Malloy Publisher Server

The Malloy Publisher Server is an Express.js server that provides an API for managing and accessing Malloy data models, packages, and queries

K6 Test Presets

The Malloy Publisher Server includes several K6 test presets to help you test its performance and stability.

Below is a list of the available test presets:

$3

Basic functionality test with minimal load.

- File:
./k6-tests/smoke-test.ts
- Virtual Users: 1
- Duration: 1 minute
- 95th Percentile Response Time: < 500ms
- Error Rate: < 1%

$3

Testing system under normal load.

- File:
./k6-tests/load-test.ts
- Virtual Users: 50
- Duration: 5 minutes
- 95th Percentile Response Time: < 1s
- Error Rate: < 5%

$3

Testing system under extreme load.

- File:

./k6-tests/stress-test.ts

- Virtual Users: 100
- Duration: 10 minutes
- 95th Percentile Response Time: < 2s
- Error Rate: < 10%

$3

Testing system under sudden spikes of load.

- File:
./k6-tests/spike-test.ts
- Stages:
- 2 minutes ramp-up to 100 users
- 1 minute at 100 users
- 2 minutes ramp-down to 0 users
- 95th Percentile Response Time: < 2s
- Error Rate: < 10%

$3

Testing system to find its breaking point.

- File:
./k6-tests/breakpoint-test.ts
- Stages:
- 2 minutes at 50 users
- 2 minutes at 100 users
- 2 minutes at 150 users
- 2 minutes at 200 users
- 2 minutes ramp-down to 0 users
- 95th Percentile Response Time: < 3s
- Error Rate: < 15%

$3

Testing system under sustained load.

- File:
./k6-tests/soak-test.ts
- Virtual Users: 10
- Duration: 1 hour
- 95th Percentile Response Time: < 1s
- Error Rate: < 1%

You can run these presets using the K6 testing tool to ensure your system performs well under different load conditions.

For example, this command will run a smoke test against your localhost:

``sh
k6 run ./k6-tests/smoke-test.ts --env PUBLISHER_URL=http://::1:4000
`

OpenTelemetry Integration

The K6 tests can be configured to export metrics to OpenTelemetry collectors using the experimental OpenTelemetry output. This allows you to integrate K6 metrics with your observability stack.

`sh


Build the publisher server

bun run build

Replace this with an actual OTLP endpoint that you can use

MY_OTLP_ENDPOINT=http://monitoring.myserver.com:4318

Start an instrumented publisher server

OTEL_EXPORTER_OTLP_ENDPOINT=${MY_OTLP_ENDPOINT} PACKAGE_ROOT=./malloy-samples bun start:instrumented

Start an instrumented k6 smoke test

K6_OTEL_HTTP_EXPORTER_ENDPOINT=${MY_OTLP_ENDPOINT} K6_OTEL_GRPC_EXPORTER_INSECURE=true K6_OTEL_METRIC_PREFIX=k6_ k6 run ./k6-tests/smoke-test.ts --env PUBLISHER_URL=http://::1:4000
`

For more information on how to configure OpenTelemetry collectors, please refer to the official documentation: K6 OpenTelemetry Integration

MCP Prompt Capability

Publisher's MCP interface exposes LLM-ready prompts for explaining, generating, translating and summarising Malloy code.

| Prompt ID | Purpose |
| ---------------------------------------------- | ----------------------------------------------------------------- |
| explain-malloy-query@1.0.0 | Explain a Malloy query (sources, transformations, output). |
| generate-malloy-query-from-description@1.0.0 | Create Malloy based on a natural-language goal and model context. |
| translate-sql-to-malloy@1.0.0 | Convert SQL into Malloy using a model for schema reference. |
| summarize-malloy-model@1.0.0 | Summarise a Malloy model (purpose, entities, joins). |

List prompts:

`bash
mcp-client prompts/list
`

Get a prompt:

`bash
mcp-client prompts/get \
--name explain-malloy-query@1.0.0 \
--arguments '{"query_code":"from flights"}'
`

These calls return messages` ready for your LLM chat completion.