SAM template environment variables use map, list, associative array?

Question

I've only seen examples with single values in SAM templates:

Environment:
  Variables:
    TABLE_NAME: my-table

I want to do something like this but doesn't seem to work:

Environment:
  Variables:
      myVar:
      -   prop1: aaa
          prop2: sdfsdfsd
          prop3: ssss
      -   prop1: bbb
          prop2: wwwwww
          prop3: aaaaa

I want to have an environment variable that is like a list of objects. I could store a delimited string and parse it myself but I'd prefer to have it be like an object/map/list like if I'm ready a YAML file.

b.b3rn4rd · Accepted Answer · 2018-10-10T00:11:04.743

2

The closest you can do is to json encode the value for your environmental variable and decode it using the runtime language:

 Environment:
  Variables:
    USER: '{"name": "john", "surname": "galt"}'

If you want to prevent decoding json on each request, move your decoding logic outside the handler, in this case code won't be re-executed while lambda is hot.

Any declarations in your Lambda function code (outside the handler code, see Programming Model) remains initialized, providing additional optimization when the function is invoked again. For example, if your Lambda function establishes a database connection, instead of reestablishing the connection, the original connection is used in subsequent invocations. We suggest adding logic in your code to check if a connection exists before creating one.

Read about lambda execution model

I personally would create a json file, store it in s3 bucket and use an environment variable to specify s3 url to that file. Additionally, use the same technique I mentioned above or use even more complicated caching mechanism depending on the situation when retrieving the config file

edited Oct 10 '18 at 00:11

answered Sep 26 '18 at 01:19

b.b3rn4rd

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i assumed that was the only way which would be too bad. This would murder performance if I had to decode a yaml string for EVERY request right? – red888 Sep 26 '18 at 14:42
is doing a yaml or json decode on each request in a lambda really bad? – red888 Oct 09 '18 at 20:19
@red888 if you want to prevent decoding on each request, move your code outside the handler, see the updated answer – b.b3rn4rd Oct 10 '18 at 00:11
How does that work? The handler is the entry point right? Do I define a function outside handler and call it inside the handler? – red888 Oct 10 '18 at 00:20

SAM template environment variables use map, list, associative array?

1 Answers1