Tutorial by Examples: d

Modal views completely capture the user’s attention until a task is complete. iOS clarifies this to users by dimming and disabling all other content when a modal view, such as an alert or popover, is visible. An app that implements a custom modal interface needs to hint to VoiceOver that this view d...

Most UIKit classes, including UIView, adhere to UIAccessibilityProtocol and return correct values by default. It’s easy to take for granted that a UIView set to hidden is also absent from the accessibility hierarchy and won’t be navigated by VoiceOver. While this default behavior is usually sufficie...

1.8 You can remove a submodule (e.g. the_submodule) by calling: $ git submodule deinit the_submodule $ git rm the_submodule git submodule deinit the_submodule deletes the_submodules' entry from .git/config. This excludes the_submodule from git submodule update, git submodule sync and git ...

IDLE is Python’s Integrated Development and Learning Environment and is an alternative to the command line. As the name may imply, IDLE is very useful for developing new code or learning python. On Windows this comes with the Python interpreter, but in other operating systems you may need to install...

You can use a template in a function based view as follows: from django.shortcuts import render def view(request): return render(request, "template.html") If you want to use template variables, you can do so as follows: from django.shortcuts import render def view(request):...

List Comprehensions can use nested for loops. You can code any number of nested for loops within a list comprehension, and each for loop may have an optional associated if test. When doing so, the order of the for constructs is the same order as when writing a series of nested for statements. The ge...

Closures are often used for asynchronous tasks, for example when fetching data from a website. 3.0 func getData(urlString: String, callback: (result: NSData?) -> Void) { // Turn the URL string into an NSURLRequest. guard let url = NSURL(string: urlString) else { return } let re...

It is possible to force the type parameters of a generic class to implement a protocol, for example, Equatable class MyGenericClass<Type: Equatable>{ var value: Type init(value: Type){ self.value = value } func getValue() -> Type{ return self....

Scollector has built in support for using cAdvisor to generate container.* metrics in Bosun for each Docker container on a host. To get started you will need to start a new container on each docker host: docker run --name cadvisor --restart=always -d -p 8080:8080 google/cadvisor And then from an...

Example init script for scollector: #!/bin/bash # # scollector Startup script for scollector. # # chkconfig: 2345 90 60 # description: scollector is a replacement for OpenTSDB's TCollector \ # and can be used to send metrics to a Bosun server # Source function library. . /etc/init....

Here is an init.d script for Bosun that includes setting Environmental Variables that can be used to hide secrets from the raw config. It uses http://software.clapper.org/daemonize/ to run the program as a daemon. #!/bin/sh # # /etc/rc.d/init.d/bosun # bosun # # chkconfig: - 98 02 # descripti...

#Create Bosun unit file at /etc/systemd/system/bosun.service [Unit] Description=Bosun Service After=network.target After=rsyslog.service [Service] Type=simple User=root ExecStart=/opt/bosun/bosun -c /opt/bosun/config/prod.conf Restart=on-abort [Install] WantedBy=multi-user.target #...

#Create Scollector unit file at /etc/systemd/system/scollector.service [Unit] Description=Scollector Service After=network.target [Service] Type=simple User=root ExecStart=/opt/scollector/scollector -h mybosunserver.example.com Restart=on-abort [Install] WantedBy=multi-user.target #...

TSDBRelay can be used to forward metrics to an OpenTSDB instance, send to Bosun for indexing, and relay to another opentsdb compatible instance for backup/DR/HA. It also has options to denormalize metrics with high tag cardinality or create redis/ledis backed external counters. #Create tsdbrelay un...

Chef Scollector Cookbook: https://github.com/alexmbird/chef-scollector Chef Bosun Cookbook: https://github.com/ptqa/chef-bosun Puppet scollector module: https://github.com/axibase/axibase-puppet-modules Bosun Ansible/Vagrant example: https://github.com/gnosek/bosun-deploy

docker ps --filter name=myapp_1

This example assumes Ruby is installed. Place the following in a file named hello.rb: puts 'Hello World' From the command line, type the following command to execute the Ruby code from the source file: $ ruby hello.rb This should output: Hello World The output will be immediately di...

To explicitly declare variables in VBA, use the Dim statement, followed by the variable name and type. If a variable is used without being declared, or if no type is specified, it will be assigned the type Variant. Use the Option Explicit statement on first line of a module to force all variables t...

public class CustomFormat : IFormatProvider, ICustomFormatter { public string Format(string format, object arg, IFormatProvider formatProvider) { if (!this.Equals(formatProvider)) { return null; } if (format == "Reverse") ...

7 Object spreading is just syntactic sugar for Object.assign({}, obj1, ..., objn); It is done with the ... operator: let obj = { a: 1 }; let obj2 = { ...obj, b: 2, c: 3 }; console.log(obj2); // { a: 1, b: 2, c: 3 }; As Object.assign it does shallow merging, not deep merging. let obj3 = ...