Move scattered magic constants into src/consts.rs

Centralizes engine tuning values, poll intervals, logfmt column
regex fragments, and app/settings identity strings that were
previously defined ad hoc across engine.rs, ingest.rs, logfmt.rs,
profile.rs, settings.rs, and main.rs.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01A1ZJ3SrayzLzVndhVq9BmS

src/consts.rs

@@ -0,0 +1,54 @@
+use std::time::Duration;
+
+// mpsc channel capacity between ingest/API callers and the engine actor task.
+pub const ENGINE_CHANNEL_CAPACITY: usize = 1024;
+
+// Hard ceiling on how many params `auto_declare_params` will ever create automatically over the
+// life of the engine, so one unusual input can't inflate the declared-param set forever.
+pub const MAX_AUTO_DECLARED_PARAMS: usize = 64;
+
+// Per-line ceiling on how many *new* params a single ingested line may contribute to the
+// auto-derived set, so one unusually wide line can't burn the whole per-run budget at once.
+pub const MAX_NEW_AUTO_PARAMS_PER_LINE: usize = 8;
+
+// How long a sort helper index may sit unused before it's purged and left to rebuild on demand.
+pub const SORT_HELPER_INDEX_PURGE_AFTER: Duration = Duration::from_secs(300);
+
+// Window and capacity for the rolling ingestion-to-engine-processing lag high watermark.
+pub const INGEST_LAG_WATERMARK_WINDOW_MS: i64 = 5000;
+pub const INGEST_LAG_WATERMARK_MAX_ENTRIES: usize = 5;
+
+// Bucket width used to merge multiple sub-series into one combined time series.
+pub const MERGE_WINDOW_MS: i64 = 1_000;
+
+// Default timeline query bucket width when the caller doesn't specify one.
+pub const DEFAULT_TIMELINE_BUCKET_MS: i64 = 1_000;
+
+// Reserved param names usable without declaring anything (ottyl-synthesized columns).
+pub const OTTYL_RESERVED_PARAM_NAMES: [&str; 3] = ["ottyl_seq", "ottyl_ts", "ottyl_fmt"];
+
+// Idle poll cadence while tailing stdin/a file for new log lines.
+pub const STDIN_POLL_INTERVAL: Duration = Duration::from_millis(200);
+
+// Poll cadence for a configured Prometheus/OpenMetrics `--metrics-url`.
+pub const METRICS_POLL_INTERVAL: Duration = Duration::from_secs(15);
+
+// Column-splitting regex fragments for the fixed-width logfmt column parser.
+pub const COLUMN_SEPARATOR_PATTERN: &str = r"(?:\t|[ \t]{2,})";
+pub const COLUMN_VALUE_PATTERN: &str = r"\S+(?: \S+)*";
+
+// Name of the always-present profile every Settings file is seeded with.
+pub const DEFAULT_PROFILE_NAME: &str = "Default";
+
+// Name/label of the metric the Default profile is seeded with.
+pub const SEEDED_METRIC_NAME: &str = "log_category";
+pub const SEEDED_METRIC_LABEL: &str = "category";
+
+// Host the HTTP server binds to; port is user-configurable, host is not.
+pub const DEFAULT_BIND_HOST: &str = "0.0.0.0";
+
+// App identity used to resolve the OS-conventional settings directory, and the settings file name.
+pub const APP_QUALIFIER: &str = "";
+pub const APP_ORGANIZATION: &str = "";
+pub const APP_NAME: &str = "ottyl";
+pub const SETTINGS_FILE_NAME: &str = "settings.json";

src/engine.rs

@@ -1,4 +1,9 @@
 use crate::alerts::{self, AlertRuntimeState};
+use crate::consts::{
+    DEFAULT_TIMELINE_BUCKET_MS, INGEST_LAG_WATERMARK_MAX_ENTRIES, INGEST_LAG_WATERMARK_WINDOW_MS,
+    MAX_AUTO_DECLARED_PARAMS, MAX_NEW_AUTO_PARAMS_PER_LINE, MERGE_WINDOW_MS,
+    OTTYL_RESERVED_PARAM_NAMES, SORT_HELPER_INDEX_PURGE_AFTER,
+};
 use crate::data_value::{DataValue, MetricPrimitiveKind, ParamDeclaration};
 use crate::dto::{
     BucketValueDto, LogEntryDto, LogsParams, MetricDeclarationDto, ParamDeclarationDto,
@@ -605,7 +610,6 @@ fn build_auto_param_pattern(key: &str, group: &str, quoted: bool) -> String {
 /// will never recur meaningfully. Chosen alongside `MAX_NEW_AUTO_PARAMS_PER_LINE` (below) rather than
 /// on its own: a per-line cap alone still lets an unbounded *variety* of lines each contribute a few
 /// new keys forever, so this total ceiling is the actual backstop.
-const MAX_AUTO_DECLARED_PARAMS: usize = 64;
 
