Foundation.Distributed - Partisan-Powered Distribution Layer

lib/foundation/distributed.ex

defmodule Foundation.Distributed do @moduledoc """ Foundation 2.0 Distributed Layer powered by Partisan

Provides revolutionary clustering capabilities:

• Multi-channel communication
• Dynamic topology switching
• Intelligent service discovery
• Partition-tolerant coordination """

def available?() do Application.get_env(:foundation, :distributed, false) and Code.ensure_loaded?(:partisan) end

defdelegate switch_topology(topology), to: Foundation.Distributed.Topology defdelegate send_message(channel, destination, message), to: Foundation.Distributed.Channels defdelegate discover_services(criteria), to: Foundation.Distributed.Discovery defdelegate coordinate_consensus(proposal), to: Foundation.Distributed.Consensus end

Foundation.Distributed.Topology - Dynamic Network Management

lib/foundation/distributed/topology.ex

defmodule Foundation.Distributed.Topology do @moduledoc """ Dynamic topology management with Partisan overlays.

Automatically selects and switches between optimal topologies based on cluster size, workload patterns, and network conditions. """

use GenServer require Logger

defstruct [ :current_topology, :overlay_config, :performance_metrics, :topology_history, :switch_cooldown ]

Public API

@doc """ Switches the cluster topology at runtime.

Supported Topologies:

• :full_mesh - Every node connected to every other (best for <10 nodes)
• :hyparview - Peer sampling with partial views (best for 10-1000 nodes)
• :client_server - Hierarchical with designated servers (best for >1000 nodes)
• :pub_sub - Event-driven with message brokers (best for event systems) """ def switch_topology(new_topology) do GenServer.call(MODULE, {:switch_topology, new_topology}) end

@doc """ Optimizes topology for specific workload patterns. """ def optimize_for_workload(workload_type) do GenServer.call(MODULE, {:optimize_for_workload, workload_type}) end

@doc """ Gets current topology information. """ def current_topology() do GenServer.call(MODULE, :get_current_topology) end

@doc """ Monitors topology performance and suggests optimizations. """ def analyze_performance() do GenServer.call(MODULE, :analyze_performance) end

GenServer Implementation

def start_link(opts \ []) do GenServer.start_link(MODULE, opts, name: MODULE) end

@impl true def init(opts) do initial_topology = Keyword.get(opts, :initial_topology, :full_mesh)

state = %__MODULE__{
  current_topology: initial_topology,
  overlay_config: initialize_overlay_config(),
  performance_metrics: %{},
  topology_history: [],
  switch_cooldown: 30_000  # 30 seconds minimum between switches
}

# Initialize Partisan with initial topology
initialize_partisan_topology(initial_topology)

# Start performance monitoring
schedule_performance_monitoring()

{:ok, state}

end

@impl true def handle_call({:switch_topology, new_topology}, _from, state) do case can_switch_topology?(state) do true -> case perform_topology_switch(new_topology, state) do {:ok, new_state} -> Logger.info(“Successfully switched topology from #{state.current_topology} to #{new_topology}”) {:reply, :ok, new_state} {:error, reason} -> Logger.error(“Failed to switch topology: #{reason}”) {:reply, {:error, reason}, state} end false -> {:reply, {:error, :switch_cooldown_active}, state} end end

@impl true def handle_call({:optimize_for_workload, workload_type}, _from, state) do optimal_topology = determine_optimal_topology(workload_type, state)

if optimal_topology != state.current_topology do
  case perform_topology_switch(optimal_topology, state) do
    {:ok, new_state} ->
      Logger.info("Optimized topology for #{workload_type}: #{optimal_topology}")
      {:reply, {:ok, optimal_topology}, new_state}
    {:error, reason} ->
      {:reply, {:error, reason}, state}
  end
else
  {:reply, {:already_optimal, optimal_topology}, state}
end

end

@impl true def handle_call(:get_current_topology, _from, state) do topology_info = %{ current: state.current_topology, node_count: get_cluster_size(), performance: get_current_performance_metrics(), last_switch: get_last_switch_time(state) }

