Crystal AWS

This shard provides clients for various services on AWS. So far, clients implemented are:

• S3
• SQS
• SNS

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     aws:
       github: jgaskins/aws
   

2. Run shards install

Usage

To use each service client, you need to require that client specifically. This avoids loading the entire suite of clients just to use a single one. So for example, to use S3, you would use require "aws/s3".

All AWS clients are instantiated with credentials and a service endpoint. The defaults can be set either programmatically or via environment variables. To set them programmatically, you can set them directly on the AWS namespace:

AWS.access_key_id = "AKIAOMGLOLWTFBBQ"
AWS.secret_access_key = "this is a secret, don't tell anyone"
AWS.region = "us-east-1"

There is no global default endpoint since those are specific to the service. If you wish to use a nonstandard endpoint (for example, to use DigitalOcean Spaces or a MinIO instance instead of S3), you must set it when instantiating the client.

To set the defaults via environment variables

Individual services and their APIs are documented below. All examples assume credentials are set globally and use default AWS endpoints for brevity.

Whenever feasible, method and argument names are snake-cased versions of those of the AWS REST API for ease of translating docs to application code. For example, with SQS, the ReceiveMessage API takes QueueUrl, MaxNumberOfMessages, and WaitTimeSeconds arguments. Your application would call sqs.receive_message(queue_url: url, max_number_of_messages: 10, wait_time_seconds: 20). Additional method overrides are planned to make some of these API calls easier to read.

S3

require "aws/s3"

s3 = AWS::S3::Client.new

s3.list_buckets
s3.list_objects(bucket_name: "my-bucket")
s3.get_object(bucket_name: "my-bucket", key: "my-object")
s3.head_object(bucket_name: "my-bucket", key: "my-object")
s3.put_object(
  bucket_name: "my-bucket",
  key: "my-object",
  headers: HTTP::Headers {
    "Content-Type" => "image/jpeg",
    "Cache-Control" => "private, max-age=3600",
  },
  body: body, # String | IO - if you provide an IO, it MUST be rewindable!
)
s3.delete_object(bucket_name: "my-bucket", key: "my-object")

# Pre-signed URLs for direct uploads or serving <img/> tags for user-uploaded objects
s3.presigned_url("PUT", "my-bucket", "my-object", ttl: 10.minutes)

SNS

require "aws/sns"

sns = AWS::SNS::Client.new

topic = sns.create_topic("my-topic")

# Publishing a message - subject is optional
sns.publish topic_arn: topic.arn, message: "hello"
sns.publish topic_arn: topic.arn, message: "hello", subject: "MySubject"

# This endpoint requires an SQS client and a queue instance from that client. If
# you omit the client, it will create one for you.
sns.subscribe topic: topic.arn, queue: queue, sqs: sqs

SQS

require "aws/sqs"

sqs = AWS::SQS::Client.new

queue = sqs.create_queue(queue_name: "my-queue")

sqs.send_message(
  queue_url: queue.url,
  message_body: "hi",
)
msgs = sqs.receive_message(
  queue_url: queue.url,
  max_number_of_messages: 10,
  wait_time_seconds: 20,
)
msgs.each do |msg|
  process msg
end

sqs.delete_message_batch msgs

Connection pooling

This shard maintains its own connection pools, so you can assign clients directly to a constant for use throughout your application:

require "aws/s3"

S3 = AWS::S3::Client.new

You can use this client anywhere in your application by calling the methods listed above directly on the constant. There is no worry about collisions due to concurrent access. The client manages that transparently.

Contributing

1. Fork it (https://github.com/jgaskins/aws/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Jamie Gaskins - creator and maintainer