I am using Redisson for Redis. I have installed Redis on my local system. I've written the following code and ran it:
Config config = new Config();
config.useSingleServer()
.setAddress("redis://127.0.0.1:6379");
RedissonClient client = Redisson.create(config);
RMap<String, RList<String>> settings = client.getMap("settings");
RList<String> options1 = client.getList("settings_server1_option");
options1.add("Hello");
options1.add("World");
settings.put("server1", options1);
RList<String> options2 = client.getList("settings_server2_option");
options2.add("My land");
options2.add("Your land");
settings.put("server2", options2);
RList<String> options2Value = settings.get("server2");
System.out.println(options2Value);
I get the value that is expected, however, when I go into redis-cli and try to retrieve that key, I get nil why is that? Why is it not pushing the data into Redis?
You can just connect to redis-cli and run monitor command and then execute your code. If yuou are connected to the correct redis server, the command will be shown on redis-cli. If it doesn't appear then probably you are connected to the wrong server.
You can run client list on redis-cli to see number of connected clients and their address.
Related
In django application I need to call an external rabbitmq, running on a windows server and using some application there, where the django app runs on a linux server.
I'm currently able to add a task to the queue by using the celery send_task:
app.send_task('tasks', kwargs=self.get_input(), queue=Queue('queue_async', durable=False))
My settings looks like:
CELERY_BROKER_URL = CELERY_CONFIG['broker_url']
BROKER_TRANSPORT_OPTIONS = {"max_retries": 3, "interval_start": 0, "interval_step": 0.2, "interval_max": 0.5}
CELERY_ACCEPT_CONTENT = ['application/json']
CELERY_TASK_SERIALIZER = 'json'
CELERY_RESULT_SERIALIZER = 'json'
CELERY_TASK_DEFAULT_QUEUE = 'celery'
CELERY_TASK_RESULT_EXPIRES = 3600
CELERY_RESULT_BACKEND = 'rpc://'
CELERY_CREATE_MISSING_QUEUES = True
What I'm not sure about is how I can get and parse the response, since the send_task only returns a key?
If you want to store results of your task , you could use this parameter result_backend or CELERY_RESULT_BACKEND depending on the version of celery you're using.
Complete list of Configuration options can be found here (search for result_backend on this page) => https://docs.celeryproject.org/en/stable/userguide/configuration.html
Many options are available to store results - SQL DBs , NoSQL DBs, Elasticsearch, Memcache, Redis, etc,etc . Choose as per your project stack.
Thanks that helped for the understanding. So since I want to further process the answer I use rpc as already defined in the config I had in the example.
What I found usefull was this example, because most python celery examples assume that the consumer is the same application, that describes the interaction to a Java app Celery-Java since it gives a good example on how to request from python side.
Therefore my implementation is now:
result = app.signature('tasks', kwargs=self.get_input(), queue=Queue('queue_async', durable=False)).delay().get()
which waits and parses the result.
my aim is to add only slaves URIs, because master is not available in my case. But lettuce library returns
io.lettuce.core.RedisException: Master is currently unknown: [RedisMasterSlaveNode [redisURI=RedisURI [host='127.0.0.1', port=6382], role=SLAVE], RedisMasterSlaveNode [redisURI=RedisURI [host='127.0.0.1', port=6381], role=SLAVE]]
So the question is: Is it possible so avoid this exception somehow? Maybe configuration. Thank you in advance
UPDATE: Forgot to say that after borrowing object from pool I set connection.readFrom(ReadFrom.SLAVE) before running commands.
GenericObjectPoolConfig config = fromRedisConfig(properties);
List<RedisURI> nodes = new ArrayList<>(properties.getUrl().length);
for (String url : properties.getUrl()) {
nodes.add(RedisURI.create(url));
}
return ConnectionPoolSupport.createGenericObjectPool(
() -> MasterSlave.connect(redisClient, new ByteArrayCodec(), nodes), config);
The problem was that I tried to set data, which is possible only with master node. So there is no problem with MasterSlave. Get data works perfectly
I have just installed hubot and I'm trying some basic tests.
I have this basic script in /scripts:
module.exports = (robot) ->
robot.respond /myscript status/i, (msg) ->
if robot.auth.hasRole(msg.envelope.user, 'test')
msg.reply "Success"
else
msg.reply "Sorry. Need 'test' role."
I issue the appropriate Slack commands:
schroeder has test role
"OK, schroeder has the 'test' role."
myscript status
"Sorry. Need 'test' role."
I have:
tried to reverse the logic (if vs unless)
verified that the scripts are being updated (by changing responses)
verified that the redis backend is storing the role (connected via redis-cli and inspected the key).
After re-reading all the documentation and looking up bug reports I still cannot see what I'm missing. It has got to be something simple, but I'm out of ideas. It is almost as though the script is not able to view the stored role (hubot-auth can, but my script cannot).
