mirrors/linera-protocol

[frontport] Fix proxy metrics cardinality explosion from bot traffic (#5600)

Motivation

The tower middleware added in #5534 extracts method_name from the URI path using rsplit('/') for per-method success/error metrics. This works correctly for gRPC requests, but internet-facing proxies also receive bot/scanner traffic (.env, wp-login.php, etc.). Each unique probe path creates a permanent new Prometheus time series, causing unbounded label cardinality.

On a test network, 325+ unique method_name label values were observed within hours, all from bot probes.

This was discovered and fixed during the backport to testnet_conway (#5591).

Proposal

Replace the naive rsplit('/') extraction with a check for the gRPC URI pattern. gRPC paths have the form /{package}.{Service}/{Method} — the first segment always contains a dot. Non-gRPC requests are bucketed as non_grpc instead of recording the raw path, keeping label cardinality bounded to the number of actual gRPC methods.

Test Plan

CI
Verified on a test network (andrtest-conway): after deploying, proxy error metrics collapsed from 325+ unique labels to just 2 (non_grpc + one straggler from before the fix). gRPC success metrics correctly show PascalCase method names (HandleBlockProposal, HandleLiteCertificate, etc.).

Linera is a decentralized blockchain infrastructure designed for highly scalable, secure, low-latency Web3 applications.

Documentation

Visit our developer page and read our whitepaper to learn more about the Linera protocol.

Repository Structure

The main crates and directories of this repository can be summarized as follows: (listed from low to high levels in the dependency graph)

linera-base Base definitions, including cryptography.
linera-version A library to manage version info in binaries and services.
linera-views A library mapping complex data structures onto a key-value store. The corresponding procedural macros are implemented in linera-views-derive.
linera-execution Persistent data and the corresponding logic for runtime and execution of Linera applications.
linera-chain Persistent data and the corresponding logic for chains of blocks, certificates, and cross-chain messaging.
linera-storage Defines the storage abstractions for the protocol on top of linera-chain.
linera-core The core Linera protocol, including client and server logic, node synchronization, etc.
linera-rpc Defines the data-type for RPC messages (currently all client ↔ proxy ↔ chain ↔ chain interactions), and track the corresponding data schemas.
linera-client Library for writing Linera clients. Used for the command-line client and the node service in linera-service, as well as the Web client in linera-web.
linera-service Executable for clients (aka CLI wallets), proxy (aka validator frontend) and servers.
linera-sdk The library to develop Linera applications written in Rust for the Wasm virtual machine. The corresponding procedural macros are implemented in linera-sdk-derive.
examples Examples of Linera applications written in Rust.

Prerequisites

See INSTALL.md for software requirements to develop in this repo.

Quickstart with the Linera CLI tool

The following commands set up a local test network and run some transfers between the microchains owned by a single wallet.

# Make sure to compile the Linera binaries and add them in the $PATH.
# cargo build -p linera-storage-service -p linera-service --bins
export PATH="$PWD/target/debug:$PATH"

# Import the optional helper function `linera_spawn`.
source /dev/stdin <<<"$(linera net helper 2>/dev/null)"

# Run a local test network with the default parameters and a number of microchains
# owned by the default wallet. This also defines `LINERA_TMP_DIR`.
linera_spawn \
linera net up --with-faucet --faucet-port 8080

# Remember the URL of the faucet.
FAUCET_URL=http://localhost:8080

# If you're using a testnet, start here and run this instead:
#   LINERA_TMP_DIR=$(mktemp -d)
#   FAUCET_URL=https://faucet.testnet-XXX.linera.net  # for some value XXX

Enable logs for user applications:

export LINERA_APPLICATION_LOGS=true

Set the path of the future wallet:

export LINERA_WALLET="$LINERA_TMP_DIR/wallet.json"
export LINERA_KEYSTORE="$LINERA_TMP_DIR/keystore.json"
export LINERA_STORAGE="rocksdb:$LINERA_TMP_DIR/client.db"

# Initialize a new user wallet.
linera wallet init --faucet $FAUCET_URL

# Request chains.
INFO1=($(linera wallet request-chain --faucet $FAUCET_URL))
INFO2=($(linera wallet request-chain --faucet $FAUCET_URL))
CHAIN1="${INFO1[0]}"
ACCOUNT1="${INFO1[1]}"
CHAIN2="${INFO2[0]}"
ACCOUNT2="${INFO2[1]}"

# Show the different chains tracked by the wallet.
linera wallet show

# Query the chain balance of some of the chains.
linera query-balance "$CHAIN1"
linera query-balance "$CHAIN2"

# Transfer 10 units then 5 back.
linera transfer 10 --from "$CHAIN1" --to "$CHAIN2"
linera transfer 5 --from "$CHAIN2" --to "$CHAIN1"

# Query balances again.
linera query-balance "$CHAIN1"
linera query-balance "$CHAIN2"

# Now let's fund the user balances.
linera transfer 5 --from "$CHAIN1" --to "$ACCOUNT1@$CHAIN1"
linera transfer 2 --from "$ACCOUNT1@$CHAIN1" --to "$ACCOUNT2@$CHAIN2"

# Query user balances again.
linera query-balance "$ACCOUNT1@$CHAIN1"
linera query-balance "$ACCOUNT2@$CHAIN2"

More complex examples may be found in our developer manual as well as the example applications in this repository.

Contributing

We welcome contributions from the community! If you’d like to contribute to the Linera protocol:

Fork the repository
Create a feature branch (git checkout -b feature/amazing-feature)
Commit your changes (git commit -m 'Add some amazing feature')
Push to the branch (git push origin feature/amazing-feature)
Open a Pull Request

For detailed guidelines, see our contribution guide.