Master the time.Tick function in Go language documentation to implement interval timer

Go language is a powerful and flexible programming language. It has a rich standard library and documentation, and provides many practical functions and tools. Among them, the time.Tick function is a very useful function in the Go language. It can help us implement the function of executing certain codes within a certain time interval, that is, an interval timer.

This article will introduce how to master the time.Tick function in the Go language document and give specific code examples.

1. What is the time.Tick function?

The time.Tick function is a function in the Go language standard library. Its function is to return a channel (Channel). Through this channel, the program can receive a value every once in a while. This value is not important. What we are more concerned about is the occurrence time of this value, that is, the interval of the timer.

The function signature of time.Tick is:

func Tick(d Duration) <-chan Time

where d is the time interval, the type is Duration (time interval type), <-chan Time means that the function returns a read-only Time type aisle.

2. How to use time.Tick function?

It is very simple to implement an interval timer using the time.Tick function. We only need to use a for-range loop in the function and read the read-only channel returned by time.Tick. Specific examples are as follows:

package main

import (
    "fmt"
    "time"
)

func main() {
    ticker := time.Tick(1 * time.Second)
    for now := range ticker {
        fmt.Printf("%v
", now)
    }
}

In the above code, we use the time.Tick function to create a timer that triggers every 1 second. In the for loop, we use range to traverse the read-only channel returned by time.Tick, and each loop will output the value of the current time now.

Run the above code, we can see that the console outputs the current time every second:

2022-02-22 19:20:00.047375 +0800 CST m=+1.000141400
2022-02-22 19:20:01.047281 +0800 CST m=+2.000042824
2022-02-22 19:20:02.047335 +0800 CST m=+3.000095875
2022-02-22 19:20:03.047356 +0800 CST m=+4.000116659
...

In addition to outputting the current time, we can also perform some other operations in the loop body. For example, assuming we need to get data from the database every 3 seconds, we can add the corresponding code in the loop body:

package main

import (
    "database/sql"
    "fmt"
    "time"

    _ "github.com/go-sql-driver/mysql"
)

func main() {
    db, err := sql.Open("mysql", "root:password@tcp(127.0.0.1:3306)/database")
    if err != nil {
        fmt.Printf("open database failed: %v
", err)
        return
    }
    defer db.Close()

    ticker := time.Tick(3 * time.Second)
    for now := range ticker {
        fmt.Printf("%v
", now)

        rows, err := db.Query("SELECT * FROM user")
        if err != nil {
            fmt.Printf("query failed: %v
", err)
            continue
        }
        defer rows.Close()

        for rows.Next() {
            // do something with rows
        }
    }
}

In the above code, in each loop, we first output the current time now value, and then retrieve all the data in the user table from the database. Since the loop is triggered every 3 seconds, we can refresh the data from the database every 3 seconds.

3. Precautions for time.Tick function

Although the time.Tick function is simple and easy to use, you need to pay attention to the following points:

• time.Tick The parameter cannot be 0 or negative, otherwise it will cause an infinite loop.
• The timer created by time.Tick will keep running unless the program exits or the channel is closed.
• The channel (Channel) returned by the time.Tick function is read-only and data cannot be written, otherwise it will cause a compilation error.
• The timer created by time.Tick may conflict with other timers in the program, so you need to pay attention to the logical design of the code.

4. Summary

This article introduces the time.Tick function commonly used in the Go language standard library, and shows how to use this function to implement an interval timer through code examples. In practical applications, we can make corresponding modifications and extensions as needed, such as increasing the number of scheduled triggers, modifying the time interval, modifying the output content, etc.

The use of Time.Tick function can greatly help us simplify the code and improve the readability and ease of use of the program. It is one of the skills that every Go language programmer must master.

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