Tutorial by Examples: e

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....

#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 --format 'table {{.ID}}\t{{.Names}}\t{{.Status}}'

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...

git bisect allows you to find which commit introduced a bug using a binary search. Start by bisecting a session by providing two commit references: a good commit before the bug, and a bad commit after the bug. Generally, the bad commit is HEAD. # start the git bisect session $ git bisect start ...

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") ...

Serialization with Gson is easy and will output correct JSON. public class Employe { private String firstName; private String lastName; private int age; private BigDecimal salary; private List<String> skills; //getters and setters } (Serialization) ...

div { font-size: 7px; border: 3px dotted pink; background-color: yellow; color: purple; } body.mystyle > div.myotherstyle { font-size: 11px; background-color: green; } #elmnt1 { font-size: 24px; border-color: red; } .mystyle .myotherstyle { ...

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 = ...

In order to create a new Android HTTP Client HttpURLConnection, call openConnection() on a URL instance. Since openConnection() returns a URLConnection, you need to explicitly cast the returned value. URL url = new URL("http://example.com"); HttpURLConnection connection = (HttpURLConnect...

URL url = new URL("http://example.com"); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); try { BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream())); // read the input stream // in this case, I simply read t...