Struct Metering 

pub struct Metering { /* private fields */ }

Appends Records to a log file, one JSON object per line.

Implementations

impl Metering

pub fn new(path: &Path) -> Self

Opens a meter writing to path. The file is created on first append.

pub fn path(&self) -> &Path

Where records are appended.

pub fn append(&self, record: &Record)

Appends one record.

Opens the file in append mode per record rather than holding a handle: the file may be rotated or truncated between requests, and a stale handle would silently keep writing to a deleted inode. A write failure cannot fail the request that has already been served, so it is logged to stderr instead of propagated.

pub fn usage_in_month(&self, key_id: &str, month: &str) -> MonthUsage

Counts one key’s usage in one month by reading the log.

A missing log reads as zero usage, and a line that does not parse is skipped: the log is append-only evidence written by this process, so an unreadable line is a torn write, not a record anyone was billed for. The scan is linear in the log’s size — the file rotates with deployment (plan S5) — and only runs for plans that carry a quota, plus the admin keys list.

pub fn query_count_reaches(&self, key_id: &str, month: &str, limit: u64) -> bool

True once the key’s query count in month has reached limit. The scan stops at the limit: the quota check runs per request, and past the limit the exact count no longer matters (a refusal that needs the true number does one full Metering::usage_in_month scan on its own cold path).

pub fn build( &self, key_id: &str, plan: &str, method: &str, path: &str, status: u16, response_bytes: u64, started: SystemTime, ) -> Record

Builds a record with a freshly computed timestamp and duration.

One parameter per record field: the record is the parameter list, and a parameter struct would only rename the same eight values.

Trait Implementations

impl Clone for Metering

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Metering

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.