🌱 Self-heal missing AWS configuration

[AlainODea]

Problem Statement

When AWS directories or config files are missing, this tool can fail ungracefully.

Solution

Self-heal AWS directories and config files when safe, show errors when impossible or unsafe.

[AlainODea]

Fixes #75

[smashling]

I got this error when trying to read the .aws file, but the expected error should have said this was a file and request a rename. This should fail before trying to read the config.properties file.
Exception in thread "main" java.lang.NullPointerException
at java.io.Reader.(Reader.java:78)
at java.io.InputStreamReader.(InputStreamReader.java:72)
at com.okta.tools.OktaAwsConfig.createAwscli(OktaAwsConfig.java:19)
at com.okta.tools.WithOkta.main(WithOkta.java:23)

[AlainODea]

Thank you, @smashling.

I originally had this change in with #92 and didn't properly test it independently.

I have rebased on master and retested and I now get the expected (and far more informative) crash.

It gives an informative error when a pathological file is where ~/.aws/ should be:

Exception in thread "main" java.lang.IllegalStateException: /Users/alain.odea/.aws exists, but is not a directory. Please rename it
	at com.okta.tools.OktaAwsCliAssumeRole.getAwsDirectory(OktaAwsCliAssumeRole.java:583)
	at com.okta.tools.OktaAwsCliAssumeRole.getAwsCredentialsFile(OktaAwsCliAssumeRole.java:559)
	at com.okta.tools.OktaAwsCliAssumeRole.updateCredentialsFile(OktaAwsCliAssumeRole.java:544)
	at com.okta.tools.OktaAwsCliAssumeRole.createAwsProfile(OktaAwsCliAssumeRole.java:522)
	at com.okta.tools.OktaAwsCliAssumeRole.run(OktaAwsCliAssumeRole.java:115)
	at com.okta.tools.WithOkta.main(WithOkta.java:23)

It gives an informative error when a pathological directory is where the credentials file should be:

Exception in thread "main" java.lang.IllegalStateException: /Users/alain.odea/.aws/credentials exists, but is not a regular file. Please rename it
	at com.okta.tools.OktaAwsCliAssumeRole.getAwsCredentialsFile(OktaAwsCliAssumeRole.java:563)
	at com.okta.tools.OktaAwsCliAssumeRole.updateCredentialsFile(OktaAwsCliAssumeRole.java:544)
	at com.okta.tools.OktaAwsCliAssumeRole.createAwsProfile(OktaAwsCliAssumeRole.java:522)
	at com.okta.tools.OktaAwsCliAssumeRole.run(OktaAwsCliAssumeRole.java:115)
	at com.okta.tools.WithOkta.main(WithOkta.java:23)

It gives an informative error when a pathological directory is where the config file should be:

Exception in thread "main" java.lang.IllegalStateException: /Users/alain.odea/.aws/config exists, but is not a regular file. Please rename it
	at com.okta.tools.OktaAwsCliAssumeRole.getAwsConfigFile(OktaAwsCliAssumeRole.java:573)
	at com.okta.tools.OktaAwsCliAssumeRole.updateConfigFile(OktaAwsCliAssumeRole.java:599)
	at com.okta.tools.OktaAwsCliAssumeRole.run(OktaAwsCliAssumeRole.java:116)
	at com.okta.tools.WithOkta.main(WithOkta.java:23)

And it silently recovers from any combination of ~/.aws/, ~/.aws/config, and ~/.aws/credentials being absent.

[smashling]

After merging the test branch with master, the detailed errors came up as expected. This change seems to work as intended.