method scrolls the document in the window by the given amount.

Syntax:- window.scrollBy(x, y); or window.scrollBy(options);

Where,

window – It is the name of the window to scroll or is called just window if it is the main window.

x – How many pixels to scroll by, along the x-axis (horizontal). Positive values will scroll to the right, while negative values will scroll to the left

y – How many pixels to scroll by, along the y-axis (vertical). Positive values will scroll down, while negative values scroll up

Options – It is an object with three possible properties:
top, which is the same as the y-coord
left, which is the same as the x-coord
behavior, which is a string containing one of smooth, instant, or auto; default is auto

Note – For this method to work, the visible property of the window’s scrollbar must be set to true!

Scrolling Windows

scrollTo ( ) – This method scrolls to a particular set of coordinates in the document.

Syntax:- window.scrollTo(x, y); or window.scrollTo(options);

Where,

window – It is the name of the window to scroll or is called just window if it is the main window.

x – It is the pixel along the horizontal axis of the document that you want to be displayed in the upper left.

y – It is the pixel along the vertical axis of the document that you want to be displayed in the upper left.

options is an object with three possible properties:
top, which is the same as the y-coord
left, which is the same as the x-coord
behavior, which is a string containing either smooth, instant, or auto; default is auto

The post Moving Windows in JavaScript appeared first on scmGalaxy.

• Window object represents the browser’s window or potentially frame, that a document is displayed in.
• As long as a browser window is open, even if no document is loaded in the window, the window object is defined in the current model in memory.
• All global JavaScript variables, functions and objects automatically become members of the window object.

Dialog boxes

It is used to provide some information to users.

Type of Dialog box:-

• Alert
• Confirm
• Prompt

alert ( ) Method

This Window object’s method is used to display data in the alert dialog box. alert really should be used only when you truly want to stop everything and let the user know something.

Syntax:- window.alert( ) or alert ( )

confirm ( ) Method

This Window object’s method is used to display a message for a user to respond to by pressing either an OK button to agree with the message to a Cancel button to disagree with the message. It returns true on OK and false on Cancel.

Syntax:- window.confirm( ) or confirm ( )

prompt ( ) Method

Window object’s method prompt() can be used to get input from the user, named prompt. The prompt( ) method displays a dialog box that prompts the visitor for input.

Once the prompt function obtains input from the user, it returns that input. If the user press the cancel button in the dialog or close box, a value null will be returned.

Syntax: – prompt(text, defaultText)

open ( ) Method

The open( ) method creates a new secondary browser window, similar to choosing New Window from the File menu. It returns a Window object representing the newly-created window. If the window couldn’t be opened, the returned value is instead null.

Syntax: – window.open (URL, name, features, replace)

URL – URL indicates the document to load into the window. If no URL is specified, a new window with about: blank is opened

Name – Specifies the target attribute or the name of the window. The following values are supported:

_blank – URL is loaded into a new window. This is default
_parent – URL is loaded into the parent frame
_self – URL replaces the current page
_top – URL replaces any framesets that may be loaded

open ( ) Method

Syntax: – window.open (URL, name, features, replace)

Features – It is a comma-delimited string that lists the features of the window.

Replace – It indicates whether or not the URL specified should replace the window’s contents. This would apply to a window that was already created. Value can be true/false.

Features

Features

Features

close ( ) Method

Once a window is open, the close ( ) method is used to close it. It closes the current window or the window on which it was called. This method is only allowed to be called for windows that were opened by a script using the window.open() method. It is often used together with open ( ) method.

Syntax: – window.close ( )

The post What is a window object in JavaScript? What are its properties? appeared first on scmGalaxy.

The attributes property returns a live collection of all attribute nodes registered to the specified node. It is a read-only property.

Syntax:-
Element.attributes[index/key]

Attr Object

Properties

• name (do not use nodeName)
• value (do not use nodeValue or textContent or appendChild() or insertBefore( ) or removeChild( ) or replaceChild( ) these all are deprecated for attr object)

Methods

• setAttribute( )
• getAttribute( )
• removeAttribute( )

setAttribute( )

This method is used to set the value of an attribute on the specified element. If the attribute already exists, the value is updated; otherwise, a new attribute is added with the specified name and value. We should not use this method to set inline style as it will overwrite other CSS properties.

