AGENTS.md

Repo Role

• Repo: rs-autoscaler
• Language: Rust
• Purpose: Autoscaling service for NVCF monitors function utilization via a timeseries database and adjusts instance counts through the NVCF API.

Architecture

• Scaling loop: Queries utilization metrics, applies per-function scaling policies (static or custom via gRPC), decides desired instance count.
• Discovery: Finds active functions from the timeseries DB (invocations + workers), writes them to Cassandra.
• Policy cache: Fetches per-function scaling configs from a gRPC service, caches with configurable TTL.
• Distributed locking: Cassandra-based locks for coordinating discovery and scaling across replicas.

Key Paths

• crates/server/src/scaling/: scaling logic, policy client/cache, thresholds, stickiness
• crates/server/src/work/: scaling loop, discovery, utilization queries
• crates/server/src/cassandra/: Cassandra client, statements, distributed locks
• crates/server/src/timeseries_db/: timeseries DB client (Thanos/VictoriaMetrics compatible)
• crates/server/src/nvcf_api/: NVCF API client, OAuth2 token client
• crates/server/resources/: YAML config files per environment

Config

• All operational parameters are externalized to YAML settings files with #[serde(default)].
• Environment variable overrides use __ as separator (e.g., SCALING__UTILIZATION_WINDOW_SECONDS=70).
• Secrets are loaded from a JSON file at the path specified by secrets_path in config.

Local Development

# Start dependencies
docker compose -f crates/server/nvcf-service/local_env/docker-compose.yml up -d cassandra victoriametrics

# Copy and fill secrets
cp local_env/secrets/secrets.json.tmpl local_env/vault/secrets.json

# Run with local config
CONFIG=crates/server/resources/settings-local.yaml \
SECRETS_PATH=local_env/vault/secrets.json \
cargo run --bin server -p rs-autoscaler

The cargo run above has the same Bazel-only dependency described under Build & Test, so it does not resolve either. Run the :server Bazel target instead.

Build & Test

crates/server depends on //src/libraries/rust/nvcf-info as a Bazel target only, and cargo does not declare it, so cargo build, cargo clippy, and cargo test fail to resolve it. Build and test with Bazel from the monorepo root:

bazel test //src/control-plane-services/function-autoscaler/crates/server:all

Formatting and advisory checks do not compile the crate, so they still run under cargo:

cargo fmt -p rs-autoscaler
cargo deny check advisories

CI subproject id: function-autoscaler. Follow the root RELEASE.md and docs/dev/github-release-process.md for source versioning and publication handoffs. Inspect .github/workflows/ for current public validation.