loader-dmarc-imap

A small Go app that connects to an IMAP inbox, downloads messages, finds DMARC aggregate reports in XML/ZIP/GZIP attachments, and prints parsed report details to stdout.

This project uses Cobra CLI commands.

Requirements

• Go 1.25+
• IMAP account credentials

Configuration

Set environment variables for a single IMAP account:

• IMAP_SERVER (required)
• IMAP_PORT (optional, defaults to 993)
• IMAP_USERNAME (required)
• IMAP_PASSWORD (required)
• IMAP_MAILBOX (optional, defaults to INBOX)
• IMAP_SKIP_TLS_VERIFY (optional, defaults to false)
• IMAP_ACCOUNT_NAME (optional, used for command filtering)
• DEBUG (optional, defaults to false; when true, saves parsed DMARC XML files)
• DEBUG_XML_DIR (optional, defaults to DEBUG/XML)

For multiple IMAP accounts, use indexed environment variables or a JSON array.

Example indexed account configuration:

IMAP_ACCOUNT_1_NAME=rua
IMAP_ACCOUNT_1_SERVER=imap.example.com
IMAP_ACCOUNT_1_PORT=993
IMAP_ACCOUNT_1_USERNAME=rua@example.com
IMAP_ACCOUNT_1_PASSWORD=secret
IMAP_ACCOUNT_1_MAILBOX=INBOX
IMAP_ACCOUNT_1_SKIP_TLS_VERIFY=false

IMAP_ACCOUNT_2_NAME=ruf
IMAP_ACCOUNT_2_SERVER=imap.example.com
IMAP_ACCOUNT_2_USERNAME=ruf@example.com
IMAP_ACCOUNT_2_PASSWORD=secret
IMAP_ACCOUNT_2_MAILBOX=INBOX

Example JSON configuration:

IMAP_ACCOUNTS=[
  {"name":"rua","server":"imap.example.com","port":993,"username":"rua@example.com","password":"secret","mailbox":"INBOX","skip_tls_verify":false},
  {"name":"ruf","server":"imap.example.com","username":"ruf@example.com","password":"secret","mailbox":"INBOX"}
]

The app automatically loads .env from the current working directory before reading environment variables. Existing exported environment variables still take precedence.

If a value contains special characters (for example #), wrap it in quotes in .env:

IMAP_PASSWORD="#SQNq8Qi*hKp4PQ$"

Run

cp .env.example .env
# edit .env values

go mod tidy
go run ./cmd/dmarc load --type=all
# or run a type-specific command
go run ./cmd/dmarc load-rua
go run ./cmd/dmarc load-ruf
go run ./cmd/dmarc load-tlsrpt

Build As dmarc

go build -o dmarc ./cmd/dmarc
./dmarc load

Project Structure

loader-dmarc-imap/
  cmd/dmarc/
    main.go                 # CLI entry point
  internal/
    config/
      config.go             # Configuration loading
    dmarc/
      types.go              # DMARC report data structures
      parser.go             # DMARC XML parsing and decompression
      debugxml.go           # Debug XML saving
      mail.go               # Email message parsing helpers
      time.go               # Time formatting utilities
    loader/
      loader.go             # IMAP connection and report fetching
  go.mod
  README.md

This project follows standard Go project layout conventions with CLI code in cmd/ and reusable packages in internal/.