I have Genserver which returns the data from the database. Now I want that data to store in a key-value manner in my Redis. But I’m not sure how to use this. I’m using this library https://github.com/whatyouhide/redix
defmodule Gorm.Database do
use GenServer
alias Gorm.Accounts
alias Gorm.Accounts.User
alias Gorm.Repo
def start_link(args) do
GenServer.start_link(__MODULE__, [])
end
def init(list) do
{:ok, []}
end
def list(pid) do
GenServer.call(pid, :list)
end
def handle_call(:list, _from, state) do
my_models = Accounts.list_users()
{:reply, my_models, state}
end
end
# alias Gorm.Database
# Gorm.Database
# iex(4)> Database.start_link([])
# {:ok, #PID<0.457.0>}
# iex(5)> {:ok, pid} = Database.start_link([])
# {:ok, #PID<0.459.0>}
# iex(6)> {:ok, pid} = Database.start_link([])
# {:ok, #PID<0.461.0>}
# iex(7)> pid
# #PID<0.461.0>
# iex(8)> Database.list(pid)
# [debug] QUERY OK source="users" db=16.6ms decode=3.0ms queue=22.2ms idle=9049.3ms
# SELECT u0."id", u0."email", u0."name", u0."inserted_at", u0."updated_at" FROM "users" AS u0 []
# [
# %Gorm.Accounts.User{
# __meta__: #Ecto.Schema.Metadata<:loaded, "users">,
# email: "ssaadamdkm@mfkmk.com",
# id: 1,
# inserted_at: ~N[2020-02-18 18:29:26],
# name: "siddhantsingh",
# updated_at: ~N[2020-02-18 18:29:26]
# }
# ]
# iex(9)>
Because right now in start_link function which takes list as a argument. Basically I’m confused about start link function what arguments and how do I call this?
Yes But I want to know how I can implement it. Because that I have implemented with Supervisor and this one is with genserver.
defmodule Gorm.RedisPool do
use Supervisor
@redis_connection_params host: Application.get_env(:gorm, :redis_host),
password: Application.get_env(:gorm, :redis_password),
port: Application.get_env(:gorm, :redis_port),
database: Application.get_env(:gorm, :redis_database)
def start_link(_args) do
Supervisor.start_link(__MODULE__, [])
end
#Fault Tolerance
# This is just ensuring that phoenix keeps the cache running.
def init([]) do
pool_opts = [
name: {:local, :redix_poolboy},
worker_module: Redix,
size: 10,
max_overflow: 5,
]
children = [
:poolboy.child_spec(:redix_poolboy, pool_opts, @redis_connection_params)
]
Supervisor.init(children, strategy: :one_for_one, name: __MODULE__)
end
def command(command) do
:poolboy.transaction(:redix_poolboy, &Redix.command(&1, command))
end
def pipeline(commands) do
:poolboy.transaction(:redix_poolboy, &Redix.pipeline(&1, commands))
end
end
Look
defmodule Gorm.Database do
use GenServer
alias Gorm.Accounts
alias Gorm.Accounts.User
alias Gorm.Repo
def start_link(args) do
GenServer.start_link(__MODULE__, [])
end
def init(list) do
{:ok, []}
end
def list(pid) do
GenServer.call(pid, :list)
end
def handle_call(:list, _from, state) do
my_models = Accounts.list_users()
{:reply, my_models, state}
end
end
defmodule Gorm.Database do
use GenServer
alias Gorm.Accounts
alias Gorm.Accounts.User
alias Gorm.Repo
def start_link(args) do
GenServer.start_link(__MODULE__, [])
end
def init(list) do
{:ok, []}
end
def list(pid) do
GenServer.call(pid, :list)
end
def get(:list, key) do
Genserver.call(list, {:get, key})
end
def set(:list, key, value) do
GenServer.call(list, {:set, key, value})
end
def handle_call(:list, _from, state) do
my_models = Accounts.list_users()
{:reply, my_models, state}
end
end
defmodule Gorm.Database do
use GenServer
alias Gorm.Accounts
alias Gorm.Accounts.User
alias Gorm.Repo
def start_link(args) do
GenServer.start_link(__MODULE__, [])
end
def init(list) do
{:ok, []}
end
def list(pid) do
GenServer.call(pid, :list)
end
def get(pid, key) do
GenServer.call(pid, {:get, key})
end
def set(pid, key, value) do
GenServer.call(pid, {:set, key, value})
end
def handle_call(:list, _from, state) do
my_models = Accounts.list_users()
{:reply, my_models, state}
end
end
But we are not asking for that. We are asking what are you trying to do exactly. By saying “to implement GenServer and Redis” you tell us exactly nothing.
EDIT: What I mean is you should have answered with “I am trying to have my app supervise the connection to Redis and to read and write basic data to it”. This is a potential answer for us with which we can help you.
It’s difficult to get started, as lots of things don’t make sense. But you need to give yourself time and understand the fundamentals first, then you will be able to build up from there. I am sorry but it’s not really possible to help you out with this, because we don’t know what you want to achieve, and which problems you are encountering.
My honest suggestion would be to take a step back, and tackle one thing at a time. It looks like you know Elixir basics, so you can move from there. You can then tackle OTP, and focus on smaller problems until you understand GenServers and such. Then you’ll be ready to move on to using them for stuff like Redis or databases.
As you learn, should you hit something specific that you don’t understand or that you cannot fix, you will be able to explain your specific problem, and lots of people here can help you with that. But you’ll need to specify well what you are trying to do, and where you hit problems.
We all went through this, and we all asked naive questions and got help from more experienced people, so do not feel ashamed to ask. But you cannot expect people to write your code for you from scratch.