Syntax:-
Element.setAttribute(name, value);
Element.setAttribute(“style”, “css properties: value”);

Ex: –
p.setAttribute(“id”, “mydiv”);
p.setAttribute(“style”, “font-size: 80px”);

getAttribute( )

The getAttribute() returns the value of a specified attribute on the element. If the given attribute does not exist, the value returned will either be null or “ ”.

Syntax: –
var attribute = element.getAttribute(attributeName);

removeAttribute( )

This method is used to remove an attribute from the specified element.

Syntax: –
element.removeAttribute(attrName);

hasAttribute( )

The hasAttribute() method returns a Boolean value indicating whether the specified element has the specified attribute or not.

Syntax:-
var result = element.hasAttribute(attr_name);

The post Manipulation Attributes in JavaScript appeared first on scmGalaxy.

If referenceNode is null, the newNode is inserted at the end of the list of child nodes.

Syntax: –

parentNode.insertBefore(newNode, referenceNode);

insertAdjacentElement ( ) Method

The insertAdjacentElement() method inserts the specified element into a given specified position. It returns the element that was inserted, or null if the insertion failed.

Syntax:-

element – The element to be inserted into the tree.
The beforebegin and afterend positions work only if the node is in a tree and has an element parent.

insertAdjacentHTML ( ) Method

The insertAdjacentHTML() method is used to insert a text as HTML (parses the specified text as HTML or XML) into a specified position.

Syntax:-

text – The string to be parsed as HTML or XML and inserted into the tree.
It is recommended you not use insertAdjacentHTML when inserting plain text instead, use the node.textContent property

insertAdjacentText ( ) Method

The insertAdjacentText() method inserts the specified element into a specified position.

Syntax:-

text – The text which is about to insert.
The beforebegin and afterend positions work only if the node is in a tree and has an element parent.

The post Insert( ) Method in JavaScript appeared first on scmGalaxy.

• createElement(element_name)
• createTextNode(string)
• createComment(string)
• createDocumentFragment( )

Create Element Node

The createElement(element_name) method is used to create the HTML element specified by tagName, or an HTMLUnknownElement if tagName isn’t recognized. It returns the New Element.

Syntax:-
createElement(element_name)

Create Text Node

The createTextNode(string) method is used to create the Text Node with the specified text (string).

Syntax:-
createTextNode(string)

Create Comment Node

The createComment(string) method is used to create the Comment Node with the specified string and returns it.

Syntax:-
createComment (string)

Document Fragment

• The DocumentFragment interface represents a minimal document object that has no parent.
• A common use for Document Fragment is to create one, assemble a DOM subtree within it, then append or insert the fragment into the DOM using Node interface methods such as appendChild( ) or insertBefore( ).
• Document fragment isn’t part of the active document tree structure, changes made to the fragment don’t affect the document.
• Doing this moves the fragment’s nodes into the DOM, leaving behind an empty Document Fragment.
• An empty Document Fragment can be created using the document.createDocumentFragment() method.

Create Document Fragment

The createDocumentFragment() method creates a imaginary Node object, with all the properties and methods of the Node object.

The post How is Node.js created with JavaScript? appeared first on scmGalaxy.

The method querySelector() returns the first Element match of the specified selector or group of selectors. If no matches are found, null is returned.

querySelectorAll(“CSS Selector”)

The method querySelectorAll() returns a static (not live) NodeList representing a list of the document’s elements that match the specified group of selectors.

• The NodeList object represents a collection of nodes. The nodes can be accessed by index numbers. The index starts at 0.
• You can use the length property of the NodeList object to determine the number of elements that matches the specified selector, then you can loop through all elements and extract the info you want.
• If the specified selectors include a CSS pseudo-element, the returned list is always empty.

querySelectorAll(“CSS Selector”)

querySelectorAll(“CSS Selector”)

More specific

querySelectorAll(“CSS Selector”)

• Length Property

• Loop

innerHTML

The innerHTML property defines the HTML content.

