policy_failure_matrix/
policy_failure_matrix.rs

1//! Demonstrates policy decisions across typed task exits and fuse tracking.
2
3// Import restart backoff policy values.
4use rust_supervisor::policy::backoff::BackoffPolicy;
5// Import typed restart policy decision values.
6use rust_supervisor::policy::decision::{PolicyEngine, PolicyFailureKind, RestartPolicy, TaskExit};
7// Import meltdown fuse policy values.
8use rust_supervisor::policy::meltdown::{MeltdownPolicy, MeltdownTracker};
9// Import duration and instant values for deterministic examples.
10use std::time::{Duration, Instant};
11
12// Run the policy failure matrix example.
13/// Runs the policy failure matrix example.
14fn main() {
15    // Build the reusable backoff policy.
16    let backoff = BackoffPolicy::new(
17        // Set the initial delay.
18        Duration::from_millis(100),
19        // Set the maximum delay.
20        Duration::from_secs(5),
21        // Set jitter percent.
22        10,
23        // Set the reset window.
24        Duration::from_secs(60),
25        // Finish the reusable backoff policy.
26    )
27    // Enable deterministic jitter for repeatable output.
28    .with_deterministic_jitter(42);
29    // Create the stateless policy engine.
30    let engine = PolicyEngine::new();
31
32    // Iterate over policy and exit combinations.
33    for (policy, exit) in [
34        // Include a permanent policy after success.
35        (RestartPolicy::Permanent, TaskExit::Succeeded),
36        // Include a transient external dependency failure.
37        (
38            // Select transient restart behavior.
39            RestartPolicy::Transient,
40            // Build an external dependency failure exit.
41            TaskExit::Failed {
42                // Set the failure category.
43                kind: PolicyFailureKind::ExternalDependency,
44                // Finish the failure exit.
45            },
46            // Finish the policy and exit pair.
47        ),
48        // Include a transient fatal bug failure.
49        (
50            // Select transient restart behavior.
51            RestartPolicy::Transient,
52            // Build a fatal bug failure exit.
53            TaskExit::Failed {
54                // Set the failure category.
55                kind: PolicyFailureKind::FatalBug,
56                // Finish the failure exit.
57            },
58            // Finish the policy and exit pair.
59        ),
60        // Include a temporary panic failure.
61        (
62            // Select temporary restart behavior.
63            RestartPolicy::Temporary,
64            // Build a panic failure exit.
65            TaskExit::Failed {
66                // Set the failure category.
67                kind: PolicyFailureKind::Panic,
68                // Finish the failure exit.
69            },
70            // Finish the policy and exit pair.
71        ),
72        // Finish the decision matrix.
73    ] {
74        // Calculate the restart decision.
75        let decision = engine.decide(policy, exit, 3, &backoff);
76        // Print the policy decision row.
77        println!("policy={policy:?} exit={exit:?} decision={decision:?}");
78        // Finish the matrix loop.
79    }
80
81    // Build the meltdown fuse policy.
82    let policy = MeltdownPolicy::new(
83        // Set the child restart limit.
84        2,
85        // Set the child restart window.
86        Duration::from_secs(60),
87        // Set the supervisor failure limit.
88        5,
89        // Set the supervisor failure window.
90        Duration::from_secs(60),
91        // Set the stable reset window.
92        Duration::from_secs(300),
93        // Finish the meltdown policy construction.
94    );
95    // Create the mutable meltdown tracker.
96    let mut tracker = MeltdownTracker::new(policy);
97    // Capture the current monotonic instant.
98    let now = Instant::now();
99
100    // Iterate over restart offsets.
101    for offset_ms in [0, 10, 20] {
102        // Record a child restart at the offset instant.
103        let outcome = tracker.record_child_restart(now + Duration::from_millis(offset_ms));
104        // Print the fuse state after the restart.
105        println!(
106            // Provide the output template.
107            "restart_at_ms={offset_ms} child_failures={} outcome={outcome:?}",
108            // Include the current child failure count.
109            tracker.child_failure_count(),
110            // Finish printing the fuse state.
111        );
112        // Finish the fuse loop.
113    }
114    // End the policy failure matrix example.
115}
policy_failure_matrix/policy_failure_matrix.rs

policy_failure_matrix/
policy_failure_matrix.rs