 /// Per-line ceiling on how many *new* params a single ingested line may contribute to the auto-derived
 /// set. Without this, one unusually wide line (the fixture's WiFi stat dump has 20+ `key=value` pairs
@@ -613,7 +617,6 @@ const MAX_AUTO_DECLARED_PARAMS: usize = 64;
 /// more representative lines ingested later. Pairs beyond the cap are simply never declared (from this
 /// line or any other, since a later line with fewer pairs would still need to reach them within its own
 /// per-line budget) — acceptable since they're exactly the low-value, one-off counters ticket 050 flags.
-const MAX_NEW_AUTO_PARAMS_PER_LINE: usize = 8;
 
 fn auto_derived_param_count(index: &BTreeMap<IndexKey, DataValue>) -> usize {
     param_declarations_range(index).filter(|declaration| declaration.6).count()
@@ -1662,7 +1665,6 @@ struct SortHelperIndexEntry {
 /// `Settings` (ticket 061 explicitly scopes that out) — a dropped index is always transparently
 /// rebuildable on the next query for that sort key, so this is purely a memory-bound knob, not a
 /// user-visible behavior change.
-const SORT_HELPER_INDEX_PURGE_AFTER: std::time::Duration = std::time::Duration::from_secs(300);
 
 /// Derives a single named param's value from `text`, for helper-index maintenance where deriving
 /// every declared param (`derive_log_params`) per ingested line would be wasted work when only one
@@ -1833,11 +1835,9 @@ fn approx_log_bytes(text: &str) -> u64 {
 
 /// Ticket 073: how long a rolling ingestion-to-engine-processing lag sample stays eligible to be
 /// the reported high watermark.
-const INGEST_LAG_WATERMARK_WINDOW_MS: i64 = 5000;
 /// Ticket 073: at most this many lag samples are held at once — a fresh sample only displaces the
 /// current *lowest*-lag held sample (never appended past this cap), so the collection always
 /// reflects the highest few lags seen recently rather than every sample.
-const INGEST_LAG_WATERMARK_MAX_ENTRIES: usize = 5;
 
 /// Records one `(engine processing time) - (ottyl_ts)` lag sample into the rolling high-watermark
 /// collection the wishlist asked for (ticket 073): up to `INGEST_LAG_WATERMARK_MAX_ENTRIES` samples,
@@ -2128,7 +2128,7 @@ fn handle_query_inner(
                 },
                 None => None,
             };
-            let bucket_ms = params.bucket_ms.unwrap_or(1_000).max(1);
+            let bucket_ms = params.bucket_ms.unwrap_or(DEFAULT_TIMELINE_BUCKET_MS).max(1);
             let mut buckets: BTreeMap<i64, u64> = BTreeMap::new();
             for (sequence, timestamp, text) in logs_range(index).filter(|(_, timestamp, _)| {
                 params.start_ms.is_none_or(|start| timestamp.as_millis() >= start)
@@ -2336,7 +2336,6 @@ fn windowed_rate_series(
 /// the value axis. Occurrence timestamps across different label groups (e.g. different hosts serving
 /// the same path) essentially never land on the same millisecond, so summing/averaging only requires
 /// matching *this* window to combine into "total over time" rather than going sparse (ticket 042).
-const MERGE_WINDOW_MS: i64 = 1_000;
 
 /// Merges several series into one combined time series (ticket 042). A single sub-series is returned
 /// untouched — there's only one contributor, so there's nothing to merge and no reason to lose
@@ -2421,7 +2420,6 @@ fn declared_value_kind(
 /// `compile_ottyl_ts_comparison`/`compile_ottyl_fmt_comparison` for the filter-bar equivalent, and
 /// `webapp/src/components/Docs.tsx` for the user-facing docs. Shared by `evaluate_promql` (dashboard
 /// panels, this file) and `crate::api::list_params` (`GET /api/params` discoverability).
-pub const OTTYL_RESERVED_PARAM_NAMES: [&str; 3] = ["ottyl_seq", "ottyl_ts", "ottyl_fmt"];
 
 /// For `ottyl_seq`/`ottyl_ts` only (not `ottyl_fmt`, which `evaluate_promql` rejects outright before
 /// this is consulted): returns a `(sequence, timestamp_ms) -> value` mapping used to synthesize a

src/ingest.rs

@@ -1,16 +1,12 @@
 use std::collections::BTreeMap;
 use std::path::{Path, PathBuf};
-use std::time::Duration;
 
+use crate::consts::{METRICS_POLL_INTERVAL, STDIN_POLL_INTERVAL as POLL_INTERVAL};
 use crate::engine::{EngineHandle, EngineMessage, IngestedLine, MetricSample};
 use crate::timestamp::Timestamp;
 use tokio::fs::File;
 use tokio::io::{AsyncBufReadExt, BufReader};
 
-const POLL_INTERVAL: Duration = Duration::from_millis(200);
-
-const METRICS_POLL_INTERVAL: Duration = Duration::from_secs(15);
-
 /// Reads stdin line by line, sequences and timestamps each line, and forwards it
 /// to the engine task.
 pub async fn run(engine: EngineHandle) {
@@ -237,6 +233,7 @@ mod openmetrics_tests {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use std::time::Duration;
     use std::io::Write;
     use crate::engine::test_handle;
     use tokio::sync::mpsc;

src/logfmt.rs

@@ -12,6 +12,8 @@ use nom::IResult;
 use regex::Regex;
 use std::sync::LazyLock;
 
