ic-metrics

Allocation-free, dependency-free measurement arithmetic.

The no_std library exports record_sample for consumer-owned count/total fields and MeasurementSummary for samples, total, latest and maximum. Zero is a valid observation; an empty summary has no latest or maximum value. Count and total saturate independently. Consumers establish units, identity and reset boundaries before comparing observations; saturated totals cannot supply exact interval arithmetic.

use ic_metrics::MeasurementSummary;

let mut summary = MeasurementSummary::EMPTY;
assert_eq!(summary.latest(), None);
summary.record(0);
assert_eq!(summary.samples(), 1);
assert_eq!(summary.latest(), Some(0));

Known downstream consumers are IcyDB, Canic, ic-timers and ic-backup. Their attribution, registries, callback roles, replication, persistence and reporting remain local. ic-backup's released 0.3.7 host integration uses arithmetic-only summaries for local durations in nanoseconds and prepared chunk sizes in bytes; it enables no IC reader and its diagnostics establish no IC instruction or cycle cost. The crate has no global consumer registry, stable-memory allocation or endpoints. Consumers own their summary instances, labels and persistence policy. The extraction contract records scope and evidence.

The published 0.2.0 hard cut removes the ic feature and call_context_instructions. Platform reads belong in consumer adapters: IcyDB and Canic use ic_cdk::api::call_context_instruction_counter(); IC Timers uses its existing ic0::performance_counter(1) binding. Both read counter 1. Consumers own target gating, native handling, call-context identity and attribution. IcyDB's inclusive overlapping spans and Canic's exclusive endpoint accounting remain different consumer contracts.

The latest published package is 0.2.0. IC Timers 0.14.0 uses the arithmetic-only registry package. IcyDB and Canic's current worktrees select that timer release and ic-metrics 0.2.0; their owning release/CI qualification remains separate. IC Backup 0.3.9 still selects arithmetic-only ic-metrics 0.1.9 and needs no reader change. Consumers exposing MeasurementSummary in public APIs must coordinate their 0.2 dependency identity. Stored data, reports and endpoints are unchanged. Historical reader execution remains in the source-bound evidence and tagged releases; current CI qualifies arithmetic and repository tooling.

Measuring cost

Measure raw canister Wasm bytes, IC instructions and actual cycle charges separately. The shared arithmetic allocates nothing; labels, map updates and report encoding are consumer costs. Build profiles belong to the consumer workspace. The performance audit records historical compiler checks and size/instruction/cycle comparisons for the retired reader test canister, with their workload limits. It does not establish consumer savings.

The separate consumer lookup measurements cover IcyDB and Canic's borrowed-key changes. Their isolated IC fixtures show lower instruction work and cycle charges for repeated keys, but higher costs for first insertions. Use the recorded workload and artifact identities when assessing those consumer changes; upgrading ic-metrics alone does not apply them.

Development

Install rustup, Git, GNU Make, Bash 3.2 or newer and a SHA-256 utility. The pinned toolchain is Rust 1.99.0 and the MSRV is 1.88.0. Install wasm32-unknown-unknown for Wasm checks. make help lists focused commands; select named tests during implementation. Full make ci requires an explicit request outside configured CI.

Install the pinned manifest formatter during developer setup:

cargo install cargo-sort --version 2.1.4 --locked
make install-hooks

make fmt sorts every workspace manifest before Rust formatting. make fmt-check checks both without changing files; CI installs the same pinned formatter. Run make install-hooks once per clone and after updating shared tooling. The repository-local pre-commit hook formats the staged snapshot, refreshes selected files, rejects partial staging and preserves unrelated working edits. It refuses to replace existing hook installations. make hook-check exercises these contracts in scratch repositories without creating commits.

See agent rules, host support and the current handoff. Reviewed shared tooling is vendored; normal checks and release scripts need no Shared Tooling sibling checkout.

Prepare the reviewed local executables explicitly:

make install-tools
make tools-check
export PATH="$PWD/.tools/host/bin:$PWD/.tools/ic/bin:$PATH"

The setup installs jq and Mike Farah yq plus Quill, ICP CLI, didc, ic-wasm, PocketIC and Binaryen under this checkout's .tools/. It retains previous and failed candidates. tools-check is offline; ordinary validation never installs tools. System bootstrap packages and installation behavior are documented in local setup.

make check-pins checks dependency and workflow declarations offline using Git and the prepared local parsers. Their single reviewed pin owner is ci/tool-versions.env; IC executable pins live in ci/ic-tools.tsv. Local setup and focused commands are in host support. The library has no Cargo dependencies. Tracked lockfiles preserve workspace identity. Dependency changes must prepare every affected independent workspace graph before release validation. Checks never upgrade dependencies or install tools implicitly.

Releases and adoption

The public repository is dragginzgame/ic-metrics. The changelog preserves the initial 0.1.0 scaffold, the 0.1.1 arithmetic release and later tooling releases. ic-metrics 0.2.0 is published on crates.io with tag v0.2.0. Declare the published release in the consumer's root dependency catalog:

[workspace.dependencies]
ic-metrics = "0.2"

Members inherit with ic-metrics = { workspace = true }. Published consumers must resolve the registry package rather than require a sibling checkout. The adoption issue links each consumer's integration evidence. Native qualification is recorded against its actual revision in the host record.

Maintainer-owned make release-patch, release-minor and release-major use the same reviewed workflow, with RELEASE_REMOTE=origin and RELEASE_BRANCH=main. They require cargo-edit (cargo set-version) and cargo-sort 2.1.4, run the complete offline gate, prepare only Cargo metadata and release notes, commit, tag and atomically push. They do not publish the crate. Normal release targets reconcile an interrupted release at its saved commit. Newer committed fixes or a different requested increment then receive fresh preflight and full validation before the next release is prepared. Failed validation logs remain under the Git directory's release-state/validation-failures/; earlier attempts are retained. make release-resume VERSION=X.Y.Z remains available for explicit selection; identity, payload and destination conflicts stop recovery.

For a subsequent committed package release, the maintainer can run:

make publish-check
make publish

publish-check delegates to Cargo's dry run. publish uploads only ic-metrics to crates.io, using the existing package version, locked dependencies and normal Cargo credential setup (cargo login --registry crates-io). Both retain Cargo's package verification and dirty-tree rejection. Publication creates no Git commit or tag, does not bump versions and preserves build artifacts. See Cargo's publication documentation.

cargo package -p ic-metrics --locked --offline --allow-dirty prepares and verifies a local development archive without uploading it. The package includes the canonical MIT license text, source and this README; documentation links resolve to the public repository. The manifest restricts publication to crates.io.