fix(credentials) better handling if credential providers fail (#22)

Author: Tieske

README.md

@@ -149,6 +149,8 @@ Release process:
 
  - fix: relax validation to not validate some generic metadata fields. Encountered
  while trying to use Lambda [#21](https://github.com/Kong/lua-resty-aws/pull/21)
+ - fix: better error handling when credential providers fail to load
+ [#22](https://github.com/Kong/lua-resty-aws/pull/22)
 
 ### 0.5.1 (01-Jun-2022)
 

src/resty/aws/init.lua

@@ -480,9 +480,14 @@ function AWS:new(config)
  return creds, err
  end
  else
- -- not implemented yet
- aws_instance[class_name] = function(self, opts)
- error(("'%s' hasn't been implemented yet"):format(class_name), 2)
+ if cred_class:find("module 'resty.aws.credentials." .. class_name .. "' not found", 1, true) then
+ -- not implemented yet
+ aws_instance[class_name] = function(self, opts)
+ error(("'%s' hasn't been implemented yet"):format(class_name), 2)
+ end
+ else
+ -- some other error, bail out
+ error(cred_class)
  end
  end
  end