Even though on start, hubot says that it is connecting to a local Redis server:
INFO hubot-redis-brain: Using default redis on localhost:6379
It isn't... At least not in a way that you would expect.
If redis is, in fact running, you should get an extra message:
INFO hubot-redis-brain: Data for hubot brain retrieved from Redis
That message does not appear and there is no warning or error that Redis is not running.
If you have not set up hubot-redis-brain properly, you will get strange errors and inconsistencies, like hubot-auth role check functions failing.
In addition, I found that even after I set Redis up properly, my test script did not work. Even though all the tutorials I found test the msg.envelope.user, this did not work for me. I needed to use the msg.message.user.name and resolve with the brain class:
module.exports = (robot) ->
robot.respond /fbctf status/i, (msg) ->
user = robot.brain.userForName(msg.message.user.name)
if robot.auth.hasRole(user, 'test')
msg.reply "Success"
else
msg.reply "Sorry. Need 'test' role."
I'm new to Redis and trying to figure out a simple way to use Redis as a local cache for my C# app. I've downloaded and ran the redis-server from https://github.com/MSOpenTech/redis/releases
I can successfully store a key value and retrieve it as follows:
var redisManager = new PooledRedisClientManager("localhost:6379");
using (var redis = redisManager.GetClient())
{
redis.Set("mykey_1", 15, TimeSpan.FromSeconds(3600));
// get typed value from cache
int valueFromCache = redis.Get<int>("mykey_1"); // must be =
}
I want to limit the amount of memory Redis uses on my server and I also want redis to automatically purge values when memory fills. I tried the maxmemory command but in the redus-cli program maxmemory is not found.
Will Redus automatically purge old values for me? (I assume not) and if not, is there a way that I can make the default behavior of redis do that with the Set method I'm using below?
If I'm heading down the wrong path, please let me know.
The answer to your question is described here: What does Redis do when it runs out of memory?
Basically, you set the maxmemory from the config file, and not from the redis-cli. You can also specify a maxmemory-policy, which is a set of procedures that redis executes when it runs out of the specified memory. According to that config file, there are a total of 6 policies that Redis is using when it runs out of memory:
volatile-lru -> remove the key with an expire set using an LRU algorithm
allkeys-lru -> remove any key according to the LRU algorithm
volatile-random -> remove a random key with an expire set
allkeys-random -> remove a random key, any key
volatile-ttl -> remove the key with the nearest expire time (minor TTL)
noeviction -> don't expire at all, just return an error on write operations
You can set those behaviours using the maxmemory-policy directive that you find in the LIMITS section of redis.conf file (above the maxmemory directive).
So, you can set an expire time to every key that you store in Redis (a large expire time) and also set a volatile-ttl policy. In that way, when Redis runs out of memory, the key with the smallest TTL (which is also the oldest one) is removed, according to the policy that you've set.
When trying to run the following in Redis using booksleeve.
using (var conn = new RedisConnection(server, port, -1, password))
{
var result = conn.Server.FlushDb(0);
result.Wait();
}
I get an error saying:
This command is not available unless the connection is created with
admin-commands enabled"
I am not sure how do i execute commands as admin? Do I need to create an a/c in db with admin access and login with that?
Updated answer for StackExchange.Redis:
var conn = ConnectionMultiplexer.Connect("localhost,allowAdmin=true");
Note also that the object created here should be created once per application and shared as a global singleton, per Marc:
Because the ConnectionMultiplexer does a lot, it is designed to be
shared and reused between callers. You should not create a
ConnectionMultiplexer per operation. It is fully thread-safe and ready
for this usage.
Basically, the dangerous commands that you don't need in routine operations, but which can cause lots of problems if used inappropriately (i.e. the equivalent of drop database in tsql, since your example is FlushDb) are protected by a "yes, I meant to do that..." flag:
using (var conn = new RedisConnection(server, port, -1, password,
allowAdmin: true)) <==== here
I will improve the error message to make this very clear and explicit.
You can also set this in C# when you're creating your multiplexer - set AllowAdmin = true
private ConnectionMultiplexer GetConnectionMultiplexer()
{
var options = ConfigurationOptions.Parse("localhost:6379");
options.ConnectRetry = 5;
options.AllowAdmin = true;
return ConnectionMultiplexer.Connect(options);
}
For those who like me faced the error:
StackExchange.Redis.RedisCommandException: This operation is not
available unless admin mode is enabled: ROLE
after upgrading StackExchange.Redis to version 2.2.4 with Sentinel connection: it's a known bug, the workaround was either to downgrade the client back or to add allowAdmin=true to the connection string and wait for the fix.
Starting from 2.2.50 public release the issue is fixed.