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cluster.ex
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defmodule Pleroma.Cluster do
@moduledoc """
Facilities for managing a cluster of slave VM's for federated testing.
## Spawning the federated cluster
`spawn_cluster/1` spawns a map of slave nodes that are started
within the running VM. During startup, the slave node is sent all configuration
from the parent node, as well as all code. After receiving configuration and
code, the slave then starts all applications currently running on the parent.
The configuration passed to `spawn_cluster/1` overrides any parent application
configuration for the provided OTP app and key. This is useful for customizing
the Ecto database, Phoenix webserver ports, etc.
For example, to start a single federated VM named ":federated1", with the
Pleroma Endpoint running on port 4123, and with a database named
"pleroma_test1", you would run:
endpoint_conf = Application.fetch_env!(:pleroma, Pleroma.Web.Endpoint)
repo_conf = Application.fetch_env!(:pleroma, Pleroma.Repo)
Pleroma.Cluster.spawn_cluster(%{
:"federated1@127.0.0.1" => [
{:pleroma, Pleroma.Repo, Keyword.merge(repo_conf, database: "pleroma_test1")},
{:pleroma, Pleroma.Web.Endpoint,
Keyword.merge(endpoint_conf, http: [port: 4011], url: [port: 4011], server: true)}
]
})
*Note*: application configuration for a given key is not merged,
so any customization requires first fetching the existing values
and merging yourself by providing the merged configuration,
such as above with the endpoint config and repo config.
## Executing code within a remote node
Use the `within/2` macro to execute code within the context of a remote
federated node. The code block captures all local variable bindings from
the parent's context and returns the result of the expression after executing
it on the remote node. For example:
import Pleroma.Cluster
parent_value = 123
result =
within :"federated1@127.0.0.1" do
{node(), parent_value}
end
assert result == {:"federated1@127.0.0.1, 123}
*Note*: while local bindings are captured and available within the block,
other parent contexts like required, aliased, or imported modules are not
in scope. Those will need to be reimported/aliases/required within the block
as `within/2` is a remote procedure call.
"""
@extra_apps Pleroma.Mixfile.application()[:extra_applications]
@doc """
Spawns the default Pleroma federated cluster.
Values before may be customized as needed for the test suite.
"""
def spawn_default_cluster do
endpoint_conf = Application.fetch_env!(:pleroma, Pleroma.Web.Endpoint)
repo_conf = Application.fetch_env!(:pleroma, Pleroma.Repo)
spawn_cluster(%{
:"federated1@127.0.0.1" => [
{:pleroma, Pleroma.Repo, Keyword.merge(repo_conf, database: "pleroma_test_federated1")},
{:pleroma, Pleroma.Web.Endpoint,
Keyword.merge(endpoint_conf, http: [port: 4011], url: [port: 4011], server: true)}
],
:"federated2@127.0.0.1" => [
{:pleroma, Pleroma.Repo, Keyword.merge(repo_conf, database: "pleroma_test_federated2")},
{:pleroma, Pleroma.Web.Endpoint,
Keyword.merge(endpoint_conf, http: [port: 4012], url: [port: 4012], server: true)}
]
})
end
@doc """
Spawns a configured map of federated nodes.
See `Pleroma.Cluster` module documentation for details.
"""
def spawn_cluster(node_configs) do
# Turn node into a distributed node with the given long name
:net_kernel.start([:"primary@127.0.0.1"])
# Allow spawned nodes to fetch all code from this node
{:ok, _} = :erl_boot_server.start([])
allow_boot("127.0.0.1")
silence_logger_warnings(fn ->
node_configs
|> Enum.map(&Task.async(fn -> start_slave(&1) end))
|> Enum.map(&Task.await(&1, 90_000))
end)
end
@doc """
Executes block of code again remote node.
See `Pleroma.Cluster` module documentation for details.
"""
defmacro within(node, do: block) do
quote do
rpc(unquote(node), unquote(__MODULE__), :eval_quoted, [
unquote(Macro.escape(block)),
binding()
])
end
end
@doc false
def eval_quoted(block, binding) do
{result, _binding} = Code.eval_quoted(block, binding, __ENV__)
result
end
defp start_slave({node_host, override_configs}) do
log(node_host, "booting federated VM")
{:ok, node} = :slave.start(~c"127.0.0.1", node_name(node_host), vm_args())
add_code_paths(node)
load_apps_and_transfer_configuration(node, override_configs)
ensure_apps_started(node)
{:ok, node}
end
def rpc(node, module, function, args) do
:rpc.block_call(node, module, function, args)
end
defp vm_args do
~c"-loader inet -hosts 127.0.0.1 -setcookie #{:erlang.get_cookie()}"
end
defp allow_boot(host) do
{:ok, ipv4} = :inet.parse_ipv4_address(~c"#{host}")
:ok = :erl_boot_server.add_slave(ipv4)
end
defp add_code_paths(node) do
rpc(node, :code, :add_paths, [:code.get_path()])
end
defp load_apps_and_transfer_configuration(node, override_configs) do
Enum.each(Application.loaded_applications(), fn {app_name, _, _} ->
app_name
|> Application.get_all_env()
|> Enum.each(fn {key, primary_config} ->
rpc(node, Application, :put_env, [app_name, key, primary_config, [persistent: true]])
end)
end)
Enum.each(override_configs, fn {app_name, key, val} ->
rpc(node, Application, :put_env, [app_name, key, val, [persistent: true]])
end)
end
defp log(node, msg), do: IO.puts("[#{node}] #{msg}")
defp ensure_apps_started(node) do
loaded_names = Enum.map(Application.loaded_applications(), fn {name, _, _} -> name end)
app_names = @extra_apps ++ (loaded_names -- @extra_apps)
rpc(node, Application, :ensure_all_started, [:mix])
rpc(node, Mix, :env, [Mix.env()])
rpc(node, __MODULE__, :prepare_database, [])
log(node, "starting application")
Enum.reduce(app_names, MapSet.new(), fn app, loaded ->
if Enum.member?(loaded, app) do
loaded
else
{:ok, started} = rpc(node, Application, :ensure_all_started, [app])
MapSet.union(loaded, MapSet.new(started))
end
end)
end
@doc false
def prepare_database do
log(node(), "preparing database")
repo_config = Application.get_env(:pleroma, Pleroma.Repo)
repo_config[:adapter].storage_down(repo_config)
repo_config[:adapter].storage_up(repo_config)
{:ok, _, _} =
Ecto.Migrator.with_repo(Pleroma.Repo, fn repo ->
Ecto.Migrator.run(repo, :up, log: false, all: true)
end)
Ecto.Adapters.SQL.Sandbox.mode(Pleroma.Repo, :manual)
{:ok, _} = Application.ensure_all_started(:ex_machina)
end
defp silence_logger_warnings(func) do
prev_level = Logger.level()
Logger.configure(level: :error)
res = func.()
Logger.configure(level: prev_level)
res
end
defp node_name(node_host) do
node_host
|> to_string()
|> String.split("@")
|> Enum.at(0)
|> String.to_atom()
end
end

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