Overview

The library provides several built-in checks that you can use to monitor the health of your application. Each check implements the Check interface and can be added to the healthcheck service.

Built-in Checks

This library provides the following built-in checks:

• HTTP Check - Checks that a specific http endpoint is reachable and returns the expected status code.
• TCP Check - Checks that a TCP connection can be established to a specific host and port.
• Disk Check - Checks that a disk has enough free space.
• Memory Check - Checks that the system has enough free memory.
• Database Check - Checks that a database is reachable.
• Redis Check - Checks that a Redis instance is reachable.
• Mock Check - A mock check that returns the status passed to it. Useful for testing.

More checks may be added in the future. Pull requests are welcome!

Adding your own check

To add your own check, the only requirement is to implement the Check interface, which requires a single method Check(ctx context.Context) CheckResult.

Here is an example of a custom check that verifies if a specific file exists on the filesystem:

package main

import (
    "context"
    "os"
    "time"

    "github.com/brpaz/go-healthcheck/v2"
)

type FileExistsCheck struct {
    Name     string
    FilePath string
}

func (c *FileExistsCheck) Check(ctx context.Context) healthcheck.CheckResult {
    start := time.Now()
    _, err := os.Stat(c.FilePath)
    duration := time.Since(start).Milliseconds()

    if os.IsNotExist(err) {
        return healthcheck.CheckResult{
            Name:         c.Name,
            Status:       "fail",
            ComponentType: "file",
            Time:          time.Now().UTC(),
        }
    } else if err != nil {
        return healthcheck.CheckResult{
            Name:         c.Name,
            Status:       "fail",
            ComponentType: "file",
            Time:          time.Now().UTC(),
        }
    }

    return healthcheck.CheckResult{
        Name:         c.Name,
        Status:       "pass",
        ComponentType: "file",
        Time:          time.Now().UTC(),
    }
}

Note that each check can have multiple sub checks. This is useful when you want to group related checks together. For example, a database check can have sub checks for connection, and specific queries.