I’m trying to seed data to phoenix database using json file.
Let’s say I have at priv/repo/seeds/some_file.json in my phoenix directory.
# priv/repo/seeds.exs
json_file = "#{__DIR__}/seeds/some_file.json"
with {:ok, body} <- File.read(json_file),
{:ok, json} <- Jason.decode(body, keys: :atom) do
# insert to db
else
err ->
IO.inspect(err)
end
But i got the following error when running the script :
(UndefinedFunctionError) function Jason.decode/2 is undefined (module Jason is not available)
I can see Jason dependency in my mix.exs file but it doesn’t seem to be working inside priv/repo/seeds.exs file. Or is there any other way / common patterns to seed phoenix app database from external file (json/csv) ?
Hi @dimitarvp, thanks for the reply.
I already ran mix deps.get and set keys: :atoms. But the same problem still occurs.
I also create another elixir module inside priv/ directory and it also cannot use Jason (same problem).
Here’s additional error message:
** (UndefinedFunctionError) function Jason.decode/2 is undefined (module Jason is not available)
Jason.decode("...long valid json body here...")
priv/repo/seeds.exs:21: (file)
(elixir 1.10.3) lib/code.ex:926: Code.require_file/2
But I can use the library just fine from lib/ directory.
At this point you should IMO just make a normal module inside your app – with an .ex file extensions – because such gymnastics with Code.require_file are brittle and you are just one dependency version away from that code breaking. But then it raises the question if you should have seeding code shipped with your production code (which I think you shouldn’t).
defmodule MyApp.MixProject do
use Mix.Project
def project do
[
app: :myapp,
version: "0.1.0",
elixir: "~> 1.7",
elixirc_paths: elixirc_paths(Mix.env()),
compilers: [:phoenix, :gettext] ++ Mix.compilers(),
start_permanent: Mix.env() == :prod,
aliases: aliases(),
deps: deps()
]
end
# Configuration for the OTP application.
#
# Type `mix help compile.app` for more information.
def application do
[
mod: {MyApp.Application, []},
extra_applications: [:logger, :runtime_tools]
]
end
# Specifies which paths to compile per environment.
defp elixirc_paths(:test), do: ["lib", "test/support"]
defp elixirc_paths(_), do: ["lib"]
# Specifies your project dependencies.
#
# Type `mix help deps` for examples and options.
defp deps do
[
{:bcrypt_elixir, "~> 2.0"},
{:phoenix, "~> 1.5.1"},
{:phoenix_ecto, "~> 4.1"},
{:ecto_sql, "~> 3.4"},
{:postgrex, ">= 0.0.0"},
{:phoenix_html, "~> 2.11"},
{:phoenix_live_reload, "~> 1.2", only: :dev},
{:phoenix_live_dashboard, "~> 0.2.0"},
{:telemetry_metrics, "~> 0.4"},
{:telemetry_poller, "~> 0.4"},
{:gettext, "~> 0.11"},
{:jason, "~> 1.0"},
{:plug_cowboy, "~> 2.0"},
{:phx_gen_auth, "~> 0.3.0", only: [:dev], runtime: false},
{:credo, "~> 1.4", only: [:dev, :test], runtime: false}
]
end
# Aliases are shortcuts or tasks specific to the current project.
# For example, to install project dependencies and perform other setup tasks, run:
#
# $ mix setup
#
# See the documentation for `Mix` for more info on aliases.
defp aliases do
[
setup: ["deps.get", "ecto.setup", "cmd npm install --prefix assets"],
"ecto.setup": ["ecto.create", "ecto.migrate", "run priv/repo/seeds.exs"],
"ecto.reset": ["ecto.drop", "ecto.setup"],
test: ["ecto.create --quiet", "ecto.migrate", "test"]
]
end
end
Yes, I agree about the hacky solution. But I also want my seeding scripts in the priv/ directory because IMO it doesn’t belong in lib/.
Usually, I create the data using simple elixir data structures or randomize data using loop in seeds.exs file. But I was wondering how’s the case when the seed data should came from json / csv file.
