Lua script for scan with 'match' and 'count' constraints - lua

I am using Jedis. I need a Lua script to scan for a pattern with a specified limit. I don't know how to pass the parameters inside Lua script.
Sample Code:
String script="return {redis.call('SCAN',KEYS[1],'COUNT',KEYS[2],'MATCH',KEYS[3]}";
List<String> response = (List<String>)jedis.eval(script,cursor,COUNT,pattern);
How do I pass these parameters to the script?

Your code has several points to fix.
In scan command, 'match' parameter should be placed prior to 'count'.
You should only use KEYS when it is a place for Redis key. Other things should be represented to ARGV.
You forgot to specify key count while calling Jedis.eval().
So, fixed version of your code is,
String script="return {redis.call('SCAN',ARGV[1],'MATCH',ARGV[2],'COUNT',ARGV[3])}";
List<String> response = (List<String>)jedis.eval(script, 0, cursor, pattern, COUNT);
But I agree Itamar to use Jedis.scan() instead.
Hope this helps.

Related

How to pass arbitrary data between the C module callbacks in FreeRADIUS

What is the proper/recommended method to pass data between the callbacks in a C module in FreeRADIUS?
For example, I want to create a unique request_id for the request and use it for all log entries during that request. If I create this value inside mod_authorize, how do I pass it over to mod_authenticate on the same request thread, and how do I retrieve it?
static rlm_rcode_t CC_HINT(nonnull) mod_authorize(void *instance, REQUEST *request)
{
// Generate uuid
uuid_t uuid;
uuid_generate_random(uuid);
// Convert to a string representation
char *request_id = talloc_array(mem_ctx, char, UUID_STR_LEN);
uuid_unparse(uuid, request_id);
// Do stuff and log authorize messages
radlog(L_INFO, "request_id inside mod_authorize: %s", request_id);
// How do I pass request_id to mod_authenticate callback
// ?????????????
return RLM_MODULE_OK;
}
static rlm_rcode_t CC_HINT(nonnull) mod_authenticate(void *instance, REQUEST *request)
{
char *request_id = NULL;
// How do I retrieve the request_id value
// ???????????????????
// Do stuff and log authenticate messages
radlog(L_INFO, "request_id inside mod_authenticate: %s", request_id);
return RLM_MODULE_OK;
}
Attaching the value to the request object seems like a logical thing, but I don't see a way of doing it, other than adding a value pair to the request->reply (and I don't want to return this value to NAS).
Thank you.
Apparently, there is a range of "Temporary attributes, for local storage" (defined in the dictionary.freeradius.internal file) that can be used with one of the requests object's collections (request->config, request->reply->vps and request->packet->vps). You can find the start of this range by searching dictionary.freeradius.internal file in the FreeRADIUS repository for
ATTRIBUTE Tmp-String-0
In this case I found request->packet->vps to be appropriate, and used Tmp-String-3 to add my request_id to it while inside MOD_AUTHORIZE callback:
pair_make_request("Tmp-String-3", request_ctx->request_id, T_OP_EQ);
where pair_make_request is a macro defined as
fr_pair_make(request->packet, &request->packet->vps, _a, _b, _c)
I then retrieved it, while inside MOD_AUTHENTICATE callback:
VALUE_PAIR *vp = fr_pair_find_by_num(request->packet->vps, PW_TMP_STRING_3, 0, TAG_ANY);
The numerical values of these attributes change between the versions, you must use macro definitions instead
The macros for these attributes, such as PW_TMP_STRING_3 in the esample above, are located in the file "attributes.h" which is auto-generated during the build. Here is a quote from Arran Cudbard-Bell, that I found here:
If you really want to know where each one is used, download,
configure, build the source. Then see src/include/attributes.h for the
macro versions, and grep -r through the code. That'll at least tell
you the modules, and if you're familiar with C you should be able to
figure out how/when they're added or checked for. – Arran Cudbard-Bell
Apr 12 '15 at 20:51
In my case, the resulting file is located at /usr/include/freeradius/attributes.h
I must say that it took me unreasonable amount of effort to track this information down. There is no other trace, none whatsoever, of these attribute macros. Not in the code, not in the FreeRADIUS documentation, not in Google search results.

