Anonymous Telegram Chat Bot [UNDER DEVELOPMENT]

Deployment

Terraform Backend

First we create a S3 bucket to store Terraform state, a DynamoDB table to persist Terraform state lock and a S3 bucket to deploy Lambda function code bundles. The Terraform state for this init stack is being kept locally.

cd infra/init
terraform init # Run once

terraform plan \
-var aws_region=<AWS_REGION>\
-var terraform_state_bucket=<S3_TERRAFORM_STATE_BUCKET_NAME> \
-var lambda_bucket=<S3_CODE_BUCKET_NAME> \
-out init.tfplan

terraform apply "init.tfplan"

Build and Bundle

cd bot

GOARCH=amd64 GOOS=linux go build -o bootstrap main.go

Note: In order to use the binary as the Lambda handler, it should be named bootstrap.

Create a zip bundle from the built binary

zip lambda_function.zip bootstrap

Upload Bundle

Upload the build zip bundle to S3:

aws s3 cp lambda_function.zip s3://<S3_CODE_BUCKET_NAME>/lambda_function.zip

Deploy AWS Resources

Add Terraform Variables File

Create a file named infra/terraform.tfvars:

aws_region     = <AWS_REGION>
lambda_bucket  = <S3_CODE_BUCKET_NAME>
bot_token      = <TELEGRAM_BOT_TOKEN>

You can also pass these variables to terraform plan command using multiple -var options.

Initialize Terraform

Create a Terraform backend configuration file named infra/backend_config.hcl:

bucket         = <S3_TERRAFORM_STATE_BUCKET_NAME>
region         = <AWS_REGION>

Initialize the main Terraform stack:

cd infra

terraform init -backend-config="backend_config.hcl" # Run once

Deploy

Use terraform plan to create a changeset and run terraform apply command to deploy the changeset on AWS:

cd infra

terraform plan -out main.tfplan
terraform apply "main.tfplan"

Register Bot Webhook

Get the API_GATEWAY_STAGE_INVOCATION_URL from terraform output and register it as the webhook on telegram.

curl https://api.telegram.org/bot<BOT_TOKEN>/setWebhook \
-F "url=<API_GATEWAY_STAGE_INVOCATION_URL>

Local Development

Use docker compose to run local DynamoDB and also a local development web server on port 8080:

export BOT_TOKEN=<BOT_TOKEN>
docker compose up -d

After applying a change in the bot code, to update the local bot in the docker container:

docker compose restart bot

Run a reverse proxy tool with a public secure API gateway on your local 8080 port.
For example using ngrok:

ngrok http 8080

Register the local bot on Telegram using the ngrok's forwarding endpoint:

curl https://api.telegram.org/bot<BOT_TOKEN>/setWebhook \
-F "url=<NGROK_FORWARDING_ENDPOINT>

You can see the incoming update requests sent by Telegram on ngrok's web interface: http://127.0.0.1:4040.