{:reply, topology_info, state}

end

@impl true def handle_call(:analyze_performance, _from, state) do analysis = analyze_topology_performance(state) {:reply, analysis, state} end

@impl true def handle_info(:monitor_performance, state) do new_metrics = collect_performance_metrics() new_state = %{state | performance_metrics: new_metrics}

# Check if topology optimization is needed
case should_auto_optimize?(new_state) do
  {:yes, recommended_topology} ->
    Logger.info("Auto-optimization recommends switching to #{recommended_topology}")
    case perform_topology_switch(recommended_topology, new_state) do
      {:ok, optimized_state} ->
        schedule_performance_monitoring()
        {:noreply, optimized_state}
      {:error, reason} ->
        Logger.warning("Auto-optimization failed: #{reason}")
        schedule_performance_monitoring()
        {:noreply, new_state}
    end
  :no ->
    schedule_performance_monitoring()
    {:noreply, new_state}
end

end

Topology Management Implementation

defp initialize_partisan_topology(topology) do overlay_config = get_overlay_config_for_topology(topology)

case Application.get_env(:partisan, :overlay, nil) do
  nil ->
    Application.put_env(:partisan, :overlay, overlay_config)
    Logger.info("Initialized Partisan with #{topology} topology")
  _ ->
    Logger.info("Partisan already configured, updating overlay")
end

end

defp get_overlay_config_for_topology(:full_mesh) do [{:overlay, :full_mesh, %{channels: [:coordination, :data]}}] end

defp get_overlay_config_for_topology(:hyparview) do [{:overlay, :hyparview, %{ channels: [:coordination, :data, :gossip], active_view_size: 6, passive_view_size: 30, arwl: 6 }}] end

defp get_overlay_config_for_topology(:client_server) do [{:overlay, :client_server, %{ channels: [:coordination, :data], server_selection_strategy: :round_robin }}] end

defp get_overlay_config_for_topology(:pub_sub) do [{:overlay, :plumtree, %{ channels: [:events, :coordination], fanout: 5, lazy_push_probability: 0.25 }}] end

defp perform_topology_switch(new_topology, state) do old_topology = state.current_topology

try do
  # Prepare new overlay configuration
  new_overlay_config = get_overlay_config_for_topology(new_topology)
  
  # Perform graceful transition
  case graceful_topology_transition(old_topology, new_topology, new_overlay_config) do
    :ok ->
      new_state = %{state |
        current_topology: new_topology,
        overlay_config: new_overlay_config,
        topology_history: [
          %{
            from: old_topology,
            to: new_topology,
            timestamp: :os.system_time(:millisecond),
            reason: :manual_switch
          } | state.topology_history
        ]
      }
      
      {:ok, new_state}
    
    {:error, reason} ->
      {:error, reason}
  end
rescue
  error ->
    Logger.error("Topology switch error: #{inspect(error)}")
    {:error, {:switch_failed, error}}
end

end

defp graceful_topology_transition(old_topology, new_topology, new_config) do Logger.info(“Starting graceful transition from #{old_topology} to #{new_topology}”)

# Step 1: Announce topology change to cluster
announce_topology_change(new_topology)

# Step 2: Update configuration
Application.put_env(:partisan, :overlay, new_config)

# Step 3: Verify topology is working
case verify_topology_health() do
  :ok ->
    Logger.info("Topology transition completed successfully")
    :ok
  {:error, reason} ->
    Logger.error("Topology verification failed: #{reason}")
    {:error, {:verification_failed, reason}}
end

end

Performance Monitoring and Analysis

defp collect_performance_metrics() do %{ node_count: get_cluster_size(), message_latency: measure_message_latency(), connection_count: count_active_connections(), bandwidth_utilization: measure_bandwidth_utilization(), partition_events: count_recent_partitions(), timestamp: :os.system_time(:millisecond) } end

defp determine_optimal_topology(workload_type, state) do cluster_size = get_cluster_size()

case {workload_type, cluster_size} do
  {:low_latency, size} when size <= 10 ->
    :full_mesh
  
