Generate Memory Report as valid CSV

[joshuaflanagan]

The current memory report does not emit valid CSV if a Redis key contains a comma or quotes.

These are perfectly valid characters in a Redis key:

SET "First,Second" 1
SET 'quotes"are"valid' 2
KEYS *
#=>
1) "quotes\"are\"valid"
2) "First,Second"

The current code makes no attempt to escape these characters, so the generated file is impossible to parse from any other application if one of these characters exist in the rdb.

Use the standard library CSV module to ensure valid CSV is always generated.

[joshuaflanagan]

I've updated the PR to add python 3 compatibility, fixing the build.

[amotzg]

@joshuaflanagan great catch! It's an important corner that have never been addressed.

Small concern about your fix though, previous code used latin-1 encoding to keep byte values as is, your valid CSV solution use UTF-8. It will support Unicode characters but will change binary key names.

Library user have a way to control desired byte/text manipulation by setting the string escape parameter. MemoryCallback.emit_record() take care of this. With previous code, an attempt to use UTF-8 parsing would have fail, but the default option work for all cases.
A possible resolution for this is to add code to allow MemoryCallback.__init__() to set stream encoding, something like:
self._stream.set_encoding('utf8' if self._escape == encodehelpers.STRING_ESCAPE_UTF8 else 'latin-1')

Can you please address this issue in this PR?