The post How to Use CSS Selector in javascript? appeared first on scmGalaxy.

• Concat ( ) Method
• Join ( ) Method
• Reverse ( ) Method
• Slice( ) Method
• Splice ( ) Method
• toString( ) Method
• Array.isArray ( ) Method
• IndexOf ( ) Method
• Fill ( ) Method
• unshift ( ) Method
• Shift( ) Method
• Shift( ) Method
• pop( ) Method
• Map ( ) Method

Concat ( ) Method

The concat() method is used to merge two or more arrays. This method does not change
the existing arrays, but instead returns a new array.

Syntax:- new_array = old_array.concat(value1, value2, value_n);
Syntax:- new_array = old_array1.concat(old_array2, old_array_n);

Join ( ) Method

The join() method joins the elements of an array into a string, and returns the string. The elements will be separated by a specified separator. The default separator is the comma (,).

Syntax: – array_name.join(separator);

Reverse ( ) Method

The reverse() method reverses the order of the elements in an array.

Syntax :- array_name.reverse( );

Ex:- dev.reverse( );

Slice( ) Method

The slice( ) method returns a shallow copy of a portion of an array into a new array object selected from beginning to
end (end not included). The original array will not be modified.

Syntax: – array_name.slice(start, end)

Start
If begin is undefined, the slice begins from index 0.
If begin is greater than the length of the sequence, an empty array is returned.
A negative index can be used, indicating an offset from the end of the sequence. slice(-2) extracts the last two
elements in the sequence.

End
If end is omitted, slice extracts through the end of the sequence (arr.length).
If end is greater than the length of the sequence, slice extracts through to the end of the sequence (arr.length).
A negative index can be used, indicating an offset from the end of the sequence. slice(2,-1) extracts the third
element through the second-to-last element in the sequence.
slice extracts up to but not including end.

Splice ( ) Method

The splice() method changes the contents of an array by removing existing elements and/or adding new elements. This method changes the original array.

Syntax:- array_name.splice (start, deletecount, replacevalues);

Start – The first argument start specifies at what position to add/remove items, uses negative values to specify the position from the end of the array.

Deletecount – The second argument deletecount, is the number of elements to delete
beginning with index start.

Replacevalues – replacevalues are inserted in the place of the deleted elements. If more
than one separate it by a comma.

toString( ) Method

The toString ( ) method returns a string containing the comma-separated values of the array. This method is invoked automatically when you print an array. It is equivalent to invoking the join ( ) method without any arguments. The
the returned string will separate the elements in the array with commas.

Syntax: – array_name.toString();

Array.isArray ( ) Method

The Array.isArray() method determines whether the passed value is an Array. This function returns true if the object is an array, and false if not.

Syntax:- Array.isArray(value);

IndexOf ( ) Method

This method allows us to easily find the occurrence of an item in an array.

• If the item is not found, it returns -1.
• The search will start at the specified position, or at the beginning if no start position is specified, and end the search at the end of the array.
• If the item is present more than once, the indexOf method returns the position of the first occurrence.

Syntax: – var position = array_name.indexOf(item, start);

Ex:- var position = dev.indexOf(“Rohit”, 2);

Fill ( ) Method

The fill() method fills all the elements in an array with a static value.

Syntax:- array_name.fill(value, start, end)

unshift ( ) Method

The unshift() method adds one or more elements to the beginning of an array and returns the new length of the array.
This method changes the length of an array.

Syntax: –
Array_name.unshift(value1, value2, value_n);

Push ( ) Method

The push() method adds one or more elements to the end of an array and returns the new length of the array.
The new item will be added at the end of the array.
This method changes the length of the array.

Syntax: –
Array_name.push(value1, value2, value_n);

Shift( ) Method

The shift() method removes the first element from an array and returns that removed element. This method changes the length of the array.