  {:high_throughput, size} when size <= 100 ->
    :hyparview
  
  {:massive_scale, size} when size > 100 ->
    :client_server
  
  {:event_driven, _size} ->
    :pub_sub
  
  {_workload, size} when size <= 5 ->
    :full_mesh
  
  {_workload, size} when size <= 50 ->
    :hyparview
  
  {_workload, _size} ->
    :client_server
end

end

defp should_auto_optimize?(state) do current_metrics = state.performance_metrics current_topology = state.current_topology

# Analyze performance indicators
issues = []

issues = if Map.get(current_metrics, :message_latency, 0) > 100 do
  [:high_latency | issues]
else
  issues
end

issues = if Map.get(current_metrics, :partition_events, 0) > 5 do
  [:frequent_partitions | issues]
else
  issues
end

issues = if Map.get(current_metrics, :bandwidth_utilization, 0) > 0.8 do
  [:high_bandwidth | issues]
else
  issues
end

# Determine if optimization is needed
case {issues, current_topology} do
  {[], _topology} ->
    :no
  
  {[:high_latency], :hyparview} when get_cluster_size() <= 10 ->
    {:yes, :full_mesh}
  
  {[:frequent_partitions], :full_mesh} when get_cluster_size() > 20 ->
    {:yes, :hyparview}
  
  {[:high_bandwidth], topology} when topology != :client_server and get_cluster_size() > 50 ->
    {:yes, :client_server}
  
  _other ->
    :no
end

end

defp analyze_topology_performance(state) do current_metrics = state.performance_metrics history = state.topology_history

%{
  current_performance: current_metrics,
  topology_efficiency: calculate_topology_efficiency(current_metrics, state.current_topology),
  recommendations: generate_topology_recommendations(current_metrics, state.current_topology),
  historical_performance: analyze_historical_performance(history),
  cluster_health: assess_cluster_health()
}

end

Utility Functions

defp initialize_overlay_config() do get_overlay_config_for_topology(:full_mesh) end

defp can_switch_topology?(state) do last_switch_time = get_last_switch_time(state) current_time = :os.system_time(:millisecond)

case last_switch_time do
  nil -> true
  last_time -> (current_time - last_time) > state.switch_cooldown
end

end

defp get_last_switch_time(state) do case state.topology_history do [] -> nil [latest | _] -> latest.timestamp end end

defp schedule_performance_monitoring() do Process.send_after(self(), :monitor_performance, 30_000) # Every 30 seconds end

defp get_cluster_size() do length([Node.self() | Node.list()]) end

defp announce_topology_change(new_topology) do message = {:topology_change_announcement, new_topology, Node.self()} # Would send via Partisan when available Logger.info(“Announcing topology change to #{new_topology}”) end

defp verify_topology_health() do # Simple health check - in real implementation would verify Partisan connectivity :timer.sleep(1000) :ok end

Performance measurement stubs (would be implemented with actual metrics)

defp measure_message_latency(), do: :rand.uniform(50) + 10 defp count_active_connections(), do: get_cluster_size() - 1 defp measure_bandwidth_utilization(), do: :rand.uniform(100) / 100 defp count_recent_partitions(), do: 0 defp get_current_performance_metrics(), do: %{} defp calculate_topology_efficiency(_metrics, _topology), do: 0.85 defp generate_topology_recommendations(_metrics, _topology), do: [] defp analyze_historical_performance(_history), do: %{} defp assess_cluster_health(), do: :healthy end

Foundation.Distributed.Channels - Multi-Channel Communication

lib/foundation/distributed/channels.ex

defmodule Foundation.Distributed.Channels do @moduledoc """ Multi-channel communication system that eliminates head-of-line blocking.

