Feature/event injection input (#19)

* Structure defined for the pydantic model representing Event to be injected

* Pydantic validation in the payload for events part 1

* Definition of the input for the events injection part 2

* minor fixes ruff and mypy compliant

* full tests and docs added for input event injection

* fixed minor bugs

Author: GioeleB00

docs/api/event-injection.md

@@ -0,0 +1,246 @@
+# EventInjection — Public API Documentation
+
+## Overview
+
+`EventInjection` declares a **time-bounded event** that affects a component in the simulation. Each event targets either a **server** or a **network edge**, and is delimited by a `start` marker and an `end` marker.
+
+Supported families (per code):
+
+* **Server availability**: `SERVER_DOWN` → `SERVER_UP`
+* **Network latency spike (deterministic offset in seconds)**: `NETWORK_SPIKE_START` → `NETWORK_SPIKE_END`
+  For network spikes, the `Start` marker carries the amplitude in seconds via `spike_s`.
+
+Strictness:
+
+* Models use `ConfigDict(extra="forbid", frozen=True)`
+  → unknown fields are rejected; instances are immutable at runtime.
+
+---
+
+## Data Model
+
+### `Start`
+
+* `kind: Literal[SERVER_DOWN, NETWORK_SPIKE_START]`
+  Event family selector.
+* `t_start: NonNegativeFloat`
+  Start time in **seconds** from simulation start; **≥ 0.0**.
+* `spike_s: PositiveFloat | None`
+  **Required** and **> 0** **only** when `kind == NETWORK_SPIKE_START`.
+  **Forbidden** (must be omitted/`None`) for any other kind.
+
+### `End`
+
+* `kind: Literal[SERVER_UP, NETWORK_SPIKE_END]`
+  Must match the start family (see invariants).
+* `t_end: PositiveFloat`
+  End time in **seconds**; **> 0.0**.
+
+### `EventInjection`
+
+* `event_id: str`
+  Unique identifier within the simulation payload.
+* `target_id: str`
+  Identifier of the affected component (server or edge) as defined in the topology.
+* `start: Start`
+  Start marker.
+* `end: End`
+  End marker.
+
+---
+
+## Validation & Invariants (as implemented)
+
+### Within `EventInjection`
+
+1. **Family coherence**
+
+   * `SERVER_DOWN` → `SERVER_UP`
+   * `NETWORK_SPIKE_START` → `NETWORK_SPIKE_END`
+     Any other pairing raises:
+
+   ```
+   The event {event_id} must have as value of kind in end {expected}
+   ```
+2. **Temporal ordering**
+
+   * `t_start < t_end` (with `t_start ≥ 0.0`, `t_end > 0.0`)
+     Error:
+
+   ```
+   The starting time for the event {event_id} must be smaller than the ending time
+   ```
+3. **Network spike parameter**
+
+   * If `start.kind == NETWORK_SPIKE_START` ⇒ `start.spike_s` **must** be provided and be a positive float (seconds).
+     Error:
+
+     ```
+     The field spike_s for the event {event_id} must be defined as a positive float (seconds)
+     ```
+   * Otherwise (`SERVER_DOWN`) ⇒ `start.spike_s` **must be omitted** / `None`.
+     Error:
+
+     ```
+     Event {event_id}: spike_s must be omitted for non-network events
+     ```
+
+### Enforced at `SimulationPayload` level
+
+4. **Unique event IDs**
+   Error:
+
+   ```
+   The id's representing different events must be unique
+   ```
+5. **Target existence & compatibility**
+
+   * For server events (`SERVER_DOWN`), `target_id` must refer to a **server**.
+   * For network spikes (`NETWORK_SPIKE_START`), `target_id` must refer to an **edge**.
+     Errors:
+
+   ```
+   The target id {target_id} related to the event {event_id} does not exist
+   ```
+
+   ```
+   The event {event_id} regarding a server does not have a compatible target id
+   ```
+
+   ```
+   The event {event_id} regarding an edge does not have a compatible target id
+   ```
+6. **Times within simulation horizon** (with `T = sim_settings.total_simulation_time`)
+
+   * `t_start >= 0.0` and `t_start <= T`
+   * `t_end <= T`
+     Errors:
+
+   ```
+   Event '{event_id}': start time t_start={t:.6f} must be >= 0.0
+   Event '{event_id}': start time t_start={t:.6f} exceeds simulation horizon T={T:.6f}
+   Event '{event_id}': end time t_end={t:.6f} exceeds simulation horizon T={T:.6f}
+   ```
+7. **Global liveness rule (servers)**
+   The payload is rejected if **all servers are down at the same moment**.
+   Implementation detail: the timeline is ordered so that, at identical timestamps, **`END` is processed before `START`** to avoid transient all-down states.
+   Error:
+
+   ```
+   At time {time:.6f} all servers are down; keep at least one up
+   ```
+
+---
+
+## Runtime Semantics (summary)
+
+* **Server events**: the targeted server is unavailable between the start and end markers; the system enforces that at least one server remains up at all times.
+* **Network spike events**: the targeted edge’s latency sampler is deterministically **shifted by `spike_s` seconds** during the event window (additive congestion model). The underlying distribution is not reshaped—samples are translated by a constant offset.
+
+*(This reflects the agreed model: deterministic additive offset on edges.)*
+
+---
+
+## Units & Precision
+
+* All times and offsets are in **seconds** (floating-point).
+* Provide values with the precision your simulator supports; microsecond-level precision is acceptable if needed.
+
+---
+
+## Authoring Guidelines
+
+* **Do not include `spike_s`** for non-network events.
+* Use **stable, meaningful `event_id`** values for auditability.
+* Keep events within the **simulation horizon**.
+* When multiple markers share the same timestamp, rely on the engine’s **END-before-START** ordering for determinism.
+
+---
+
+## Examples
+
+### 1) Valid — Server maintenance window
+
+```yaml
+event_id: ev-maint-001
+target_id: srv-1
+start: { kind: SERVER_DOWN, t_start: 120.0 }
+end:   { kind: SERVER_UP,   t_end:   240.0 }
+```
+
+### 2) Valid — Network spike on an edge (+8 ms)
+
+```yaml
+event_id: ev-spike-008ms
+target_id: edge-12
+start: { kind: NETWORK_SPIKE_START, t_start: 10.0, spike_s: 0.008 }
+end:   { kind: NETWORK_SPIKE_END,   t_end:   25.0 }
+```
+
+### 3) Invalid — Missing `spike_s` for a network spike
+
+```yaml
+event_id: ev-missing-spike
+target_id: edge-5
+start: { kind: NETWORK_SPIKE_START, t_start: 5.0 }
+end:   { kind: NETWORK_SPIKE_END,   t_end:  15.0 }
+```
+
+Error:
+
+```
+The field spike_s for the event ev-missing-spike must be defined as a positive float (seconds)
+```
+
+### 4) Invalid — `spike_s` present for a server event
+
+```yaml
+event_id: ev-bad-spike
+target_id: srv-2
+start: { kind: SERVER_DOWN, t_start: 50.0, spike_s: 0.005 }
+end:   { kind: SERVER_UP,   t_end:   60.0 }
+```
+
+Error:
+
+```
+Event ev-bad-spike: spike_s must be omitted for non-network events
+```
+
+### 5) Invalid — Mismatched families
+
+```yaml
+event_id: ev-bad-kinds
+target_id: edge-1
+start: { kind: NETWORK_SPIKE_START, t_start: 5.0, spike_s: 0.010 }
+end:   { kind: SERVER_UP,           t_end:  15.0 }
+```
+
+Error:
+
+```
+The event ev-bad-kinds must have as value of kind in end NETWORK_SPIKE_END
+```
+
+### 6) Invalid — Start not before End
+
+```yaml
+event_id: ev-bad-time
+target_id: srv-2
+start: { kind: SERVER_DOWN, t_start: 300.0 }
+end:   { kind: SERVER_UP,   t_end:   300.0 }
+```
+
+Error:
+
+```
+The starting time for the event ev-bad-time must be smaller than the ending time
+```
+
+---
+
+## Notes for Consumers
+
+* The schema is **strict**: misspelled fields (e.g., `t_strat`) are rejected.
+* The engine may combine multiple active network spikes on the same edge by **summing** their `spike_s` values while they overlap (handled by runtime bookkeeping).
+* This document describes exactly what is present in the provided code and validators; no additional fields or OpenAPI metadata are assumed.