Syntax: – array_name.shift( );

Ex: – geek.shift( );

pop( ) Method

The pop() method removes the last element from an array and returns that removed element. This method changes the length of the array.

Syntax: – array_name.pop( );

Ex: – geek.pop( );

Map ( ) Method

The map() method creates a new array with the results of calling a provided function on every element in the calling array.
The map() method calls the provided function once for each element in an array, in order.

map() does not execute the function for array elements without values.
map() does not change the original array.

Syntax:- array_name.map(function(currentValue, index, array)
{
}, thisValue

The post What’s the use of the method in JavaScript? appeared first on scmGalaxy.

Object Oriented Progrmming

Object-Oriented Programming is a Technic that solves the problem. In this, the code breaks the object. And you see your problem on the side of the object. In which you find your problem similar to the real-world problem and it is easy to maintain, and it has to be solved.

Class

The PHP class has a group of values. To manipulate whatever value you write inside the class, you also write operations in it. The class gives you this facility, that if the user does not need to know the information. So you can also hide the information. To use the application, you can keep it hidden for security purposes. Or if it will be accessed from the outside users or from an outside viewer then your application may be damaged. That’s why you can keep your application hidden, it gives class facility. You can define type using class.

Rule

• The class name can be any valid label.
• It can’t be PHP reserved world.
• The class name must start with a letter or an underscore. Following by any number of letters, numbers, or underscore all this will work. Lwkin should not start with number.

class Classname
{
	var $variable_name;  (It is also called Data Member/Properties or Attribute.)
	var $variable_name;
	
	function Method_name()
	{
		Body of method;
	}
	function Method_name(parameter_list)     (And these methods are called methods or member functions.)
	{
		Body of Method;
	}

}

See your problem in the real world.

class Mobile
{
	public $model;
	function show Model (Sumber)
	{
		$this->model = $number;
		echo "Model Number: $this->model";
	}
	
}

Object

The object is a variable of class data type. Whenever you create an object, for that object, whatever is proper inside the class, a copy of it is prepared and it is prepared for that object. If there are 2 objects then 2 copies of that variable or that property will be created and one copy for the first object and a second copy for the second object. Whatever object you make, its copy will be ready and one copy will be distributed. But this is not the case with the member function. The member function is the same, all the objects share with it.

The new Operator is used to create an object.

Syntax:

class Mobile
{
	public $model;
	function show Model (Sumber)
	{
		$this->model = $number;
		echo "Model Number: $this->model";
	}
	
}
$samsung = new Mobile;
$samsung->showModel('A5');

$lg = new Mobile;
$lg->showModel('M30');

You will not need to write the class, again and again, you just have to create an object of it. And call this method with the help of that object. It will show its own model number.

Important thing

A class is of no importance unless it has an object.

Accessing class member using object

How would you make accessing a member of a class into a user object?

-> This operator is used to access the member of the class.

object_name->variable_name;
$samsung->model;

access to method
Object_name->method_name();
$samsung->showModel();

in parameter
Object_name->method_name(parameter_list)
$samsung->showModel(‘A8’);

The post Advance PHP appeared first on scmGalaxy.

When I am trying to put some value in my input search box and after pressing enter button showing above issue.
But when I am trying to filter data with my search button then it’s working fine. so i dig into it. i found one solution on it.

FilterController.php

$users = DB::table('users')
->where(function($query) use ($countryId, $stateId, $cityId) {
	if (isset($countryId) && $countryId !== null && $countryId !== '' && $stateId == 'Select State') {
		$query->where('country_id', '=', $countryId);
	}
	if (isset($countryId) && $countryId !== null && $countryId !== '' && isset($stateId) && $stateId !== 'Select State' && $stateId !== '') {
		$query->where([
							['country_id', '=', $countryId],
							['state_id', '<>', $stateId]
						]);
		
	}
})->get()->paginate(5);

Solution :

Just remove the get() and your code will work fine.

