golang pubsub

This article gives an example of how Golang determines whether Chan channel is closed. Share to everyone for your reference, specific as follows: A friend in the group asked how to tell if Chan was closed because the channel of close does not block and returns the nil value of the type, resulting in a dead loop. Write an example here to record and share If you don't judge whether Chan is closed Notice: The following code produces a dead loop

The Golang runtime (runtime) manages a lightweight thread called Goroutine. Creating a level hundreds of thousands of goroutine is no problem. Example: Copy Code code as follows: Package Main Import ( "FMT" "Time" ) Func say (s string) { For I: = 0; I Time. Sleep (* time.millisecond) Fmt. PRINTLN (s) } } Func Main () { Open a goroutine execute say function Go say (' World ') Say ("Hello") } We

problem and found an open CC project to do this. Then the Golang call The package on GitHub has also been implemented, it has been tried, and really good results. Example: Package main /* Use OPENCC for simple example OPENCC library: Https://github.com/BYVoid/OpenCC OPENCC wrapper for GOLANG:GITHUB.COM/STEVENYAO/GO-OPENCC author:xcl * /import ( "FMT" OPENCC "github.com/ STEVENYAO/GO-OPENCC " ) func main () { //Mac local config_s2

Golang 1.7 version of the context library is used by many standard library modules, such as net/http and OS modules, using these native modules, we do not need to write the context of the manager, directly call the function interface can be implemented, Using context, we can implement some variable management such as the request's declaration period, perform some operation timeouts and so on. Save Context Object Here we look at a simple example of how

Currently Golang the latest version is 1.9, generics are not supported for the time being. However, you can implement the "generic programming" effect via interface, as an example of adding/removing elements of the slice type data, for your reference: Package main import ("Errors" "FMT") var (err_elem_exists = errors. New ("element exits.") err_elem_not_exists = errors. New ("element not exits.")) Define slice, support interface{} type//As

() and Exec() finished INSERT , UPDATE , DELETE operation.Transactiondb.Begin()Start a transaction, Commit() or Rollback() close a transaction. TxRemove a connection from the connection pool and use this connection before closing. TX cannot be mixed with the DB layer BEGIN COMMIT .If you need to modify the connection state through multiple statements, you must use TX, for example: Create a temporary table that is visible only to a single connection Set variables, such asSET

The built-in function make is used to allocate memory for the Slice,map or Chan type and initialize an object (note: It can only be used on these three types), similar to new, the first parameter is a type instead of a value, unlike new, make returns the structure of the type rather than the pointer, and the return The return value also depends on the specific incoming type The code for the Make () function in Golang is as follows: Func make (t type,s

Because of the company arrangement, I temporarily moved from the Java project team to the Go Project team, after almost 5 days of spare time to go to study, the architect let me to the company colleagues Golang sharing and training.Colleagues were very passionate about technology, and were expected to share it for 40 minutes, which lasted 2 hours, thanks to the active discussion of colleagues and the enthusiastic addition of colleagues from the go big

Reference GOCN Sometimes you need to turn the backend HTTP service into HTTPS, and you can use a proxy. Reamark: If it is a Golang backend service, you can use the library Go-oryx-lib/https directly. This agent supports self-signed certificates and also supports Letsencrypt certificates. Remark:letsencrypt only support a small number of domain names, such as their own website, it will have the limit of the number of requests, the other CA is Letsencry

S: = Strings. Split ("", "") FMT. Println (S, Len (s)) s = strings. Split ("Abc,abc", "" ") FMT. Println (S, Len (s)) s = strings. Split ("", ",") FMT. Println (S, Len (s)) s = strings. Split ("Abc,abc", ",") FMT. Println (S, Len (s)) s = strings. Split ("Abc,abc", "|") Fmt. Println (S, Len (s)) FMT. Println (Len ("")) FMT. Println (Len ([]string{""})) str: = "" fmt. Println (Str[0]) Operation Result: [] 0//Return empty array[a b c, a B

