flowable/flowable-engine · warning

Error while generating decision requirements diagram, image…

Error message

Error while generating decision requirements diagram, image will not be stored in repository

What it means

A WARN-level message logged by DecisionRequirementsDiagramHelper.createDiagramForDecision when any Throwable occurs while generating the DRD (decision requirements diagram) PNG during DMN deployment. The deployment itself succeeds and the decision remains executable; only the generated diagram resource is not stored in the repository (the method returns null).

Solutions

1. Install AWT/font support in the runtime environment (e.g. fontconfig + DejaVu fonts in the container) and re-deploy.
2. Inspect the nested Throwable in the log to fix the actual root cause (e.g. correct the DMNDI section of the .dmn XML).
3. If diagrams are not needed, ignore the warning safely — deployment and execution are unaffected.
4. Remove or fix invalid <DMNDI> elements, or regenerate the DMN file with a modeler that emits valid DI.

Example fix

// Dockerfile before (minimal JRE)
FROM eclipse-temurin:17-jre
// after (fonts for AWT diagram generation)
FROM eclipse-temurin:17-jre
RUN apt-get update && apt-get install -y fontconfig fonts-dejavu-core && rm -rf /var/lib/apt/lists/*

try { java.awt.GraphicsEnvironment.getLocalGraphicsEnvironment(); } catch (Throwable t) { /* headless/AWT unavailable: expect no diagram */ }

try { repositoryService.createDeployment().addClasspathResource("decision.dmn").deploy(); } catch (Exception e) { log.error("DMN deployment failed", e); } // diagram loss is only a WARN inside deployment; check resource==null via repository queries

When it happens

Trigger: Calling the DMN deployer (e.g. RepositoryService.createDeployment().deploy() on a .dmn file, or Spring auto-deployment) when diagram generation throws: headless JVM without fonts/AWT classes, invalid DI (diagram interchange) sections in the DMN XML, or a NullPointerException from missing decision/DI metadata.

Common situations: Running in a minimal Docker image without fontconfig/AWT libraries; DMN XML with missing or malformed DMNDI diagram/shape elements; custom classloaders that cannot load icon resources; any JVM where java.awt initialization fails.

Understand the failure class

Background: 'Could not be found', 'does not exist', 'not found in database': the resource-not-found family when an ID, slug, key, or URI lookup comes back empty — this error's family across 20 libraries.

Related errors

• Error while generating case diagram, image will not be…
• byte array for resource
• Could not find deployment with id
• Could not find deployment with id
• could not get byte array from resource

AI-assisted analysis of flowable/flowable-engine@d6d39ce1c6 (2026-09-11). Data as JSON: /api/errors/f91e572f15cd3054. Report an issue: GitHub.

Appendix: source

Thrown at modules/flowable-dmn-engine/src/main/java/org/flowable/dmn/engine/impl/deployer/DecisionRequirementsDiagramHelper.java:65

        try {
            byte[] diagramBytes = IoUtil.readInputStream(
                    dmnEngineConfiguration.getDecisionRequirementsDiagramGenerator().generateDiagram(dmnDefinition, "png",
                            dmnEngineConfiguration.getDecisionFontName(),
                            dmnEngineConfiguration.getLabelFontName(),
                            dmnEngineConfiguration.getAnnotationFontName(),
                            dmnEngineConfiguration.getClassLoader()), null);
            String diagramResourceName = ResourceNameUtil.getDecisionRequirementsDiagramResourceName(
                    decision.getResourceName(), decision.getKey(), "png");

            resource.setName(diagramResourceName);
            resource.setBytes(diagramBytes);
            resource.setDeploymentId(decision.getDeploymentId());

            // Mark the resource as 'generated'
            resource.setGenerated(true);

        } catch (Throwable t) { // if anything goes wrong, we don't store the image (the decision will still be executable).
            LOGGER.warn("Error while generating decision requirements diagram, image will not be stored in repository", t);
            resource = null;
        }

        return resource;
    }

    protected DmnResourceEntity createResourceEntity() {
        return CommandContextUtil.getDmnEngineConfiguration().getResourceEntityManager().create();
    }

    public boolean shouldCreateDiagram(DecisionEntity decision, EngineDeployment deployment) {
        if (deployment.isNew() && decision.hasGraphicalNotation()
                && CommandContextUtil.getDmnEngineConfiguration().isCreateDiagramOnDeploy()) {

            // If the 'getDecisionRequirementsDiagramResourceNameFromDeployment' call returns null, it means
            // no diagram image for the decision was provided in the deployment resources.
            return ResourceNameUtil.getDecisionRequirementsDiagramResourceNameFromDeployment(decision, deployment.getResources()) == null;
        }

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