Accept key prefix in connection string

[alrz]

using WithKeyPrefix must be supported in each library that depends on SE.R. It would really help if we could pass the prefix in the connection string just like defaultDatabase.

[NickCraver]

@mgravell I remember there was a reason we never implemented this, including when Stack used it and channelPrefix was added...but I can't recall why now, any chance you remember?

I'm admittedly not sure how the behavior would with the existing methods kick in, e.g. would they concat an additional prefix? That's likely counter to what's wanted because "starts with" it usually the intuitive behavior. For example if the base was prefix1 then the key is prefix1:key, but if .WithKeyPrefix() is called on the now-default IDatabase say with prefix2 would the result be:

• prefix2:prefix1:key (what code would naively do)
• prefix1:prefix2:key (actually a prefix-suffix)
• prefix2:key (acting as an override)

Things like this come into play if there's some global default. Each of the above options is arguable, but not intuitive, and the last could allow an "escape" is the intent is to encapsulate keys inside an external prefix. It may be just because of the above questions that we leave it to downstream libraries, because there are behavioral decisions in supporting it.

[alrz]

Note that the reason for this is that clients may only access to a specific key prefix so I think the one specified in connection string should be considered the global default (not overridable)

[NickCraver]

@alrz Understood - I assumed the same, but all the questions remain :) What specific thing are you using that doesn't support this today?

[alrz]

I've filed this for Orleans as well. This was kind of blocking due to the keyspace perm but didn't find it in either side.

[mgravell]

If I may reframe/restate, is this correct?

• ACLs in current Redis make key prefix more relevant
• some client scenarios do not consider explicit key prefix APIs
• therefore an implicit key prefix in the connection string would provide instant support to more scenarios

[alrz]

That's exactly correct, I believe.

[NickCraver]

If the intent is ACLs, then it seems like the intended behavior wouldn't be something like "globalKeyPrefix", which always comes first for all commands (would it apply to channels? Or no because there exists an option for that which could be set too?)