SIGIL: A Certificate Dispatch System

A Go-based system for stamping and dispatching certificates via email using RabbitMQ for queue management and concurrent processing.

Overview

This system handles three types of certificates for Amrita events:

Certificate Type	Audience	Nature
Certificate of Participation	Event participants	External
Certificate of Achievement	Event winners	External
Certificate of Recognition	Organizers/volunteers	Internal

The workflow for each certificate type follows a pipeline pattern:

1. Process: Parse CSV and publish student data to a certificate queue
2. Generate: Dequeue events, stamp PDFs with names/details, publish to dispatch queue
3. Send: Dequeue events and send certificates via email

Prerequisites

• Go 1.25+
• RabbitMQ 4.1.5+
• pdfcpu for PDF stamping
• Just task runner
• Docker (for RabbitMQ)

Setup

1. Start RabbitMQ:

   docker compose up -d

   Access the management UI at http://localhost:15672 (admin/admin123)

2. Install dependencies:

   go mod download
   just
   pip install pdfcpu  # or see pdfcpu installation docs

3. Configure the application: Copy configs/env.toml.sample to configs/env.toml and update:

   rabbitmq_url = "amqp://admin:admin123@localhost:5672/sigil-vhost"
   storage_dir = "storage/"
   smtp_host = "smtp.host.com"
   smtp_port = 587
   smtp_username = "email"
   smtp_password = "app_password"

4. Build the application:

   just build
   # or: go build -o sigil main.go

Certificate Types & Workflows

1. Certificate of Participation (External)

For event participants.

Step 1: Process CSV into queue

./sigil partprocess storage/data/ESCAPE_ROOM.csv

Reads student_name,student_email from CSV, extracts event name from filename, and publishes to cert_{event_name} queue.

Step 2: Generate certificates

./sigil partcertgen ESCAPE_ROOM templates/participation_cert.pdf

• Listens on cert_ESCAPE_ROOM queue
• Stamps PDF with student name and event name using just stamp-participation
• Saves to storage/cert/ESCAPE_ROOM/{student_email}.pdf
• Publishes to dispatch_internal queue (for internal processing)

Step 3: Send certificates via email

./sigil partcertsend ESCAPE_ROOM

• Listens on dispatch_ESCAPE_ROOM queue
• Sends email with certificate attachment to each recipient
• Subject: "Anokha 2026 - Certificate of Participation"

Participation CSV Format:

student_name,student_email
John Doe,john.doe@example.com

---

2. Certificate of Achievement (External)

For event winners (1st/2nd/3rd place, finalists, etc.).

Step 1: Process winners CSV

./sigil winnerprocess storage/winners.csv

Reads event_name,position,student_name,student_email and publishes to cert_winners queue.

Step 2: Generate winner certificates

./sigil winnergen winners templates/participation_cert.pdf

• Listens on cert_winners queue
• Stamps PDF with name, event name, and position using just stamp-winner
• Saves to storage/cert/winners/{student_email}.pdf
• Publishes to dispatch_winners queue

Step 3: Send winner certificates

./sigil winnersend winners

• Listens on dispatch_winners queue
• Sends email with certificate attachment
• Subject: "Anokha 2026 - Certificate of Achievement"

Winners CSV Format:

event_name,position,student_name,student_email
Agamotto Protocol,1st Place,Shanu VS,shanuvs@example.com
AI VERSE HACKATHON,2nd Place,Praveen C S,praveen@example.com

---

3. Certificate of Recognition (Internal)

For organizers, volunteers, and club heads.

Step 1: Process internal CSV

./sigil internalprocess storage/internal_dept.csv

Reads student_name,student_email,event_name (3 columns) and publishes to cert_internal queue.

Step 2: Send recognition certificates

./sigil internalcertsend <event_name>

• Listens on dispatch_{event_name} queue
• Reads certificate from storage/cert/internal/{student_email}.pdf
• Sends email with certificate attachment
• Subject: "Anokha 2026 - Certificate of Recognition"

Internal CSV Format:

student_name,student_email,event_name
Harshitha Chandrasekar,cb.sc.u4aie23231@cb.students.amrita.edu,Amrita Toastmasters Club – Head

---

Queue Management

Create queues for events

./sigil create events.txt

Reads event names from file and creates:

• cert_{event} queue
• dispatch_{event} queue

events.txt format:

ESCAPE_ROOM
CAMPUS_QUEST
HACKTIDE

Queue naming convention

Queue Pattern	Purpose
cert_{name}	Certificate generation input
dispatch_{name}	Email dispatch input

---

Certificate Templates

Place PDF templates in the templates/ directory:

Template	Use Case
participation_cert.pdf	Participation & Achievement certificates
recognition_cert.pdf	Recognition certificates
appreciation_cert.pdf	(Available for future use)

PDF Stamping (via Just)

The system uses pdfcpu for stamping via the Just task runner:

# Stamp participation/recognition certificates
just stamp-participation "<NAME>" "<EVENT NAME>" <input.pdf> <output.pdf>

# Stamp winner certificates with position
just stamp-winner "<NAME>" "<EVENT NAME>" "<POSITION>" <input.pdf> <output.pdf>

You can adjust text positioning with offset parameters:

just stamp-participation "John Doe" "EVENT" input.pdf output.pdf nameoffset="-115" eventnameoffset="50"

---

Directory Structure

.
├── configs/
│   ├── env.toml           # Application configuration
│   └── env.toml.sample     # Configuration template
├── storage/
│   ├── cert/              # Generated certificates
│   │   ├── {event_name}/  # Participation certificates
│   │   ├── winners/       # Achievement certificates
│   │   └── internal/      # Recognition certificates
│   └── data/              # Participant CSV files
├── templates/             # PDF certificate templates
├── cmd/                   # CLI command implementations
├── pkg/                   # Shared packages
├── compose.yml            # Docker Compose for RabbitMQ
├── justfile               # Build and stamping tasks
└── sigil                  # Compiled binary

---

All CLI Commands

Command	Description
sigil create [events-file]	Create RabbitMQ queues for events
sigil partprocess [csv-file]	Process participation CSV to cert queue
sigil partcertgen [queue] [template]	Generate participation certificates
sigil partcertsend [event_name]	Send participation certificates via email
sigil winnerprocess [csv-file]	Process winners CSV to cert queue
sigil winnergen [queue] [template]	Generate winner certificates
sigil winnersend [name]	Send winner certificates via email
sigil internalprocess [csv-file]	Process internal CSV to cert queue
sigil internalcertsend [event_name]	Send recognition certificates via email

---

Current Status

• ✅ Certificate of Participation workflow
• ✅ Certificate of Achievement workflow
• ✅ Certificate of Recognition workflow
• ✅ RabbitMQ queue management
• ✅ PDF stamping via pdfcpu
• ✅ Email dispatch via SMTP