Mailgun with Go

Go library for interacting with the Mailgun API.

Usage

package main

import (
    "context"
    "fmt"
    "log"
    "time"

    "github.com/mailgun/mailgun-go/v4"
)

// Your available domain names can be found here:
// (https://app.mailgun.com/app/domains)
var yourDomain string = "your-domain-name" // e.g. mg.yourcompany.com

// You can find the Private API Key in your Account Menu, under "Settings":
// (https://app.mailgun.com/app/account/security)
var privateAPIKey string = "your-private-key"


func main() {
    // Create an instance of the Mailgun Client
    mg := mailgun.NewMailgun(yourDomain, privateAPIKey)

    sender := "sender@example.com"
    subject := "Fancy subject!"
    body := "Hello from Mailgun Go!"
    recipient := "recipient@example.com"

    // The message object allows you to add attachments and Bcc recipients
    message := mg.NewMessage(sender, subject, body, recipient)

    ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
    defer cancel()

    // Send the message with a 10 second timeout
    resp, id, err := mg.Send(ctx, message)

    if err != nil {
        log.Fatal(err)
    }

    fmt.Printf("ID: %s Resp: %s\n", id, resp)
}

Get Events

package main

import (
    "context"
    "fmt"
    "time"

    "github.com/mailgun/mailgun-go/v4"
    "github.com/mailgun/mailgun-go/v4/events"
)

func main() {
    // You can find the Private API Key in your Account Menu, under "Settings":
    // (https://app.mailgun.com/app/account/security)
    mg := mailgun.NewMailgun("your-domain.com", "your-private-key")

    it := mg.ListEvents(&mailgun.ListEventOptions{Limit: 100})

    var page []mailgun.Event

    // The entire operation should not take longer than 30 seconds
    ctx, cancel := context.WithTimeout(context.Background(), time.Second*30)
    defer cancel()

    // For each page of 100 events
    for it.Next(ctx, &page) {
        for _, e := range page {
            // You can access some fields via the interface
            fmt.Printf("Event: '%s' TimeStamp: '%s'\n", e.GetName(), e.GetTimestamp())

            // and you can act upon each event by type
            switch event := e.(type) {
            case *events.Accepted:
                fmt.Printf("Accepted: auth: %t\n", event.Flags.IsAuthenticated)
            case *events.Delivered:
                fmt.Printf("Delivered transport: %s\n", event.Envelope.Transport)
            case *events.Failed:
                fmt.Printf("Failed reason: %s\n", event.Reason)
            case *events.Clicked:
                fmt.Printf("Clicked GeoLocation: %s\n", event.GeoLocation.Country)
            case *events.Opened:
                fmt.Printf("Opened GeoLocation: %s\n", event.GeoLocation.Country)
            case *events.Rejected:
                fmt.Printf("Rejected reason: %s\n", event.Reject.Reason)
            case *events.Stored:
                fmt.Printf("Stored URL: %s\n", event.Storage.URL)
            case *events.Unsubscribed:
                fmt.Printf("Unsubscribed client OS: %s\n", event.ClientInfo.ClientOS)
            }
        }
    }
}

Event Polling

The mailgun library has built-in support for polling the events api

package main

import (
    "context"
    "time"

    "github.com/mailgun/mailgun-go/v4"
)

func main() {
    // You can find the Private API Key in your Account Menu, under "Settings":
    // (https://app.mailgun.com/app/account/security)
    mg := mailgun.NewMailgun("your-domain.com", "your-private-key")

    begin := time.Now().Add(time.Second * -3)

    // Very short poll interval
    it := mg.PollEvents(&mailgun.ListEventOptions{
        // Only events with a timestamp after this date/time will be returned
        Begin: &begin,
        // How often we poll the api for new events
        PollInterval: time.Second * 30,
    })

    ctx, cancel := context.WithCancel(context.Background())
    defer cancel()

    // Poll until our email event arrives
    var page []mailgun.Event
    for it.Poll(ctx, &page) {
        for _, e := range page {
            // Do something with event
        }
    }
}

Email Validations

package main

import (
    "context"
    "fmt"
    "log"
    "time"

    "github.com/mailgun/mailgun-go/v4"
)

// If your plan does not include email validations but you have an account,
// use your Public Validation api key. If your plan does include email validations,
// use your Private API key. You can find both the Private and
// Public Validation API Keys in your Account Menu, under "Settings":
// (https://app.mailgun.com/app/account/security)
var apiKey string = "your-api-key"

func main() {
    // To use the /v4 version of validations define MG_URL in the envronment
    // as `https://api.mailgun.net/v4` or set `v.SetAPIBase("https://api.mailgun.net/v4")`

    // Create an instance of the Validator
    v := mailgun.NewEmailValidator(apiKey)

    ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
    defer cancel()

    email, err := v.ValidateEmail(ctx, "recipient@example.com", false)
    if err != nil {
        panic(err)
    }
    fmt.Printf("Valid: %t\n", email.IsValid)
}

