kestra-io/kestra · error · IllegalArgumentException

`namespace` and `flowId` should only be set when `executionI

Error message

`namespace` and `flowId` should only be set when `executionId` is set.

What it means

Thrown by PluginUtilsService when executionId is null BUT namespace or flowId is set. The namespace/flowId fields are ONLY meaningful as companions to an explicit executionId; without executionId the task always operates on the current execution (sourced from flowInfo), so setting namespace/flowId is contradictory and rejected. Mirrors error 33 — together they enforce the all-or-nothing pairing of namespace/flowId with executionId.

Source

Thrown at core/src/main/java/io/kestra/core/models/tasks/runners/PluginUtilsService.java:176

        String realFlowId;
        if (executionId != null) {
            realExecutionId = runContext.render(executionId);

            if (namespace != null && flowId != null) {
                realNamespace = runContext.render(namespace);
                realFlowId = runContext.render(flowId);
                // validate that the flow exists: a.k.a access is authorized by this namespace
                runContext.acl().allowNamespace(realNamespace).check();
            } else if (namespace != null || flowId != null) {
                throw new IllegalArgumentException("Both `namespace` and `flowId` must be set when `executionId` is set.");
            } else {
                realNamespace = flowInfo.namespace();
                realFlowId = flowInfo.id();
            }

        } else {
            if (namespace != null || flowId != null) {
                throw new IllegalArgumentException("`namespace` and `flowId` should only be set when `executionId` is set.");
            }
            realExecutionId = (String) new HashMap<>((Map<String, Object>) runContext.getVariables().get("execution")).get("id");
            realNamespace = flowInfo.namespace();
            realFlowId = flowInfo.id();
        }

        return new ExecutionInfo(realTenantId, realNamespace, realFlowId, realExecutionId);
    }

    /**
     * @param render whether to render file contents using Pebble expressions.
     */
    private static void createInputFilesInternal(RunContext runContext, Path workingDirectory, Map<String, String> inputFiles, Map<String, Object> additionalVars, boolean render)
        throws Exception {
        if (inputFiles != null && !inputFiles.isEmpty()) {
            for (String fileName : inputFiles.keySet()) {
                String finalFileName = runContext.render(fileName);

View on GitHub (pinned to 823fada927)

Solutions

If you meant to target a specific execution, also set executionId.
If operating on the current execution, remove namespace and flowId entirely.
Re-read the task property docs to confirm the required combinations.

Example fix

# before
task:
  namespace: "team.prod"
  flowId: "myflow"
  # executionId missing

# after (target current execution): remove namespace/flowId
task: {}
# OR (target specific execution): add executionId
task:
  executionId: "{{ executionId }}"
  namespace: "team.prod"
  flowId: "myflow"

Defensive patterns

Strategy: validation

Validate before calling

if (executionId == null && (namespace != null || flowId != null)) {
    throw new IllegalArgumentException("`namespace` and `flowId` should only be set when `executionId` is set.");
}

Type guard

function isExecutionRefValid(o: { executionId?: string; namespace?: string; flowId?: string }): boolean {
  if (!o.executionId) return !o.namespace && !o.flowId;
  return (!o.namespace && !o.flowId) || (!!o.namespace && !!o.flowId);
}

Try / catch

try {
    PluginUtilsService.executionInfo(runContext, executionId, namespace, flowId);
} catch (IllegalArgumentException e) {
    log.error("namespace/flowId set without executionId: {}", e.getMessage());
}

Prevention

Omit namespace and flowId when targeting the current execution.
Document the all-or-nothing rule for execution references.

When it happens

Trigger: A task sets namespace/flowId but omits executionId; operator assumes namespace/flowId select a target flow without an execution reference.

Common situations: Misunderstanding that namespace/flowId are subordinate to executionId; leftover config from a different task shape.

Related errors

AI-assisted analysis of kestra-io/kestra@823fada927 (2026-08-14). Data as JSON: /api/errors/8fce8ac2b6a522e4. Report an issue: GitHub.