notify/

notify

The notify package provides pluggable implementations for sending notifications via Email (SMTP), Slack, and Microsoft Teams (both Incoming Webhook and Graph API).

Features

• Send email with plain text, HTML, and attachments
• Post Slack messages with colored attachments
• Send Microsoft Teams messages via:
  • Incoming webhook
  • Graph API (channel messages)
• Configurable headers, TLS settings, and authentication
• Typed error semantics for transient vs permanent failures
• Shared HTTP client defaults and per-request timeouts

Package Overview

🔌 Interfaces

📦 Subpackages

• email – SMTP email sender with STARTTLS, auth, attachments
• slack – Sends messages to Slack using chat.postMessage
• msteams – Sends cards via Microsoft Teams webhook
• msteamsgraph – Sends rich messages using Graph API
• utils – Shared HTTP client abstraction
• utils/errors.go – Typed error helpers (transient vs permanent)

Error Semantics

All HTTP-based notifiers return typed errors via utils.Wrap:

• transient: safe to retry (timeouts, 5xx, 429, 408, network errors)
• permanent: do not retry (4xx, invalid payloads, auth errors)

Use utils.IsTransient(err) to decide whether to retry.

Defaults & Timeouts

HTTP clients share a default per-request timeout of 10s. You can override it via:

• slack.WithTimeout(...)
• msteams.WithTimeout(...)
• msteamsgraph.WithTimeout(...)

Usage

Email

cfg := email.SMTPConfig{
    Host:     "smtp.example.com",
    Port:     587,
    From:     "noreply@example.com",
    Username: "user",
    Password: "pass",
}

client := email.New(cfg)
msg := email.Message{
    To:      []string{"recipient@example.com"},
    Subject: "Hello",
    Body:    "This is a test email",
}

_ = client.Send(context.Background(), msg)

Slack

client := slack.NewWithToken("xoxb-your-token")
msg := slack.Slack{
    Channel: "#alerts",
    Attachments: []slack.Attachment{{
        Color: "danger",
        Title: "High Load",
        Text:  "CPU usage exceeds 90%",
    }},
}
_, _ = client.Send(context.Background(), msg)

MS Teams (Webhook)

client := msteams.New()
msg := msteams.MSTeams{
    Title: "Deployment Success",
    Text:  "The app was deployed successfully.",
}
_, _ = client.Send(context.Background(), msg, "https://outlook.office.com/webhook/...")

MS Teams (Graph API)

client := msteamsgraph.NewWithToken("BearerToken")
msg := msteamsgraph.Message{
    Body: msteamsgraph.ItemBody{
        ContentType: "html",
        Content:     "✅ All systems operational.",
    },
}
_, _ = client.SendChannel(context.Background(), "team-id", "channel-id", msg)

• All notifiers accept custom utils.HTTPDoer for dependency injection and testability.
• Use mocks or replace HttpClient to simulate behavior during unit tests.