Webhook Handling

package main

import (
    "context"
    "encoding/json"
    "fmt"
    "net/http"
    "os"
    "time"

    "github.com/mailgun/mailgun-go/v4"
    "github.com/mailgun/mailgun-go/v4/events"
)

func main() {

    // You can find the Private API Key in your Account Menu, under "Settings":
    // (https://app.mailgun.com/app/account/security)
    mg := mailgun.NewMailgun("your-domain.com", "private-api-key")

    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {

        var payload mailgun.WebhookPayload
        if err := json.NewDecoder(r.Body).Decode(&payload); err != nil {
            fmt.Printf("decode JSON error: %s", err)
            w.WriteHeader(http.StatusNotAcceptable)
            return
        }

        verified, err := mg.VerifyWebhookSignature(payload.Signature)
        if err != nil {
            fmt.Printf("verify error: %s\n", err)
            w.WriteHeader(http.StatusNotAcceptable)
            return
        }

        if !verified {
            w.WriteHeader(http.StatusNotAcceptable)
            fmt.Printf("failed verification %+v\n", payload.Signature)
            return
        }

        fmt.Printf("Verified Signature\n")

        // Parse the event provided by the webhook payload
        e, err := mailgun.ParseEvent(payload.EventData)
        if err != nil {
            fmt.Printf("parse event error: %s\n", err)
            return
        }

        switch event := e.(type) {
        case *events.Accepted:
            fmt.Printf("Accepted: auth: %t\n", event.Flags.IsAuthenticated)
        case *events.Delivered:
            fmt.Printf("Delivered transport: %s\n", event.Envelope.Transport)
        }
    })

    fmt.Println("Serve on :9090...")
    if err := http.ListenAndServe(":9090", nil); err != nil {
        fmt.Printf("serve error: %s\n", err)
        os.Exit(1)
    }
}

Using Templates

Templates enable you to create message templates on your Mailgun account and then populate the data variables at send-time. This allows you to have your layout and design managed on the server and handle the data on the client. The template variables are added as a JSON stringified X-Mailgun-Variables header. For example, if you have a template to send a password reset link, you could do the following:

package main

import (
    "context"
    "fmt"
    "log"
    "time"

    "github.com/mailgun/mailgun-go/v4"
)

// Your available domain names can be found here:
// (https://app.mailgun.com/app/domains)
var yourDomain string = "your-domain-name" // e.g. mg.yourcompany.com

// You can find the Private API Key in your Account Menu, under "Settings":
// (https://app.mailgun.com/app/account/security)
var privateAPIKey string = "your-private-key"


func main() {
    // Create an instance of the Mailgun Client
    mg := mailgun.NewMailgun(yourDomain, privateAPIKey)

    sender := "sender@example.com"
    subject := "Fancy subject!"
    body := ""
    recipient := "recipient@example.com"

    // The message object allows you to add attachments and Bcc recipients
        message := mg.NewMessage(sender, subject, body, recipient)
        message.SetTemplate("passwordReset")
        message.AddTemplateVariable("passwordResetLink", "some link to your site unique to your user")

    ctx, cancel := context.WithTimeout(context.Background(), time.Second*10)
    defer cancel()

    // Send the message with a 10 second timeout
    resp, id, err := mg.Send(ctx, message)

    if err != nil {
        log.Fatal(err)
    }

    fmt.Printf("ID: %s Resp: %s\n", id, resp)
}

The official mailgun documentation includes examples using this library. Go here and click on the "Go" button at the top of the page.

EU Region

European customers will need to change the default API Base to access your domains

mg := mailgun.NewMailgun("your-domain.com", "private-api-key")
mg.SetAPIBase(mailgun.APIBaseEU)

Installation

If you are using golang modules make sure you include the /v4 at the end of your import paths

$ go get github.com/mailgun/mailgun-go/v4

If you are not using golang modules, you can drop the /v4 at the end of the import path. As long as you are using the latest 1.10 or 1.11 golang release, import paths that end in /v4 in your code should work fine even if you do not have golang modules enabled for your project.

$ go get github.com/mailgun/mailgun-go

NOTE for go dep users

Using version 3 of the mailgun-go library with go dep currently results in the following error

"github.com/mailgun/mailgun-go/v4/events", which contains malformed code: no package exists at ...

This is a known bug in go dep. You can follow the PR to fix this bug here Until this bug is fixed, the best way to use version 3 of the mailgun-go library is to use the golang community supported golang modules.

Testing

WARNING - running the tests will cost you money!

To run the tests various environment variables must be set. These are:

• MG_DOMAIN is the domain name - this is a value registered in the Mailgun admin interface.
• MG_PUBLIC_API_KEY is the Public Validation API key - you can get this value from the Mailgun security page
• MG_API_KEY is the Private API key - you can get this value from the Mailgun security page
• MG_EMAIL_TO is the email address used in various sending tests.

and finally

• MG_SPEND_MONEY if this value is set the part of the test that use the API to actually send email will be run - be aware this will count on your quota and this will cost you money.

The code is released under a 3-clause BSD license. See the LICENSE file for more information.