Provides separate channels for different types of traffic:

• :coordination - High-priority cluster coordination messages
• :data - Application data transfer
• :gossip - Background gossip and maintenance
• :events - Event streaming and notifications """

use GenServer require Logger

defstruct [ :channel_registry, :routing_table, :performance_metrics, :channel_configs, :load_balancer ]

Public API

@doc """ Sends a message on a specific channel. """ def send_message(channel, destination, message, opts \ []) do GenServer.call(MODULE, {:send_message, channel, destination, message, opts}) end

@doc """ Broadcasts a message to all nodes on a specific channel. """ def broadcast(channel, message, opts \ []) do GenServer.call(MODULE, {:broadcast, channel, message, opts}) end

@doc """ Sets up message routing rules for intelligent channel selection. """ def configure_routing(rules) do GenServer.call(MODULE, {:configure_routing, rules}) end

@doc """ Monitors channel performance and utilization. """ def get_channel_metrics() do GenServer.call(MODULE, :get_channel_metrics) end

GenServer Implementation

def start_link(opts \ []) do GenServer.start_link(MODULE, opts, name: MODULE) end

@impl true def init(opts) do state = %MODULE{ channel_registry: initialize_channel_registry(), routing_table: initialize_routing_table(), performance_metrics: %{}, channel_configs: initialize_channel_configs(), load_balancer: initialize_load_balancer() }

# Set up Partisan channels (when available)
setup_channels(state.channel_configs)

# Start performance monitoring
schedule_metrics_collection()

{:ok, state}

end

@impl true def handle_call({:send_message, channel, destination, message, opts}, _from, state) do case route_message(channel, destination, message, opts, state) do {:ok, routing_info} -> result = execute_message_send(routing_info) update_metrics(channel, routing_info, result, state) {:reply, result, state} {:error, reason} -> {:reply, {:error, reason}, state} end end

@impl true def handle_call({:broadcast, channel, message, opts}, _from, state) do case route_broadcast(channel, message, opts, state) do {:ok, routing_info} -> result = execute_broadcast(routing_info) update_metrics(channel, routing_info, result, state) {:reply, result, state} {:error, reason} -> {:reply, {:error, reason}, state} end end

@impl true def handle_call({:configure_routing, rules}, _from, state) do new_routing_table = apply_routing_rules(state.routing_table, rules) new_state = %{state | routing_table: new_routing_table} {:reply, :ok, new_state} end

@impl true def handle_call(:get_channel_metrics, _from, state) do metrics = compile_channel_metrics(state) {:reply, metrics, state} end

@impl true def handle_info(:collect_metrics, state) do new_metrics = collect_channel_performance_metrics() new_state = %{state | performance_metrics: new_metrics}

# Check for channel optimization opportunities
optimize_channels_if_needed(new_state)

schedule_metrics_collection()
{:noreply, new_state}

end

Channel Setup and Configuration

defp initialize_channel_configs() do %{ coordination: %{ priority: :high, reliability: :guaranteed, max_connections: 3, buffer_size: 1000, compression: false },

  data: %{
    priority: :medium,
    reliability: :best_effort,
    max_connections: 5,
    buffer_size: 10000,
    compression: true
  },
  
  gossip: %{
    priority: :low,
    reliability: :best_effort,
    max_connections: 1,
    buffer_size: 5000,
    compression: true
  },
  
  events: %{
    priority: :medium,
    reliability: :at_least_once,
    max_connections: 2,
    buffer_size: 5000,
    compression: false
  }
}

end

defp setup_channels(channel_configs) do Enum.each(channel_configs, fn {channel_name, config} -> Logger.info(“Setting up channel #{channel_name} with config: #{inspect(config)}”) # Would configure Partisan channels when available end) end

Message Routing Implementation

defp route_message(channel, destination, message, opts, state) do # Determine optimal routing strategy routing_strategy = determine_routing_strategy(channel, destination, message, opts, state)

case routing_strategy do
  {:direct, target_node} ->
    {:ok, %{
      strategy: :direct,
      channel: channel,
      destination: target_node,
      message: message,
      opts: opts
    }}
  
  {:load_balanced, candidate_nodes} ->
    optimal_node = select_optimal_node(candidate_nodes, state.load_balancer)
    {:ok, %{
      strategy: :load_balanced,
      channel: channel,
      destination: optimal_node,
      message: message,
      opts: opts
    }}
  
