Use CloudAMQP from Crystal

A minimal example of publishing and consuming messages with amqp-client.cr, against CloudAMQP or any AMQP 0-9-1 broker such as LavinMQ or RabbitMQ.

All AMQP code is in src/example.cr:

• publish publishes a persistent message and blocks until the broker has confirmed it. amqp-client.cr publishes transient messages unless delivery_mode: 2 is set.
• consume consumes with a prefetch of 10, acking each message after the block returns. subscribe acks automatically unless no_ack: false is passed.
• connect connects using the CLOUDAMQP_URL environment variable, and verifies the server certificate for amqps:// URLs.

amqp-client.cr doesn't reconnect: if the connection is lost, the programs exit.

Usage

Tool versions are in mise.toml; install them with mise, or use any Crystal 1.x.

shards build
export CLOUDAMQP_URL="amqps://user:password@host/vhost"
bin/worker      # in one terminal
bin/publisher   # in another

Without CLOUDAMQP_URL it connects to amqp://guest:guest@localhost.

Tests

crystal spec publishes and consumes a message through a real broker on localhost. CI runs it against LavinMQ, together with crystal tool format and ameba.