REDIS NoSQL Database - Consumed in Python
docker run -d --cap-add sys_resource --name rp -p 8443:8443 -p 9443:9443 -p 12000:12000 redislabs/redis
Next, go to https://localhost:8443 and configure redis, you can follow the redis developer guide located at https://developer.redis.com/operate/orchestration/docker/.
After configured, you can access the redis-cli, for this, run the command below:
docker exec -it rp bash
Next...
/opt/redislabs/bin/redis-cli -p {database_port}
In my case, database port is 13300, you can see it in database settings.
Then, you need to authenticate with database password:
auth {password}
Wow, now you can use / consume redis, beautiful...
If you want, you can use docker-compose.yml file to run docker and docker-commander, but, for this, you need configure .env file and specify REDIS_PASSWORD, REDIS_COMMANDER_USER and REDIS_COMMANDER_PASS. I prefere this way, its more simple and more flexible.
Just run:
docker-compose up -d
or, if you want see logs:
docker-compose up
Now, you can check if always created successfully. You can access http://127.0.0.1:8081/ an try login, or, access redis-cli, for this:
docker exec -it redis redis-cli
and then, try login typing:
auth {REDIS_PASSWORD}
from dotenv import load_dotenv
from redis import Redis
import os
load_dotenv('.env', verbose=True)
HOST: str = os.environ.get('REDIS_HOST')
PORT: int = int(os.environ.get('REDIS_PORT'))
PASSWORD: str = os.environ.get('REDIS_PASSWORD')
def connection() -> Redis:
return Redis(
host=HOST,
port=PORT,
db=0,
password=PASSWORD,
charset='utf-8',
decode_responses=True
)
def main(conn: Redis):
if not conn.ping():
raise "Connection error while trying to ping"
if __name__ == '__main__':
conn: Redis = connection()
main(conn)In the code example i import Redis, of course, to stabilish a connection with the database, dotenv to load .env file and os to get environment variables.
Next, create Redis instance and pass to the constructor function env vars, like host, port and password, and pass either, database, default Redis db is 0, pass charset and decode_responses.
Then, in main function i check if connection can be created, raising exception if not.
SET and GET:
set: Set a value. Return boolean.
conn.set(3, "DESIGNER")get: Get a value.
print(conn.get("3"))getset: Set new value and return old string value
print(conn.getset(2, "Engenheiro de dados"))Multiple Values - SET:
mset: Set multiple values, pass dictionary / key - value. Return boolean.
many = {
1: "Engenheiro de dados",
2: "Engenheiro de software"
}
conn.mset(many)Multiple Values - GET:
mget: Get multiple values, just pass all keys that you intend get. Return list with all values, None if value does not exist.
print(conn.mget(2, 3, 1))exists: Check if a value exists. Return boolean.
print(conn.exists(1))delete: Delete a value. Return 1 (if deleted) or 0.
conn.delete(1)type: Return type of value.
print(conn.type(2))Expiration - SET:
expire: Set in how many seconds the value will expire. Return boolean.
conn.expire(3, 60)pexpire: Set in how many milliseconds the value will expire. Return boolean.
conn.pexpire(2, 5000)Expiration - GET:
ttl: Get how many seconds left until the value expires
print(conn.ttl(3))pttl: Get how many milliseconds left until the value expires
print(conn.pttl(2))persist: Calcel expiration time, and persist the value in memory. Return boolean.
conn.persist(2)getrange: Get value range, you specify the string key and next start and end range, same range in python / other programming languages.
print(conn.getrange(2, 0, 9))strlen: Get value length
print(conn.strlen(2))SET and GET:
hset: Set hash. You can pass a dictionary or just key, value. Returns the number of fields that were added.
Example with dictionary:
conn.hset(name="register", mapping={
"name": "Josef",
"years": 29,
"email": "josef@gmail.com",
"city": "San Francisco"
})Example with just key, value:
conn.hset(
name="address",
key="city",
value="San Francisco"
)hgetall: Return a Python dict of the hash's name / value pairs.
print(conn.hgetall("register"))hmget: Get specific fields from hash. Returns a list. In the example bellow, return just name and email values.
print(conn.hmget("register", "name", "email"))hvals: Get all values from hash. Returns a list.
print(conn.hvals("register"))hexists: Check if a field exists in hash. Return a boolean.
print(conn.hexists("register", "name"))hkeys: Get all keys from hash. Returns a list.
print(conn.hkeys("register"))hlen: Return the number of elements in hash.
print(conn.hlen("register"))hdel: Delete key / keys from hash. Return number of keys been deleted.
print(conn.hdel("register", "city"))Insertion:
lpush: Insert / push a value into the head of the list. Create list if not exists. Return list length.
print(conn.lpush(44, "MySQL", "Oracle", "PostgreSQL", "SQL Server"))rpush: Insert / push a value into the tail of the list. Create list if not exists. Return list length.
print(conn.rpush(44, "DB2"))linsert: Insert after / before specific value. Returns the new length of the list on success or -1 if refvalue is not in the list.
print(conn.linsert(44, where="AFTER", refvalue="Oracle", value="Firebird"))print(conn.linsert(44, where="BEFORE", refvalue="Firebird", value="SQLite"))lrange: Get range of values from the list. Return list with values.
print(conn.lrange(44, 0, 3))lset: Update list value, you need pass the index to the value that you will update and new value. Return bool.
print(conn.lset(44, index=1, value="OtherDB"))lindex: Get list value by index.
print(conn.lindex(name=44, index=1))llen: Return list length.
print(conn.llen(name=44))Removing values from the list:
lpop: Remove first value from the list. Return value deleted.
print(conn.lpop(name=44))rpop: Remove last value from the list. Return value deleted.
print(conn.rpop(name=44))Unordered sets:
sadd: Add value / values to the set, create it if doesn't exist. Return number of elements added to the set.
If you add a existing value, return 0, doesn`t add it to the set.
print(conn.sadd(55, "Hadoop", "Spark", "Hive", "Pig"))smembers: Get all set members. Return Python set data object.
print(conn.smembers(name=55))scard: Return set length.
print(conn.scard(name=55))sismember: Ckeck if a value is member / is in the set. Return bool.
print(conn.sismember(name=55, value="Spark"))srem: Remove a value / or values from the set. Return number of removed values.
print(conn.srem(55, "Spark"))Unordered Sets operations:
sdiff: Return set with differences between two sets. Note that in the code below i`m checking the difference from the set with key 55 to the set with key 56.
print(conn.sdiff(55, 56))Next, i`m check the difference from the set with key 56 to the set with key 55.
print(conn.sdiff(56, 55))sinter: Check sets intersection. Return set.
print(conn.sinter(55, 56))Ordered Sets:
zadd: Add value / values with score in the set, create it if doesn't exist.
Return number of elements added to the set.
print(conn.zadd(name=64, mapping={
"Hadoop": 0,
"Solr": 1,
"Hive": 2,
"Flume": 3,
}))zcard: Return number of set elements.
print(conn.zcard(name=64))zrank: Get index of a set element. If you pass withscore=True return a list with the index and the score, by default withscore is equal False.
print(conn.zrank(name=64, value="Solr"))zcount: Count how many elements i have between two numbers, min and max.
print(conn.zcount(name=64, min=0, max=3))zscore: Get score for set element. Return a float.
print(conn.zscore(name=64, value="Solr"))zrange: Return a list with set members by index, start and end. You can specify order, withscores, and more items.
print(conn.zrange(name=64, start=0, end=3))zrem: Remove an element or many elements from the set. Return number of elements removed.
print(conn.zrem(name=64, values="Solr"))