  {:error, reason} ->
    {:error, reason}
end

end

defp determine_routing_strategy(channel, destination, message, opts, state) do case destination do node when is_atom(node) -> # Direct node targeting if Node.alive?(node) do {:direct, node} else {:error, {:node_not_available, node}} end

  :all ->
    # Broadcast to all nodes
    {:broadcast_all, Node.list([:visible])}
  
  {:service, service_name} ->
    # Route to service instances
    case find_service_instances(service_name) do
      [] -> {:error, {:no_service_instances, service_name}}
      instances -> {:load_balanced, instances}
    end
  
  {:capability, capability} ->
    # Route to nodes with specific capability
    case find_nodes_with_capability(capability) do
      [] -> {:error, {:no_capable_nodes, capability}}
      nodes -> {:load_balanced, nodes}
    end
end

end

defp execute_message_send(routing_info) do case routing_info.strategy do :direct -> # Would use Partisan when available, fallback to standard send send({:foundation_distributed, routing_info.destination}, routing_info.message) :ok

  :load_balanced ->
    send({:foundation_distributed, routing_info.destination}, routing_info.message)
    :ok
end

end

defp route_broadcast(channel, message, opts, state) do broadcast_strategy = determine_broadcast_strategy(channel, message, opts)

case broadcast_strategy do
  :simple_broadcast ->
    {:ok, %{
      strategy: :simple_broadcast,
      channel: channel,
      message: message,
      targets: Node.list([:visible])
    }}
  
  :staged_broadcast ->
    {:ok, %{
      strategy: :staged_broadcast,
      channel: channel,
      message: message,
      stages: calculate_broadcast_stages(Node.list([:visible]))
    }}
  
  :gossip_broadcast ->
    {:ok, %{
      strategy: :gossip_broadcast,
      channel: channel,
      message: message,
      fanout: Keyword.get(opts, :fanout, 3)
    }}
end

end

defp determine_broadcast_strategy(channel, message, opts) do message_size = estimate_message_size(message) urgency = Keyword.get(opts, :urgency, :normal)

cond do
  urgency == :high and message_size < 1024 ->
    :simple_broadcast
  
  message_size > 10_240 ->
    :staged_broadcast
  
  channel == :gossip ->
    :gossip_broadcast
  
  true ->
    :simple_broadcast
end

end

defp execute_broadcast(routing_info) do case routing_info.strategy do :simple_broadcast -> Enum.each(routing_info.targets, fn node -> send({:foundation_distributed, node}, routing_info.message) end) :ok

  :staged_broadcast ->
    execute_staged_broadcast(routing_info)
  
  :gossip_broadcast ->
    execute_gossip_broadcast(routing_info)
end

end

Advanced Broadcasting Strategies

defp execute_staged_broadcast(routing_info) do stages = routing_info.stages

# Send to first stage immediately
first_stage = hd(stages)
Enum.each(first_stage, fn node ->
  send({:foundation_distributed, node}, routing_info.message)
end)

# Schedule remaining stages
remaining_stages = tl(stages)
Enum.with_index(remaining_stages, 1)
|> Enum.each(fn {stage, index} ->
  delay = index * 100  # 100ms between stages
  
  spawn(fn ->
    :timer.sleep(delay)
    Enum.each(stage, fn node ->
      send({:foundation_distributed, node}, routing_info.message)
    end)
  end)
end)

:ok

end

defp execute_gossip_broadcast(routing_info) do fanout = routing_info.fanout available_nodes = Node.list([:visible])

# Select random subset for gossip
gossip_targets = Enum.take_random(available_nodes, fanout)

gossip_message = %{
  type: :gossip_broadcast,
  original_message: routing_info.message,
  ttl: 3,  # Time to live
  source: Node.self()
}

Enum.each(gossip_targets, fn node ->
  send({:foundation_distributed, node}, gossip_message)
end)

:ok

end

Performance Monitoring and Optimization

defp collect_channel_performance_metrics() do channels = [:coordination, :data, :gossip, :events]