$users = DB::table('users')
->where(function($query) use ($countryId, $stateId, $cityId) {
	if (isset($countryId) && $countryId !== null && $countryId !== '' && $stateId == 'Select State') {
		$query->where('country_id', '=', $countryId);
	}
	if (isset($countryId) && $countryId !== null && $countryId !== '' && isset($stateId) && $stateId !== 'Select State' && $stateId !== '') {
		$query->where([
							['country_id', '=', $countryId],
							['state_id', '<>', $stateId]
						]);
		
	}
})->paginate(5);

References :

1. Click here
2. Click here

The post Laravel 5.5 Method paginate does not exist appeared first on scmGalaxy.

The tasks can be scheduled to run on the same machine (Master), or on a different machine (Slave). A master is a installation of Hudson, that can manage one or more slaves. The role of master remains same in Master slave setup. It serves HTTP requests, and it can still build projects on it’s own.

Slaves are computers that are setup to build projects triggered from the master. A separate program called slave agent runs on slave computer. In this article we’ll discuss about how to setup Hudson to executed distributed builds using Master slave. One computer can be configured to execute multiple slave agents.

How it works

When the slaves are registered to a master, the master starts distributing loads to slaves. The delegation depends on the specific job. The job can be configured to either execute on the master, or it can be tied to a specific slave. On the other hand, the jobs can be configured to freely roam between slaves, wherein the job is executed using the free slave. As per the user is concerned, the setup is transparent. The results for all jobs are viewable using the Master, irrespective of the Slave that executed the job.

The slave may be built using any Operating system. The Master slave setup is highly helpful while the user has to execute the job on different Operating system. Consider this use case: The application is expected to run on different operating system, Linux, Solaris and Windows system. To address this need, the user can install Hudson on any machine, say Linux, and add 2 slaves: Solaris and Windows. The user can add 3 different jobs, one running on Master itself and others running on slave machines.

Methods to set up Slave agents

The slave can be launched from Master using any of below methods:

1. Launch Slave agents on Unix machines via SSH.
2. Launch Slave agents via JNLP.
3. Launch Slave agents via execution of command on the master.
4. Let Hudson control windows slave as a windows service.

The following screenshot illustrates the list of modes under which the Hudson slave can be launched.

Set up Slave agents on Unix machines via SSH

Hudson has a built-in SSH client implementation that it can use to talk to remote sshd and start a slave agent. This is the most convenient and preferred method for Unix slaves, which normally has sshd out-of-the-box. Click Manage Hudson, then Manage Nodes, then click New Node. In this set up, the connection information is supplied, including SSH host name, user name and authentication credentials. The authentication is performed using password or ssh keys. If it is configured to use ssh keys, the SSH public key should be copied to ~/.ssh/authorized_keys file. Hudson will do the rest of the work by itself, including copying the binary needed for a slave agent, and starting/stopping slaves.

 

Depending on the project and hardware resource availability, the user Desktop can be used as one of Slave, without affecting his day-to-day activities, thus avoiding the need for dedicated Slaves.

Establish slave agent via Java Web Start

Another way of launching slave is to start a slave agent through Java Web Start (JNLP). In this approach, the user will login to the slave node, open a browser and open the slave page using the URL pointed to the Master. It may look like the following URL:

http://masterserver:port/hudson/jnlpJars/slave.jar

The user is presented with the JNLP launch icon. If user click the icon, the Java Web Start kicks in and it launches a slave agent on this computer.

This mode is convenient when the master cannot initiate a connection to slaves, such as when it runs outside a firewall while the rest of the slaves are in the firewall. The disadvantage is, if the machine with a slave agent goes down, the master has no way of re-launching it on its own.

Set up slave agent headlessly

This launch mode uses a mechanism very similar to Java Web Start, except that it runs without using GUI, making it convenient for an execution as a daemon on Unix. To do this, the user should configure this slave to be a JNLP slave by downloading slave.jar, and then from the slave, run a command like this:

java -jar slave.jar -jnlpUrl http://yourserver:port/computer/slave-name/slave-agent.jnlp

The slave.jar file is downloaded from the above mentioned URL. Make sure to replace slave-name with the name of the slave setup in Master.

