Serverless conditional function deployment by region - server

Question

Following config is extracted from my serverless.yml
service: test-svc
provider:
name: aws
...
functions:
apiHandler:
handler: index.handler
events:
- http: ANY /
- http: 'ANY {proxy+}'
taskHandler:
handler: task.handler
events:
- sqs:
...
alexaHandler:
handler: alexa.handler
events:
- alexaSmartHome: ...
I want to deploy apiHandler and taskHandler function in only region-a
And deploy alexaHandler in region-b, region-c and region-d.
If I execute the command sls deploy --region us-east-1 all three functions will be deployed, but I don't need that. I need only 2 functions to be deployed.
Using sls deploy function is not an option because it only swaps zip file.
Putting alexaHandler in sub-directory with new serverless.yml didn't work because deployment only packs sub-directory and won't include code from the parent directory. (Many codes are shared between 3 function)
Any suggestion to deal with this requirement?

Answer 1

After going through all the serverless plugin list I found above requirement could be achieved through serverless-plugin-select
Using this plugin we can select to deploy only a few functions from serverless.yml depending on stage or region value. In my case using region value.
Following is modified serverless.yml. plugins section added and regions key added in each function.
service: test-svc
plugins:
- serverless-plugin-select
provider:
name: aws
...
functions:
apiHandler:
...
regions:
- us-west-2
taskHandler:
...
regions:
- us-west-2
alexaHandler:
...
regions:
- eu-west-1
- us-east-1
- us-west-2
With the above config, I use the following bash script to deploy for all region.
#!/usr/bin/env bash
serverless deploy --region eu-west-1
serverless deploy --region us-east-1
serverless deploy --region us-west-2

Answer 2

You can conditionally select values in serverless.yml by storing the conditional functions in a custom variable like
### serverless.yml
provider:
name: << aws or your provider >>
runtime: << your runtime, eg nodejs8.10 >>
region: << your aws region >>
stage: ${opt:stage, 'dev'}
custom:
extraCode:
dev:
testing: ${file(testing_only/testing_endpoints.yml)}
prod:
...
## and then at the functions section of serverless.yml
functions:
- ${file(functions/someFunctionsInAFile.yml)}
- ${file(functions/someMoreFunctions.yml)}
- ${self:custom.extraCode.${self:provider.stage}}
When you deploy serverless you should pass in the command line option --stage=myStageName so that when you pass in --stage=dev or --stage=prod the last line in the function section will be blank and nothing will deployed.
If you pass in --stage=testing the last line in the functions sections will be filled with the file set in your custom variable section and then your test code will be deployed.