//! Module: metrics report rendering.
//! Responsibility: render canonical journal debt and one execution-cost window.
//! Does not own: endpoint calls, Candid decoding, or endpoint publication.
use icydb::metrics::{EntityMetrics, MetricsReport};
use crate::table::{ColumnAlign, append_indented_table};
type MetricsEntityRow = [String; 5];
const HEADERS: [&str; 5] = ["entity", "hits", "instructions", "average", "max"];
const ALIGNMENTS: [ColumnAlign; 5] = [
ColumnAlign::Left,
ColumnAlign::Right,
ColumnAlign::Right,
ColumnAlign::Right,
ColumnAlign::Right,
];
pub(super) fn render_metrics_report(report: &MetricsReport) -> String {
let debt = report.journal_debt();
let convergence = report.convergence();
let appended = convergence.appended();
let retired = convergence.retired();
let mut output = format!(
"IcyDB metrics\n window: {}..{} ({} ms)\n heap-local window ID: {}\n entities: {} of {} (bounded path prefix, sorted by cost)\n\njournal\n canonical debt: {} batches, {} records, {} encoded batch bytes\n window appended: {} batches, {} records, {} encoded batch bytes\n window retired: {} batches, {} records, {} encoded batch bytes\n movement overflowed: {}\n fold: {} samples, {} total instructions, {} max instructions\n startup recovery: {} samples, {} total instructions, {} max instructions\n instruction spans may nest; totals are not additive\n\nentities\n",
report.window_start_ms(),
report.window_end_ms(),
report
.window_end_ms()
.saturating_sub(report.window_start_ms()),
report
.window_id()
.map_or_else(|| "unavailable".to_string(), |id| id.to_string()),
report.entities().len(),
report.total_entities(),
debt.batch_count(),
debt.record_count(),
debt.encoded_batch_bytes(),
appended.batch_count(),
appended.record_count(),
appended.encoded_batch_bytes(),
retired.batch_count(),
retired.record_count(),
retired.encoded_batch_bytes(),
convergence.overflowed(),
convergence.journal_fold().samples(),
convergence.journal_fold().instructions_total(),
convergence.journal_fold().instructions_max(),
report.schema_lifecycle().startup_recovery().samples(),
report
.schema_lifecycle()
.startup_recovery()
.instructions_total(),
report
.schema_lifecycle()
.startup_recovery()
.instructions_max(),
);
if report.entities().is_empty() {
output.push_str(" None\n");
return output;
}
let rows = report.entities().iter().map(entity_row).collect::<Vec<_>>();
append_indented_table(&mut output, " ", &HEADERS, &rows, &ALIGNMENTS);
output
}
fn entity_row(entity: &EntityMetrics) -> MetricsEntityRow {
// Counts and totals saturate independently; unavailable means are not zero.
let average = match ic_metrics::checked_mean(entity.hits(), entity.instructions_total()) {
Ok(Some(value)) => value.to_string(),
Ok(None) | Err(_) => "unavailable".to_string(),
};
[
entity.path().to_string(),
entity.hits().to_string(),
entity.instructions_total().to_string(),
average,
entity.instructions_max().to_string(),
]
}
#[cfg(test)]
mod tests {
use super::entity_row;
use icydb::metrics::EntityMetrics;
fn decoded_entity(hits: u64, total: u64) -> EntityMetrics {
serde_json::from_value(serde_json::json!({
"path": "app.Entity",
"hits": hits,
"instructions_total": total,
"instructions_max": total,
}))
.expect("decode report entity")
}
#[test]
fn metrics_entity_row_keeps_fields_and_rounds_average_down() {
assert_eq!(
entity_row(&decoded_entity(3, 10)),
["app.Entity", "3", "10", "3", "10"].map(str::to_string),
);
}
#[test]
fn metrics_average_distinguishes_empty_from_measured_zero() {
assert_eq!(entity_row(&decoded_entity(0, 0))[3], "unavailable");
assert_eq!(entity_row(&decoded_entity(3, 0))[3], "0");
}
#[test]
fn metrics_average_rejects_inconsistent_or_saturated_report_fields() {
for (hits, total) in [(0, 1), (1, u64::MAX), (u64::MAX, 0), (u64::MAX, u64::MAX)] {
assert_eq!(entity_row(&decoded_entity(hits, total))[3], "unavailable");
}
assert_eq!(
entity_row(&decoded_entity(1, u64::MAX - 1))[3],
(u64::MAX - 1).to_string()
);
}
}