Driller

A fast, lightweight HTTP load testing tool written in Rust with an Ansible-inspired YAML syntax. Friendly fork of fcsonline/drill -- see FORK.md for background.

Quick start

cargo install driller

driller run http://localhost:9000/api/users --stats
driller run --benchmark benchmark.yml --stats

Or grab a binary from the latest release.

Example

Create a file called benchmark.yml:

---
concurrency: 4
base: 'http://localhost:9000'
iterations: 5
rampup: 2

plan:
  - name: Fetch users
    request:
      url: /api/users.json

  - name: Fetch account
    request:
      url: /api/account
    assign: account

  - name: Fetch manager
    request:
      url: /api/users/{{ account.body.manager_id }}

  - name: Assert status
    assert:
      key: account.status
      value: 200

  - name: Create order
    request:
      url: /api/orders
      method: POST
      body: '{"user": {{ account.body.id }}}'
      headers:
        Content-Type: application/json

Run it:

driller run --benchmark benchmark.yml --stats

For the full benchmark file syntax, see SYNTAX.md.

Features

• Ad-hoc URL testing -- driller run <URL> sends requests without a benchmark file.
• CLI overrides -- --concurrency, --iterations, --duration, --rampup, and --base-url override values from the benchmark file.
• Duration-based runs -- --duration 30s loops the plan for a fixed wall-clock period instead of a fixed iteration count.
• Concurrency and ramp-up -- control parallel iterations and ramp-up time.
• Dynamic interpolation -- URLs, headers, and bodies can reference variables, CSV data, environment variables, and previous responses.
• Request chaining -- assign response data to variables and use them in later requests.
• Assertions -- validate response status codes and body values inline.
• Multiple data sources -- loop over inline lists, ranges, CSV files, or included YAML files.
• Statistics -- mean, median, standard deviation, and p99/p99.5/p99.9 latency percentiles.
• Benchmark comparison -- compare runs against a saved report with configurable thresholds.
• Tags -- run or skip specific plan items by tag.
• All HTTP methods -- GET, POST, PUT, PATCH, DELETE, HEAD.
• Cookie propagation -- session cookies carry across requests automatically.
• Shell execution -- run external commands and capture output into variables.

CLI reference

driller run -- execute a benchmark or ad-hoc request

Usage: driller run [OPTIONS] [URL]

Arguments:
  [URL]  Target URL for ad-hoc testing (creates a synthetic GET request)

Run-specific options:
  -u, --base-url <URL>           Override the base URL from the benchmark file
  -p, --concurrency <N>          Number of concurrent requests [default: 1]
  -i, --iterations <N>           Number of iterations [default: 1]
  -d, --duration <DURATION>      Run for a fixed wall-clock duration (e.g. "30s", "5m", "1h")
  -e, --rampup <N>               Ramp-up time in seconds [default: 0]

--duration and --iterations are mutually exclusive. When neither is given, the default is 1 iteration.

When both a URL and --benchmark are provided, the benchmark file supplies the plan and the URL sets the base URL.

Examples

# Quick smoke test
driller run http://localhost:3000/health

# 10 concurrent users, 100 total iterations
driller run http://localhost:3000/api -p 10 -i 100 --stats

# Run a benchmark file for 60 seconds with overridden concurrency
driller run --benchmark bench.yml --duration 60s --concurrency 20 --stats

# Override the base URL to point at staging
driller run --benchmark bench.yml --base-url http://staging:3000 --stats

Global options

These flags work with both driller run and the legacy driller --benchmark form:

  -b, --benchmark <FILE>        Sets the benchmark file
  -s, --stats                   Shows request statistics
  -r, --report <FILE>           Sets a report output file
  -c, --compare <FILE>          Sets a comparison baseline file
  -t, --threshold <MS>          Threshold in ms for comparison
      --relaxed-interpolations  Do not panic on missing interpolations
      --no-check-certificate    Disables SSL certificate verification
      --tags <TAGS>             Comma-separated tags to include
      --skip-tags <TAGS>        Comma-separated tags to exclude
      --list-tags               List all benchmark tags
      --list-tasks              List benchmark tasks (applies tag filters)
  -q, --quiet                   Disables output
  -o, --timeout <SECONDS>       Request timeout in seconds [default: 10]
  -n, --nanosec                 Shows statistics in nanoseconds
  -v, --verbose                 Toggle verbose output
  -h, --help                    Print help
  -V, --version                 Print version

Configuration precedence

When using driller run with a benchmark file, values are resolved in three layers (last wins):

1. Defaults -- concurrency=1, iterations=1, rampup=0
2. Benchmark YAML -- values from the file override defaults
3. CLI flags -- --concurrency, --iterations, etc. override the file

Building from source

git clone https://github.com/zoosky/driller.git && cd driller
cargo build --release
./target/release/driller --benchmark benchmark.yml --stats

OpenSSL dependency

Driller links against OpenSSL for TLS. Install the development headers for your platform:

Testing locally

The example/ directory contains a small Node.js server and sample benchmark files. See the example README for setup instructions.

Disclaimer: do not run intensive benchmarks against production environments.

Contributing

Pull requests are welcome. See FORK.md for the relationship to upstream and the goals of this fork.

License

GPL-3.0-or-later. See LICENSE for the full text.