Redis command: EVAL/EVALSHA

[GoogleCodeExporter]

I'd like to propose to add following redis command: EVAL - EVALSHA (LUA 
Scripting) as defined in http://www.redis.io/commands/eval

This redis command is supported from version 2.2.106 as experimental and will 
be fully integrated in redis 2.6.0. Redis 2.6 RC1 is planned for end of 
2011.Redis 2.4 as branch does not support EVAL/EVALSHA. Source: 
http://antirez.com/post/short-term-redis-plans.html. 

At the moment we use alternative c# library, however we would like to move to 
full async IO, since we have high-performance requirements for our app. At the 
moment we use following functions from alternative library (we have 3 types of 
results that we receive (string, long, List<string>):

public string GetEvalStr(string body, int numOfArgs, params string[] args)
public long GetEvalLong(string body, int numOfArgs, params string[] args)
public List<string> GetEvalMultiData(string body, int numOfArgs, params 
string[] args)

public string GetEvalSha1Str(string body, int numOfArgs, params string[] args)
public long GetEvalSha1Long(string body, int numOfArgs, params string[] args)
public List<string> GetEvalSha1MultiData(string body, int numOfArgs, params 
string[] args)

What is the expected output? What do you see instead?
I believe that whole EVAL scripting is not supported. We suggest to add 
EVAL/EVALSHA1 commands.

What version of the product are you using? On what operating system?
Latest library from 2011-12-27 / Redis 2.2.106 (must have scripting support !). 
Client: WIN7 /NET 4.0, REDIS server on Ubuntu 10.04.

Original issue reported on code.google.com by mark.v...@gmail.com on 27 Dec 2011 at 10:35

[GoogleCodeExporter]

Yes, that is on my roadmap too. Only problem is getting a version that supports 
it! I'll take a look at the version you cite...

Original comment by marc.gravell on 27 Dec 2011 at 11:53

• Changed state: Accepted
• Added labels: Type-Enhancement
• Removed labels: Type-Defect

[GoogleCodeExporter]

I have asked our sysadmin to verify our version... He suggested to use version 
2.2.111, that is what we use in production.. (it's in the 2.2. scripting branch)

https://github.com/antirez/redis/tree/2.2-scripting

Original comment by mark.v...@gmail.com on 27 Dec 2011 at 1:30

[GoogleCodeExporter]

I have made first implementation... It's very rough code, however as a general 
concept - it works.. At the end I have added a few test cases.

https://gist.github.com/1524339

Original comment by mark.v...@gmail.com on 27 Dec 2011 at 4:57

[GoogleCodeExporter]

Thanks hugely - sounds promising. Just to set expectation: I'm taking things 
leisurely between Xmas and new-year, but will review this (and try sorting out  
2.2 on my VM) in the new year.

Original comment by marc.gravell on 27 Dec 2011 at 5:01

[GoogleCodeExporter]

I have added some additional commands, that we needed, but are only supported 
in Redis Unstable (they will be fully supported in Redis 2.6)

https://gist.github.com/1836949 is our public draft of following supported 
commands:

        http://redis.io/commands/eval
        Task<string> EvalScriptLoad(int db, bool queueJump, string[] args);
        Task<string[]> EvalScriptExists(int db, bool queueJump, params string[] args);
        Task<string> EvalScriptFlushAll(int db, bool queueJump);
        Task<string> EvalScriptKill(int db, bool queueJump);

//we also added a command that we were missing when debugging (it helps, when 
you can put your own string to see in redis monitor screen)
Task<string> ServerEcho( bool queueJump, params string[] args);

Original comment by mark.v...@gmail.com on 15 Feb 2012 at 4:16

[GoogleCodeExporter]

Awesome! I'll try to yank "unstable" to see how it works.

Original comment by marc.gravell on 15 Feb 2012 at 8:28

[GoogleCodeExporter]

I have found a problem, that when running Redis Eval commands (see our link to 
gist above) our lua scripts can change current database (example in lua script 
would be: redis.call('select',2)). The problem is, that Booksleeve client 
library doesn't know the current database for this connection after comming 
back from Redis lua call. We can't solve this in Redis lua script as lua script 
can't read current database to save it to lua variable that would be selected 
before end of script.

Since booksleeve keeps internal database number in RedisCommand.cs (int db) I 
think it would be useful to have some method, to reset internal Booksleeve db 
number. 

Booksleeve would in that case add "select " to next redismessage.  Something 
like RedisCommand.InvalidateDBNumber();

Original comment by mark.v...@gmail.com on 1 Jun 2012 at 1:29

[GoogleCodeExporter]

sure, makes sense. Of course, it could just issue a SELECT expectedNumber 
*after* a LUA script - same effect overall, but no need for an "invalidate" 
number.

Original comment by marc.gravell on 1 Jun 2012 at 5:38

[GoogleCodeExporter]

a .Scripting node is now available under the connection; the implementation is 
a bit more advanced, handling all the caching etc at the server, and supporting 
different return shapes (not just string)

Original comment by marc.gravell on 17 Oct 2012 at 11:57

• Changed state: Fixed