This document is a guide on using the AWS Ruby SDK, highlighting its advantages over the CLI for managing AWS tasks more efficiently. It covers the differences between SDK versions, the importance of not exposing credentials, and provides examples of various operations. The document encourages learning the SDK for its simplicity and recommends exploring the Python SDK for those who find Ruby challenging.

1. An Engineer’s
Guide to the
AWS Ruby SDK

2. Caveat:
I’m an Engineer, not a developer.
I script, I don’t code, this won’t be pretty...

3. Goals of this presentation
▷Introduction
▷Quick overview of Ruby SDK
▷Pass on some lessons learned
▷Save you some time and pain
▷Recommendations based on
experience

4. So why use the Ruby SDK?
Besides CLI Naming inconsistencies…

5. Besides being a good way to
learn AWS…
▷I didn’t want to have to go to the web
interface every time I wanted to do a
simple task like adding a security group or
generating a key pair
▷Although the CLI has quite good help, the
naming and use of tags and switches is
frustratingly inconsistent
▷The SDK is actually nicer to deal with
than the CLI and is far more consistent

6. I already had my own Ruby
based deployment tool [1]
▷Supported packer, managing VMs and
many other things
▷I could create and deploy a simple
instance for testing with one or two
commands
▷Wrote the JSON/config for me based on
sensible defaults (also avoid typos)
▷Automatically check IP rules, keys, etc
[1] https://github.com/lateralblast/mode

7. Using the AWS Ruby SDK
A high level view…

8. First: Some really obvious stuff:
▷Never put credentials in your code
▷Never check in files with credentials
Now, on with the code mix:
▷Quick overview
▷Standard examples from the documentation
▷Some examples I came up with

9. Version 1:
More straightforward
Simpler to get started
No resources, pagination
More examples
Less functionality
No longer current
Two versions of SDK:
Version 2:
Less straightforward
Simpler to use long term
Resources, pagination, waiters
Less examples
More functionality
Current
…can use both in same code if needed

10. Client:
More procedural
More code
Easier for those used to the
CLI
Far more examples
Bulk operations
SDK V2: Two approaches…
Resource:
More object like
Less code
Easier for those used to
Ruby
Very few examples
Object manipulation

11. Using the AWS Ruby SDK
Some slightly heavier lifting… V1 v V2…

12. Version 1:
ec2 = AWS::EC2.new
ec2.instances.each do |instance|
instance.terminate
end
SDK v2 has resources…
Version 2:
ec2 = Aws::EC2::Resource.new
ec2.instances.terminate
…in reality didn’t use resources as much as I would normally

13. Version 1:
client = AWS::S3::Client.new
resp = client.list_objects(bucket_name:name)
while resp.truncated do
marker = resp.marker || resp.contents.last.key
resp = client.list_objects(
bucket_name: bucket_name,
marker: marker
)
puts resp.contents.map(&:key)
end
SDK v2 has pagination…
Version 2:
client = Aws::S3::Client.new
resp = client.list_objects(bucket_name:name)
resp.each do |page|
puts page.contents(&:key)
end
…main reason to use SDK v2

14. Version 1:
MAX_ATTEMPTS = 10
client = AWS::EC2::Client.new
instance = e2c.instances[instance_id]
running = false
attempts = 0
until running do
if instance.status == :running
running = true
else
attempts += 1
break if attempts >= MAX_ATTEMPTS
sleep(10)
end
end
SDK v2 has waiters…
Version 2:
client = Aws::EC2::Client.new
client.wait_until(
:instance_running,
instance_ids: [instance_id]
)
…yet another reason to use SDK v2

15. Using the AWS Ruby SDK
A mix of V2 SDK examples…

16. Iterating over some bucket objects…
Version 2:
s3 = Aws::S3::Resource.new
S3.bucket(name).objects.each do |object|
puts object.key
end
…another reason to use SDK v2

17. Version 2 Client:
client = Aws::S3::Client.new
client.wait_until(
:object_exists,
bucket: bucket_name,
key: object_key
)
SDK v2 client and resource
(S3)…
Version 2 Resource:
s3 = Aws::S3::Resource.new
S3.bucket(bucket_name).object(object_key).wait_until_exists
…yet another reason to use SDK v2

18. Version 2 Client:
ec2 = Aws::EC2::Client.new
instance_ids = []
ec2.describe_instances['reservations'].each do |reservation|
reservation['instances'].each do |instance|
instance_ids.push instance.instance_id
end
end
ec2.reboot_instances(instance_ids: instance_ids)
SDK v2 client and resource
(EC2)…
Version 2 Resource:
ec2 = Aws::EC2::Resource.new
ec2.instances.each do |instance|
instance.reboot
end
…yet another reason to use SDK v2

19. Version 2 Client:
ec2 = Aws::EC2::Client.new
key_pair = ec2.create_key_pair({
key_name: key_name
}).key_material
key_file = “/location_of_key_file.key”
File.open(key_file, ’w’) {
|f| f.write(key_pair)
}
Creating and saving a key pair…
…yet another reason to use SDK v2

20. Version 2 Resource Object Upload:
s3 = Aws::S3::Resource.new
s3.bucket(bucket_name).object(object_key).upload_file(file_name)
Version 2 Client Object Download:
s3 = Aws::S3::Client.new
s3.get_object({
bucket: bucket_name, key: object_key,
}, target: file_name )
S3 bucket uploads and downloads…
…yet another reason to use SDK v2

21. Summary:
SDK >> CLI, and take a look at the Python SDK…

22. So where’s this all going…
▷SDK is worth learning
▷Far nicer and more consistent than the CLI
▷Easy to iterate through items
▷Object like in nature, more malleable
▷More elegant, less code
▷Can wait rather than sleep
▷So take a look at the SDK
▷While you’re at it, take a look at the Python
SDK, it’s more straight forward than Ruby

23. Huh, what you say? Python SDK?
▷But regex is torture in Python…
▷If you’re familiar with Python, and haven’t
got an existing codebase of Ruby to
support I’d recommend using the Python
SDK
▷Python SDK is a bit more straight forward
▷A lot of other deployment and config tools
are written in Python (less confusion)
▷At some point you’ll want to get/do
something using REST (borked on Ruby)

24. Thanks for your patience
richard@lateralblast.com.au