v1.0.0

code.nochebuena.dev/einherjar/smtp

Architecture Decisions Resolved

Decision	Outcome
No-op when Host empty	`New` returns a silent no-op — SMTP absence never blocks a transaction (account creation, order placement)
Interface name	`Sender` (N-4 agent noun) — single `Send` method; not `Provider`
BCC handling	In SMTP envelope only (RCPT TO) — never written to message headers; RFC 5321/5322 compliant
Attachment encoding	`base64` with `multipart/mixed`; body in `quoted-printable`
Template rendering	Separate from `Send` — caller renders to string, assigns to `Message.Body`; no coupling between rendering and transport
External dependencies	None — pure stdlib (`net/smtp`, `mime/multipart`, `html/template`)
Health priority	`LevelDegraded` — email delivery failure degrades but does not halt the service

API

import "code.nochebuena.dev/einherjar/smtp"

// Interfaces
type Sender interface {
    Send(ctx context.Context, msg Message) error
}
type Component interface {
    lifecycle.Component
    observability.Checkable
    observability.Identifiable
    Sender
}

// Value types
type Message struct {
    To          []string
    CC          []string
    BCC         []string    // in SMTP envelope only; never in headers
    ReplyTo     string
    Subject     string
    Body        string
    ContentType string      // defaults to "text/plain"
    Attachments []Attachment
}
type Attachment struct {
    Name        string
    ContentType string      // defaults to "application/octet-stream"
    Data        io.Reader   // consumed once on Send; must not be reused
}

// Config
type Config struct {
    Host     string `env:"EINHERJAR_SMTP_HOST"`
    Port     int    `env:"EINHERJAR_SMTP_PORT"     envDefault:"587"`
    User     string `env:"EINHERJAR_SMTP_USER"`
    Password string `env:"EINHERJAR_SMTP_PASSWORD"`
    From     string `env:"EINHERJAR_SMTP_FROM"`
}
func DefaultConfig() Config

// Constructor — returns no-op Component when cfg.Host is empty
func New(logger logging.Logger, cfg Config) Component

// Template rendering (separate from Send)
type Template struct { /* unexported */ }
func ParseFS(fsys fs.FS, patterns ...string) (*Template, error)
func (t *Template) Render(name string, data any) (string, error)

Install

go get code.nochebuena.dev/einherjar/smtp@v1.0.0

Dependencies

Module	Version	Role
`code.nochebuena.dev/einherjar/contracts`	v1.0.0	`lifecycle.Component`, `observability.Checkable`, `logging.Logger`
`code.nochebuena.dev/einherjar/core`	v1.0.0	`xerrors`

Downloads

1 Release 1 Tag

Release v1.0.0 Stable

v1.0.0

Architecture Decisions Resolved

API

Install

Dependencies