By default, Hudson runs on port 8080. It can be installed and managed without the need for super user privilege. The super user privilege is not required to manage both Master and Slave.

The below diagram illustrates the list of configuration parameters specific to a slave.

 

set up Slave Agent using own scripts

If the above modes is not flexible, the user can write his own script to launch the Slave agent. The script is placed in the Master computer and Hudson runs this script whenever it should connect to the slave. The script may use the remote login program like SSH, RSH to establish connection between Master and slave.

The script would execute the slave agent program like java -jar slave.jar. The stdin and stdout for the script should be connected to the master. For example, the script that does ssh myslave java -jar ~/bin/slave.jar would satisfy this need, when it is executed from the Master web interface. For this reason, running this script manually from the command line does no good.

The copy of slave.jar can be downloaded from the above mentioned URL. Launching the slave agent using this mode requires additional setup in the Slave. The benefit is that when the connection goes bad, the user can use Hudson web interface to re-establish the connection.

The post How to Setup Configure Hudson Master Slave? – Complete Guide appeared first on scmGalaxy.

How to put comment in Ant | Comments in Apache Ant

Method 1:

<!– Comments are just as important in buildfiles, do not –>
<!– avoid writing them! –>
<!– Example build file for “Ant: The Definitive Guide” –>
<!– and its sample project: irssibot –>

Method 2: Echo
Description
Writes a message to the Ant logging facilities. A message may be supplied
as nested text to this task.
Echoes a message to the current loggers and listeners which means System.out unless overridden. A level can be specified, which controls at what logging level the message is filtered at.
The task can also echo to a file, in which case the option to append rather than overwrite the file is available, and the level option is ignored

Parameters

Examples
Style 1:
<echo message=”Hello, world”/>

Style 2:
<echo message=”Embed a line break:${line.separator}”/>

Style 3:
<echo>Embed another:${line.separator}</echo>

Style 4:
<echo>This is a longer message stretching over
two lines.
</echo>

Style 5:
<echo>
This is a longer message stretching over
three lines; the first line is a blank
</echo>

Style 5:
<echo message=”Deleting drive C:” level=”debug”/>
A message which only appears in -debug mode.

Style 6:
<echo level=”error”>
Imminent failure in the antimatter containment facility.
Please withdraw to safe location at least 50km away.
</echo>
A message which appears even in -quiet mode.

Style 7:
<echo file=”runner.csh” append=”false”>#\!/bin/tcsh
java-1.3.1 -mx1024m ${project.entrypoint} $$*
</echo>
Generate a shell script by echoing to a file. Note the use of a double $ symbol to stop Ant filtering out the single $ during variable expansion
Depending on the loglevel Ant runs, messages are print out or silently ignored:

Method 3:
Description

The post How to put comment in Ant | Comments in Apache Ant appeared first on scmGalaxy.

Situation

1. For one of our clients, Build is taking 8 hours and nightly build is failing frequently.
2. Test case execution is consuming more time than the compilation.
3. Low confidence levels for developers on nightly builds and subsequently during integration cycle.

Approach

1. We reviewed the whole set of build scripts being used and test case suite to check how we can refatcor them.
2. Verified the build infrastructure i.e., build server capacity from hardware point of view.
3. Feasibility study done to check how a CI environment help in giving faster feedback on the quality.

Solution

1. Refactoring done for build scripts to make modules compilation parallel (wherever possible).
2. Some test cases are selected (which don’t require external services like database) to run as part of the build.
3. CI environment (using open source cruise control) is established to run builds per commit and execute only above set of test cases as part of the build.
4. Set up low-cost remote agent machine which will run remaining test suite once per day.

Results

1. Build took only 1 hour and gave faster feedback to dev team.
2. CI environment provided good confidence to dev team.
3. Team is able to implement more best practices.
4. Effective use of existing build  infrastructure (hardware) ensured no further cost is required.
5. This helped the client in ensuring smooth release management.

The post How we reduced build time from 8 hours to 1 hour ? – Complete Guide appeared first on scmGalaxy.