Stable documented output formats

[simonw]

Before 1.0 I want to have stable output formats - in particular for the create command.

I want to provide:

• JSON (the current default is OK here)
• INI style config that can be written to ~/.AWS
• Shell syntax that sets environment variables

[simonw]

Logging messages go to stderr, so even though they are displayed by default if the user does this it will work as expected:

% s3-credentials create hello-simon-world-bucket-2 --format ini --create-bucket > ini.txt
Created user: s3.read-write.hello-simon-world-bucket-2 with permissions boundary: arn:aws:iam::aws:policy/AmazonS3FullAccess
Attached policy s3.read-write.hello-simon-world-bucket-2 to user s3.read-write.hello-simon-world-bucket-2
Created access key for user: s3.read-write.hello-simon-world-bucket-2
% cat ini.txt 
aws_access_key_id=AKIAWXFXAIOZADC3B4RA
aws_secret_access_key=acdecuec/lfz56oo4jE2+glHJIAeKmhS3zgXUF2Nc9

[simonw]

With ini in there I don't actually need the one that outputs shell environment variable syntax, because the ini format works for that already.

% source ini.txt 
% echo $aws_access_key_id
AKIAWXFXAIOZKGXI4PVO

[simonw]

% cat ini.txt 
aws_access_key_id=AKIAWXFXAIOZADC3B4RA
aws_secret_access_key=acdecuec/lfz56oo4jE2+glHJIAeKmhS3zgXUF2Nc9

It turns out this isn't actually a valid INI file - in as much as Python's configparser standard library module refuses to handle it because it's missing the header:

>>> p = configparser.ConfigParser()
>>> p.read("ini.txt")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/simon/.pyenv/versions/3.10.0/lib/python3.10/configparser.py", line 698, in read
    self._read(fp, filename)
  File "/Users/simon/.pyenv/versions/3.10.0/lib/python3.10/configparser.py", line 1086, in _read
    raise MissingSectionHeaderError(fpname, lineno, line)
configparser.MissingSectionHeaderError: File contains no section headers.
file: 'ini.txt', line: 1
'aws_access_key_id=AKIAWXFXAIOZKGXI4PVO\n'

[simonw]

On https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-files.html#cli-configure-files-where the example uses a [default] section header in ~/.aws/credentials:

[default]
aws_access_key_id=AKIAIOSFODNN7EXAMPLE
aws_secret_access_key=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY

This would break the source ini.txt trick from #17 (comment) so I maybe do need a --format env option for outputting environment variables.

[simonw]

I forgot to add --format ini support to --duration in #27.