src/asyncflow/components/__init__.py

@@ -1,6 +1,7 @@
 """Public components: re-exports Pydantic schemas (topology)."""
 from __future__ import annotations
 
+from asyncflow.schemas.event.injection import EventInjection
 from asyncflow.schemas.topology.edges import Edge
 from asyncflow.schemas.topology.endpoint import Endpoint
 from asyncflow.schemas.topology.nodes import (
@@ -10,6 +11,14 @@
     ServerResources,
 )
 
-__all__ = ["Client", "Edge", "Endpoint", "LoadBalancer", "Server", "ServerResources"]
+__all__ = [
+    "Client",
+    "Edge",
+    "Endpoint",
+    "EventInjection",
+    "LoadBalancer",
+    "Server",
+    "ServerResources",
+    ]
 
 

src/asyncflow/config/constants.py

@@ -175,6 +175,19 @@ class SystemEdges(StrEnum):
 
     NETWORK_CONNECTION = "network_connection"
 
+# ======================================================================
+# CONSTANTS FOR THE EVENT TO INJECT IN THE SIMULATION
+# ======================================================================
+
+class EventDescription(StrEnum):
+  """Description for the events you may inject during the simulation"""
+
+  SERVER_UP = "server_up"
+  SERVER_DOWN = "server_down"
+  NETWORK_SPIKE_START = "network_spike_start"
+  NETWORK_SPIKE_END = "network_spike_end"
+
+
 # ======================================================================
 # CONSTANTS FOR SAMPLED METRICS
 # ======================================================================