Writing Clang AST Matchers

Is it possible to use the bind string on one expression in the other like the following code:
expr(declRefExpr().bind("id"), hasDesendent(declRefExpr(has("id")));
Basically to use bind id string of one node to find the other node.
The best way to compare 2 nodes is to bind in different id strings and then compare them in the callback method.
This is explained in this tutorial.
In the above link you can find the following code:
const VarDecl *IncVar = Result.Nodes.getNodeAs<VarDecl>("incVarName");
const VarDecl *CondVar = Result.Nodes.getNodeAs<VarDecl>("condVarName");
if (!areSameVariable(IncVar, CondVar))
return;
This code aims to compare nodes that are bind in variables incVarName and condVarName in the call back function.
Yes, it is possible using equalsBoundNode
Usage:
expr(declRefExpr().bind("id"), hasDesendent(declRefExpr(equalsBoundNode("id")));

how to to find a string in groovy list

question from a groovy newbie:
sql is initiated as follows
final Binding binding = new Binding();
binding.setProperty("sql", sql);
final groovy.sql.Sql sql = Sql.newInstance(dbConfig.getUrl(), dbConfig.getUserName(), dbConfig.getPasswd(),"oracle.jdbc.OracleDriver");
I am running a query in groovy like this
def listOfRows = sql.rows (select column1 from table1);
listOfRows when printed shows contents like [[column1_name:value1], [column1_name:value2], [column1_name:value3]]
I want to check if value2 (a String) exists in the returned list of values from the above query.
I have tried doing listOfRows.contains('value2') and listOfRows.find('value2'),
it complains that the method does not exist for lists..
what's the best way of doing this ?
EDITED: I have corrected the list of printed values. What's being returned is List<GroovyResultSet>
and I have also added the definition of sql.
I would suggest you to take a look at groovy documentation, and particularly to collections documentation (both tutorial and JDK/GDK).
in that case, the most specifically adapted solution would be to use Collection#find() ... with something like
listOfRows.find { it.contains(':value2') }
Which can be translated into human-readable
find the first element in this collection which string contains ":value2".
You probably want
listOfRows.column1.contains( 'value2' )
You are probably invoking this method which takes a GString (note that GString != String) as an argument. According to this question, a string in single quotes is a standard java string, and a string in double quotes is a templatable string.
'hello' //java.lang.String
"hello" //groovy.lang.GString
Try this:
listOfRows.contains("value2")
what i ended up doing is following :
iterate the listOfRows, get all the values for column1 from each GroovyResultSet into a listOfValues ,then check for my values in that list.
def listOfValues=[];
listOfRows.collect(listOfValues){it.getAt('column1')};
if(listOfValues.size()==3){
println('success');
}

Using the TYPE command inside a Redis / Lua Script

I am attempting to use the Redis TYPE command inside a Lua script (executed via EVAL)
local key_type = redis.call("TYPE", key)
According to the Redis documentation, this should return a string of "none", "zset" etc.
However the type of the returned value is a lua table. Comparing the value to a string always returns false.
I've managed to get around the problem by changing the call to
local key_type = redis.call("TYPE", key)["ok"]
This value is indeed a string and does work in string comparison commands. I am worried that this is a bug in my particular version of Redis and it will break in future versions when I upgrade.
Does anyone know if this is expected behaviour, or a bug?
The TYPE command returns a status reply (a.k.a simple string), e.g "+list\r\n".
On Redis scripting side, call is implemented by luaRedisCallCommand which performs the real Redis command behind the scenes.
Once successfully executed, this function converts the command result with redisProtocolToLuaType.
When a status reply is encountered, this function creates a Lua table with "ok" as key, and the status reply as value (see redisProtocolToLuaType_Status). So:
there is no bug,
this is why redis.call("TYPE", key) is a table (and thus you need to get the value for the "ok" key as you did, to get key's type as a string).
Note: when you directly return the table, Redis takes care to get the value associated to the "ok" key, and returns it as a status reply, e.g:
> EVAL 'return redis.call("TYPE", "foo")'
set
See this code section for more details.

Lua Error Attempt to perform arithmetic on local variable

Here is the function
calc.lua:
function foo(n)
return n*2
end
Here is my LuaJavaCall
L.getGlobal("foo");
L.pushJavaObject(8);
int retCode=L.pcall(1,1,0); // nResults)//L.pcall(1, 1,-2);
String errstr = L.toString(-1); // Attempt to perform arithmetic on local variable 'n'
Update: as indicated below I needed to use L.pushNumber(8.0) instead of L.pushJavaObject()
Try using L.pushNumber instead of L.pushJavaObject like this:
L.getGlobal("foo");
L.pushNumber(8.0);
int retCode = L.pcall(1,1,0);
String errstr = L.toString(-1);
Lua probably sees JavaObject as a type of 'userdata' in which case there are no predefined operations for it; Lua won't know what to do with a JavaObject * 2 since you didn't define how to handle it.
OTOH, Lua does know how to handle a number since that's a builtin primitive type. For the code snippet you presented, pushing a number would be the least painful way to get it working instead of writing extra code that tells Lua how to work with numbers wrapped inside a JavaObject.

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