apache/skywalking · critical · ModuleStartException

Layer {} has already set {} rule.

Error message

Layer {} has already set {} rule.

What it means

Thrown during static rule load when two rules targeting the SAME Layer share the same name: per-layer DSL maps (initDsls keyed by Layer) reject the second registration of an identical name. This is the layer-scoped twin of the auto-layer duplicate-name error — the same name in two different layers is fine, but not twice within one layer.

Source

Thrown at oap-server/analyzer/log-analyzer/src/main/java/org/apache/skywalking/oap/log/analyzer/v2/provider/log/listener/LogFilterListener.java:258

         */
        public void loadStaticRules() throws Exception {
            final Map<Layer, Map<String, DSL>> initDsls = new HashMap<>();
            final Map<String, DSL> initAutoDsls = new HashMap<>();
            final List<LALConfig> configList = LALConfigs.load(analyzerConfig.getLalPath(), analyzerConfig.lalFiles())
                                                         .stream()
                                                         .flatMap(it -> it.getRules().stream())
                                                         .collect(Collectors.toList());
            for (final LALConfig c : configList) {
                final CompiledLAL compiled = compile(c);
                if (compiled.layer == null) {
                    if (initAutoDsls.put(c.getName(), compiled.dsl) != null) {
                        throw new ModuleStartException(
                            "Auto-layer rules have duplicate name: " + c.getName());
                    }
                } else {
                    final Map<String, DSL> layerDsls = initDsls.computeIfAbsent(compiled.layer, k -> new HashMap<>());
                    if (layerDsls.put(c.getName(), compiled.dsl) != null) {
                        throw new ModuleStartException(
                            "Layer " + compiled.layer.name() + " has already set " + c.getName() + " rule.");
                    }
                }
                // Publish per-rule debug holder into the dsl-debugging registry. sourceName, not
                // sourcePath: both routes derive it through LALConfigs.stampSource, so a
                // runtime-rule replace puts over the static binding without orphaning it.
                LalStaticBindingHook.publish(c.getSourceName(), c.getName(), compiled.dsl.getExpression());
            }
            // Publish: readers from now on see the startup-complete registry.
            this.dsls = initDsls;
            this.autoDsls = initAutoDsls;
        }

        /**
         * Compile a single LALConfig into a runnable {@link DSL}. Used by both the startup
         * constructor and the runtime-rule hot-update path (LalFileApplier).
         */
        public CompiledLAL compile(final LALConfig c) throws ModuleStartException {

View on GitHub (pinned to 102af09b4a)

Solutions

1. Rename the duplicate rule within that layer
2. If the rules genuinely target different layers, verify both layer: declarations resolve to distinct Layer values
3. Delete the stale copy if the file was duplicated wholesale

Example fix

# before: two entries with layer: MESH named 'envoy-als'
# after: rename the second
ruleName: envoy-als-custom

# Detect duplicate names within a layer:
#   awk '/^layer:/{L=$2} /^ruleName:/{print L, $2}' lal/*.yaml | sort | uniq -d

When it happens

Trigger: Two rules both declaring layer: MESH (or resolved to the same layer) with identical ruleName; copy-pasting an envoy-als style rule and keeping the name; a layerDefinitions inline entry plus an explicit layer: that resolve to the same Layer object.

Common situations: Extending a shipped per-layer rule file (envoy-als.yaml etc.) by duplicating an entry and editing only the body; merging contributed rule files for the same layer.

Related errors

• Auto-layer rules have duplicate name: {name}
• LAL rule {ruleName} layerDefinitions entry rejected: {def}
• Failed to load static LAL rules.
• Failed to compile LAL expression: {dsl}
• Failed to load LAL config rules

AI-assisted analysis of apache/skywalking@102af09b4a (2026-08-14). Data as JSON: /api/errors/cad2f9a9873e8b25. Report an issue: GitHub.