Enum.into(channels, %{}, fn channel ->
  metrics = %{
    message_count: get_channel_message_count(channel),
    bytes_transferred: get_channel_bytes_transferred(channel),
    average_latency: get_channel_average_latency(channel),
    error_rate: get_channel_error_rate(channel),
    utilization: get_channel_utilization(channel)
  }
  
  {channel, metrics}
end)

end

defp optimize_channels_if_needed(state) do # Analyze performance metrics and optimize channels Enum.each(state.performance_metrics, fn {channel, metrics} -> cond do metrics[:utilization] > 0.9 -> Logger.info(“Channel #{channel} highly utilized, consider scaling”) scale_channel_if_possible(channel)

    metrics[:error_rate] > 0.1 ->
      Logger.warning("Channel #{channel} has high error rate: #{metrics[:error_rate]}")
      diagnose_channel_issues(channel)
    
    true ->
      :ok
  end
end)

end

Utility Functions

defp initialize_channel_registry() do :ets.new(:channel_registry, [:set, :protected]) end

defp initialize_routing_table() do %{ default_routes: %{}, service_routes: %{}, capability_routes: %{} } end

defp initialize_load_balancer() do %{ strategy: :round_robin, node_weights: %{}, health_status: %{} } end

defp schedule_metrics_collection() do Process.send_after(self(), :collect_metrics, 10_000) # Every 10 seconds end

defp find_service_instances(service_name) do # Would integrate with service registry case Foundation.ServiceRegistry.lookup(:default, service_name) do {:ok, _pid} -> [Node.self()] _ -> [] end end

defp find_nodes_with_capability(capability) do # Would integrate with capability registry [Node.self()] end

defp select_optimal_node(candidate_nodes, load_balancer) do case load_balancer.strategy do :round_robin -> # Simple round robin selection Enum.random(candidate_nodes)

  :weighted ->
    # Weighted selection based on node capacity
    select_weighted_node(candidate_nodes, load_balancer.node_weights)
  
  :health_based ->
    # Select healthiest node
    select_healthiest_node(candidate_nodes, load_balancer.health_status)
end

end

defp calculate_broadcast_stages(nodes) do # Split nodes into stages for staged broadcasting stage_size = max(1, div(length(nodes), 3)) Enum.chunk_every(nodes, stage_size) end

defp estimate_message_size(message) do # Rough estimation without full serialization try do :erlang.external_size(message) rescue _ -> 1000 # Default estimate end end

Performance measurement stubs (would be implemented with actual metrics)

defp get_channel_message_count(_channel), do: :rand.uniform(1000) defp get_channel_bytes_transferred(_channel), do: :rand.uniform(1_000_000) defp get_channel_average_latency(_channel), do: :rand.uniform(50) + 5 defp get_channel_error_rate(_channel), do: :rand.uniform(10) / 100 defp get_channel_utilization(_channel), do: :rand.uniform(100) / 100

defp scale_channel_if_possible(_channel), do: :ok defp diagnose_channel_issues(_channel), do: :ok defp select_weighted_node(nodes, _weights), do: Enum.random(nodes) defp select_healthiest_node(nodes, _health), do: Enum.random(nodes) defp apply_routing_rules(routing_table, _rules), do: routing_table defp compile_channel_metrics(state), do: state.performance_metrics defp update_metrics(_channel, _routing_info, _result, _state), do: :ok end

Foundation.Distributed.Discovery - Intelligent Service Discovery

lib/foundation/distributed/discovery.ex

defmodule Foundation.Distributed.Discovery do @moduledoc """ Intelligent service discovery that works across cluster topologies.

Provides capability-based service matching, health-aware selection, and cross-cluster service federation. """

use GenServer require Logger

defstruct [ :discovery_strategies, :service_cache, :health_monitors, :capability_index ]

Public API

@doc """ Discovers services based on criteria.