+use crate::consts::{COLUMN_SEPARATOR_PATTERN, COLUMN_VALUE_PATTERN};
+
 fn key(input: &str) -> IResult<&str, &str> {
     take_while1(|c: char| c.is_ascii_alphanumeric() || c == '_' || c == '.' || c == '-')(input)
 }
@@ -115,13 +117,6 @@ pub fn is_log_stream_line(line: &str) -> bool {
 /// this is that rule re-expressed as a regex fragment for the trailing message field's
 /// `message_match_regex`, which re-derives its value the same way whenever a caller queries by it
 /// later (declarations don't cache extracted values -- see `crate::engine::extract_param_raw`).
-const COLUMN_SEPARATOR_PATTERN: &str = r"(?:\t|[ \t]{2,})";
-
-/// A column's value: one or more non-whitespace tokens joined by single spaces, with no upper bound
-/// on length. Used for the trailing (unbounded-width) message field and the last named column, where
-/// there's no next column's start position to bound against.
-const COLUMN_VALUE_PATTERN: &str = r"\S+(?: \S+)*";
-
 /// Same idea as `COLUMN_VALUE_PATTERN`, but bounded to a known column `width` (in chars) -- needed for
 /// every column except the last, since two adjacent `log stream` values can legitimately be separated
 /// by only a single space when the first one nearly fills its column's on-screen width (e.g. the

src/main.rs

@@ -1,5 +1,6 @@
 mod alerts;
 mod api;
+mod consts;
 mod data_value;
 mod dto;
 mod engine;
@@ -106,7 +107,7 @@ async fn main() {
 
     let settings = Arc::new(Mutex::new(Settings::load(&settings_path)));
 
-    let engine_tx = engine::spawn(settings.clone(), 1024);
+    let engine_tx = engine::spawn(settings.clone(), consts::ENGINE_CHANNEL_CAPACITY);
     {
         let max_logs = settings.lock().unwrap().max_logs;
         let _ = engine_tx.tx.send(engine::EngineMessage::SetMaxLogs(max_logs)).await;
@@ -154,7 +155,7 @@ async fn main() {
     }
 
     let app = api::router(engine_tx, settings, settings_path.clone());
-    let listener = TcpListener::bind(("0.0.0.0", args.port))
+    let listener = TcpListener::bind((consts::DEFAULT_BIND_HOST, args.port))
         .await
         .expect("failed to bind listener");
     let bound_port = listener

src/profile.rs

@@ -16,14 +16,12 @@ use std::time::{SystemTime, UNIX_EPOCH};
 
 use serde::{Deserialize, Serialize};
 
+use crate::consts::{DEFAULT_PROFILE_NAME, SEEDED_METRIC_LABEL, SEEDED_METRIC_NAME};
 use crate::data_value::MetricPrimitiveKind;
 use crate::engine::{DeclareMetricRequest, DeclareParamRequest, EngineHandle, EngineMessage};
 use crate::settings::Settings;
 use tokio::sync::oneshot;
 
-/// Name of the profile that always exists and can't be deleted (see `Settings::ensure_default_profile`).
-pub const DEFAULT_PROFILE_NAME: &str = "Default";
-
 /// Mirrors `data_value::MetricPrimitiveKind` with `Serialize`/`Deserialize` so profiles can round-trip through JSON, since the engine-internal type only derives `Serialize`.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "lowercase")]
@@ -333,10 +331,6 @@ impl Dashboard {
     }
 }
 
-/// Name of the metric seeded into a brand-new `Default` profile, used to drive its starter dashboard's two panels.
-const SEEDED_METRIC_NAME: &str = "log_category";
-const SEEDED_METRIC_LABEL: &str = "category";
-
 /// A counter that splits every line into `category="error"`/`"other"` via `matched_labels`/`unmatched_labels` rather than a captured param, so case variants like "ERROR" collapse into one series; the `regex` crate lacks the lookaround needed to express "didn't match" any other way.
 fn seeded_error_split_metric() -> MetricDeclarationRecord {
     MetricDeclarationRecord {

src/settings.rs

@@ -182,7 +182,12 @@ pub struct Settings {
 
 /// Computes the default settings file path (`<config_dir>/settings.json`) from OS-conventional config directories; `None` if none could be determined.
 pub fn default_settings_path() -> Option<PathBuf> {
-    ProjectDirs::from("", "", "ottyl").map(|dirs| dirs.config_dir().join("settings.json"))
+    ProjectDirs::from(
+        crate::consts::APP_QUALIFIER,
+        crate::consts::APP_ORGANIZATION,
+        crate::consts::APP_NAME,
+    )
+    .map(|dirs| dirs.config_dir().join(crate::consts::SETTINGS_FILE_NAME))
 }
 
 impl Settings {