go-notification

Post notifications to Slack channels via Incoming Webhooks or the chat.postMessage API.

Two ways to send

Incoming Webhooks — one URL, posts to one channel. Simplest to set up.
Bot token (chat.postMessage) — one token, can post to many channels (if invited). Needed for DMs, threads, updates.

Both are supported.

Option A — Incoming Webhook

Go to https://api.slack.com/apps → Create New App → pick a workspace.
Enable Incoming Webhooks.
Add New Webhook to Workspace, pick a channel.
Copy the webhook URL.

main.go

import "github.com/gopackx/go-notification/channel/chat/slack"

notifier.RegisterChannel("slack", slack.NewWebhook(slack.WebhookConfig{
    URL: os.Getenv("SLACK_WEBHOOK_URL"),
}))

Option B — Bot token

In the same app settings, enable Bots.
Add OAuth scopes: chat:write, chat:write.public.
Install the app to your workspace and copy the Bot User OAuth Token (starts with xoxb-).
Invite the bot into any channel it should post to (/invite @YourBot).

main.go

notifier.RegisterChannel("slack", slack.NewBot(slack.BotConfig{
    Token:          os.Getenv("SLACK_BOT_TOKEN"),
    DefaultChannel: "#alerts",
}))

Sending

main.go

func (n DeployFailed) Via(u notification.Notifiable) []string {
    return []string{"slack"}
}

func (n DeployFailed) ToSlack(u notification.Notifiable) *slack.Message {
    return slack.NewMessage().
        Text("Deploy failed: " + n.Service).
        Attachment(
            slack.NewAttachment().
                Color("danger").
                Field("Commit", n.Commit, true).
                Field("Actor",  n.Actor,  true),
        )
}

For routing per recipient (e.g. DM a specific user), return the user ID or channel ID from RouteNotificationFor("slack"):

main.go

func (u User) RouteNotificationFor(channel string) any {
    if channel == "slack" {
        return u.SlackUserID // "U01ABCD..." for DMs, or "#channel-name"
    }
    return nil
}

Configuration reference

`WebhookConfig`

Field	Type	Required	Description
`URL`	`string`	yes	Incoming webhook URL from the Slack app settings.
`Timeout`	`time.Duration`	no	HTTP timeout per send. Default: `30s`.

`BotConfig`

Field	Type	Required	Description
`Token`	`string`	yes	Bot User OAuth Token (`xoxb-...`).
`DefaultChannel`	`string`	no	Fallback channel if `RouteNotificationFor` returns empty.
`Timeout`	`time.Duration`	no	HTTP timeout per send. Default: `30s`.

Troubleshooting

channel_not_found — bot isn't invited, or channel ID is wrong. Invite with /invite @YourBot.
not_allowed_token_type — you passed a user token (xoxp-) where a bot token (xoxb-) was expected.
Webhook returns 200 but nothing appears — webhook is for a different workspace or the channel was archived.