Examples

  # Find all database services
  Foundation.Distributed.Discovery.discover_services(service_type: :database)
  
  # Find services with specific capabilities
  Foundation.Distributed.Discovery.discover_services(
    capabilities: [:read_replica, :high_availability]
  )
  
  # Find healthy services on specific nodes
  Foundation.Distributed.Discovery.discover_services(
    health_status: :healthy,
    nodes: [:node1, :node2]
  )

""" def discover_services(criteria \ []) do GenServer.call(MODULE, {:discover_services, criteria}) end

@doc """ Registers a service with capabilities. """ def register_service(service_name, pid, capabilities \ []) do GenServer.call(MODULE, {:register_service, service_name, pid, capabilities}) end

@doc """ Gets the health status of discovered services. """ def get_service_health(service_name) do GenServer.call(MODULE, {:get_service_health, service_name}) end

GenServer Implementation

def start_link(opts \ []) do GenServer.start_link(MODULE, opts, name: MODULE) end

@impl true def init(opts) do state = %MODULE{ discovery_strategies: [:local, :cluster, :external], service_cache: %{}, health_monitors: %{}, capability_index: %{} }

# Start health monitoring
start_health_monitoring()

{:ok, state}

end

@impl true def handle_call({:discover_services, criteria}, _from, state) do case discover_with_criteria(criteria, state) do {:ok, services} -> {:reply, {:ok, services}, state} {:error, reason} -> {:reply, {:error, reason}, state} end end

@impl true def handle_call({:register_service, service_name, pid, capabilities}, _from, state) do new_state = register_service_locally(service_name, pid, capabilities, state) {:reply, :ok, new_state} end

@impl true def handle_call({:get_service_health, service_name}, _from, state) do health = get_health_status(service_name, state) {:reply, health, state} end

Service Discovery Implementation

defp discover_with_criteria(criteria, state) do # Start with local services local_matches = find_local_matches(criteria, state)

# Expand to cluster if needed
cluster_matches = if :cluster in state.discovery_strategies do
  find_cluster_matches(criteria)
else
  []
end

# Combine and filter results
all_matches = local_matches ++ cluster_matches
filtered_matches = apply_discovery_filters(all_matches, criteria)

{:ok, filtered_matches}

end

defp find_local_matches(criteria, state) do Enum.filter(state.service_cache, fn {_name, service} -> matches_discovery_criteria?(service, criteria) end) |> Enum.map(fn {_name, service} -> service end) end

defp find_cluster_matches(criteria) do # Would query other nodes in cluster # For now, return empty list [] end

defp matches_discovery_criteria?(service, criteria) do Enum.all?(criteria, fn {key, value} -> case key do :service_type -> Map.get(service, :service_type) == value

    :capabilities ->
      required_caps = List.wrap(value)
      service_caps = Map.get(service, :capabilities, [])
      Enum.all?(required_caps, &(&1 in service_caps))
    
    :health_status ->
      Map.get(service, :health_status) == value
    
    :nodes ->
      service_node = Map.get(service, :node)
      service_node in List.wrap(value)
    
    _ ->
      true
  end
end)

end

defp register_service_locally(service_name, pid, capabilities, state) do service = %{ name: service_name, pid: pid, node: Node.self(), capabilities: capabilities, health_status: :healthy, registered_at: :os.system_time(:millisecond) }

new_cache = Map.put(state.service_cache, service_name, service)
new_capability_index = update_capability_index(state.capability_index, service_name, capabilities)

%{state | 
  service_cache: new_cache,
  capability_index: new_capability_index
}

end

defp update_capability_index(index, service_name, capabilities) do Enum.reduce(capabilities, index, fn capability, acc -> services = Map.get(acc, capability, []) Map.put(acc, capability, [service_name | services]) end) end

defp apply_discovery_filters(services, criteria) do # Apply additional filters like proximity, load, etc. services end

defp get_health_status(service_name, state) do case Map.get(state.service_cache, service_name) do nil -> {:error, :service_not_found} service -> {:ok, Map.get(service, :health_status, :unknown)} end end

defp start_health_monitoring() do spawn_link(fn -> health_monitoring_loop() end) end

defp health_monitoring_loop() do # Would monitor service health :timer.sleep(30_000) health_monitoring_loop() end end