Behaviour for pluggable session storage backends.

ConduitMCP uses sessions to track MCP protocol state per client connection. The default implementation uses ETS (ConduitMcp.Session.EtsStore), but you can implement this behaviour for any storage backend.

Implementing a Custom Store

Redis Example

defmodule MyApp.RedisSessionStore do
  @behaviour ConduitMcp.Session.Store

  @impl true
  def create(session_id, metadata) do
    data = JSON.encode!(metadata)
    Redix.command(:redix, ["SET", key(session_id), data, "EX", "3600"])
    :ok
  end

  @impl true
  def get(session_id) do
    case Redix.command(:redix, ["GET", key(session_id)]) do
      {:ok, nil} -> {:error, :not_found}
      {:ok, data} -> {:ok, JSON.decode!(data)}
    end
  end

  @impl true
  def delete(session_id) do
    Redix.command(:redix, ["DEL", key(session_id)])
    :ok
  end

  @impl true
  def update(session_id, metadata) do
    case get(session_id) do
      {:ok, existing} ->
        create(session_id, Map.merge(existing, metadata))
      {:error, :not_found} ->
        {:error, :not_found}
    end
  end

  defp key(session_id), do: "mcp:session:#{session_id}"
end

Mnesia Example (Distributed Erlang)

defmodule MyApp.MnesiaSessionStore do
  @behaviour ConduitMcp.Session.Store
  # Uses Mnesia for distributed session replication across nodes
  # Ideal for clustered deployments
end

Configuration

# Default (ETS, zero config)
{ConduitMcp.Transport.StreamableHTTP,
  server_module: MyServer,
  session: [store: ConduitMcp.Session.EtsStore]}

# Custom store with TTL
{ConduitMcp.Transport.StreamableHTTP,
  server_module: MyServer,
  session: [store: MyApp.RedisSessionStore, ttl: :timer.minutes(60)]}

# Disable sessions entirely
{ConduitMcp.Transport.StreamableHTTP,
  server_module: MyServer,
  session: false}