The problem with Oracle SDK compilation is well solved under MacOS and Linux, because GCC and pkg-config are both self-bringing programs. However, there are no two programs under windows that need to be installed on your own. The advantage is that MSYS2 has encapsulated two programs, configured as follows: Install MSYS2 tutorial as follows, point me to view. After the installation is complete, use the Pacman-s Mingw-w64-x86_64-toolchain Note: The default for direct use of the pacman–s GCC inst

A systematic review of Golang knowledge, today summarizes some of the characteristics of the channel and some simple implementation.Don ' t communicate by sharing memory;share memory by communicating. 1, the channel type itself is concurrency-safe, which is the only type of go that can meet concurrency security.2, the channel needs to be initialized because it is a reference type, otherwise its value is nil, and any operation on it will be blocked.3,

{Countrystring' DB:"Country"' Citystring' DB:" City"' Telcodeint' DB:"Telcode"` } varDb *SQLX. DB func init () {database, err:= Sqlx. Open ("MySQL","[email protected] (127.0.0.1:3306)/test") ifErr! =Nil {fmt. Println ("Open MySQL failed,", Err)return} Db=Database} func Main () {_, Err:= Db.exec ("Update person set username=? where user_id=?","chaoge666",1) ifErr! =Nil {fmt. Println ("exec failed,", Err)} } UpdateDelete DeletePackage main Import ("FMT" _ "Github.com/go-sql-driver/mys

arrives.Setconnmaxlifetime ()If it is less than 0, it never expiresThe maximum life cycle for idle connections should be less than the time-out for database connections.When the connection is created or when the connection is pooled, the connection is timed out only in the connection pool.Conn ()Remove from the connection pool or create a connection to return. In the returned SQL. On the conn, the Ping,Exec,Query,QueryRow,Begin operation is on the current connection. Attention:Sql. The conn con

Label:Using go-sql-driver to manipulate MYQL databases package main import ("Database/sql" _ "github.com/ Go-sql-driver/mysql "" FMT ") func main () {//Connect database, get connection handle db, err: = SQL. Open ("MySQL", "root:[emailprotected" (localhost:3306)/huifang5?charset=utf8 ") if err! = Nil {panic (err. Error ())} defer db. Close ()//Execute SQL statement returns multiple rows of result set results, err: = db. Query ("select * from Hf_test where keshiid=?", 0) if err! = Nil {panic (er

21-day Boutique blockchain free learning, in-depth expert led the way, to help developers easily play the blockchain! >>> Golang pprof When your Golang program consumes more memory than you understand during the run, you need to figure out what code in the program is causing the memory consumption. At this time Golang compiled program for you is a black box,

Golang-proxyv2.0 Golang-proxy--Simple and efficient free agent crawler to maintain a high-stealth proxy pool for web crawlers, resource downloads and other uses by crawling free agents exposed on the network. Are you still writing proxy crawlers in Python? Try golang!. Available out-of-the-box version, without any programming basis to use What's new in V2.0?

This is a creation in Article, where the information may have evolved or changed. Golang's interface is a ghost. Problem overview Golang's interface is different from other languages. It does not require explicit implements, and as long as a struct implements all the functions in interface, the compiler automatically thinks it implements this interface. The first time I saw this design, my first reaction was: What's the fuck? What is the difference between the design of this wonderful flow

This is a creation in Article, where the information may have evolved or changed. The concurrency mechanism of the go language and the CSP concurrency model it uses CSP Concurrency modelThe CSP model was proposed in the 70 's to describe the concurrency model of two independent concurrent entities communicating via a shared communication channel (pipeline). Channel in CSP is the first class of objects that does not focus on the entity that sends the message, but on the channel used to send

other language-enabled proto plugins and Protobuf compilers. If you do not use these languages, you can just install PROTOBUF, reference project: Protobuf. Java and go support have standalone projects Grpc-java and grpc-go. Golang Protobuf Plug-in Project Address: Golang/protobuf Installation: Requires Golang version > 1.4 Require installation of the pr