Download Center#

Everything here is permanent. A released schema URL keeps serving the same bytes forever — see versioning and immutability.

Schemas#

Point your editor at the schema for completion and inline validation:

<harness xmlns="https://harnessxml.com/spec/1.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="https://harnessxml.com/spec/1.0
                             https://harnessxml.com/schema/v1.0/harnessxml-1.0.xsd"
         id="my_workflow" specVersion="1.0">

Validate from the command line with any XSD-capable tool:

# xmllint
xmllint --noout --schema harnessxml-1.0.xsd my_workflow.hxml

# python, standard tooling
python3 -c "from lxml import etree; \
  etree.XMLSchema(etree.parse('harnessxml-1.0.xsd')).assertValid(etree.parse('my_workflow.hxml'))"

The XSD is normative for structure only. Rules XSD 1.0 cannot express — acyclicity, reachability, expression well-formedness, retry-on-non-idempotent — are normative in the specification text and carry HX-nnnn codes. A document that passes the schema is not necessarily valid HarnessXML.

File extension and media type#

Neither affects validity — an implementation must recognise a HarnessXML document from its root element and namespace, never from its filename. The extension exists so editors, diff tools and operators recognise a workflow at a glance.

Three names appear around HarnessXML, at three layers. Only .hxml crosses the boundary between tools:

Rumima Enterprise Studio  →  .rmmx  →  .hxml  →  any conforming runtime  →  execution

A .rmmx document contains .visml markup, which embeds a complete HarnessXML document. Export lifts that element out; import wraps it. Nothing is translated, so nothing is lost in translation.

The dependency runs one way only. HarnessXML must be fully definable, validatable and executable without reference to .visml, .rmmx or any other host format. It is not a subset of, profile of, or extension of any of them — it is an independent specification that a host document happens to contain, exactly as an HTML page may contain an SVG document. No conforming implementation is ever expected to read .rmmx or .visml. See §2.9.1.

Example documents#

Real, complete, schema-valid documents. Each is also a conformance fixture, so they cannot rot without CI noticing.

Authored as visual maps#

The same harnesses as Rumima .rmmx documents, with screenshots of the actual application rendering them:

Opening them needs Rumima; reading them does not — every node's description carries its HarnessXML fragment. The .hxml these export to is vendor-neutral and runs on any conforming runtime.

Reference implementation#

Apache-2.0. Parser, validator and execution model in Rust, plus the harnessxml CLI.

git clone https://gitlab.com/visml/harnessxml
cd harnessxml/reference-runtime
cargo build --release

harnessxml validate workflow.hxml                    # schema + specification rules
harnessxml graph    workflow.hxml                    # the resolved execution graph
harnessxml explain  workflow.hxml                    # what each node waits for
harnessxml run      workflow.hxml                    # EXECUTE it
harnessxml run      workflow.hxml --scenario s.txt --trace

The executor implements the full model of chapters 5–8: the lifecycle state machine, join policies, guards, decisions in document order, the four loop kinds with maxIterations enforced, retry policies with backoff, and compensation unwinding in reverse completion order. Because impl is opaque, node outcomes come from a scenario script, which is what makes a run — and therefore a conformance trace — reproducible.

Its job is to be unambiguous rather than fast — every normative rule has running code and a test behind it.

SDKs#

Language bindings for building, reading and validating documents.

Planned means not written. Those rows are listed so the intended surface is public and nobody duplicates work by accident — not to suggest something exists that you can install today.

An SDK is marked available only when it passes the conformance suite. All three that are, do: Rust, Python and Go each accept every valid fixture and reject every invalid one with the same HX-nnnn code. Three independent codebases in three languages reaching identical verdicts is the best evidence available that the specification is precise enough to implement from.

Conformance suite#

The fixtures that define conformance: documents that must be accepted, documents that must be rejected with a specified error code, and execution traces that must match.

git clone https://gitlab.com/visml/harnessxml
python3 harnessxml/conformance/validate.py

Self-certification is the default — run it, publish your results, state your level. See conformance.

Licensing#

See licensing for what that means in practice.