apache/skywalking · error · IllegalArgumentException

compile_failed

compile_failed

Error message

LAL YAML parse failure while extracting outputType: {t.getMessage()}

What it means

DeltaClassifier.extractLalOutputTypes wraps any Throwable thrown while snakeyaml-parsing LAL content into an LALConfigs object during outputType extraction. The classifier runs on the hot-update path to diff old vs new rule content, so a YAML that does not conform to the LAL schema (wrong key names, bad indentation, non-scalar where a scalar is expected) fails here with code compile_failed. The original parser message and cause are preserved, so the real YAML error is always the nested cause.

Source

Thrown at oap-server/server-admin/runtime-rule/src/main/java/org/apache/skywalking/oap/server/receiver/runtimerule/apply/DeltaClassifier.java:369

    private static Map<String, String> lalRuleOutputTypes(final String content) {
        if (content == null || content.isEmpty()) {
            return Collections.emptyMap();
        }
        try (StringReader r = new StringReader(content)) {
            final LALConfigs configs = new Yaml().loadAs(r, LALConfigs.class);
            if (configs == null || configs.getRules() == null) {
                return Collections.emptyMap();
            }
            final Map<String, String> out = new LinkedHashMap<>();
            for (final LALConfig c : configs.getRules()) {
                final String layer = c.getLayer() == null || c.getLayer().isEmpty()
                    ? "auto" : c.getLayer();
                out.put(layer + ":" + c.getName(), c.getOutputType());
            }
            return Collections.unmodifiableMap(out);
        } catch (final Throwable t) {
            throw new IllegalArgumentException(
                "LAL YAML parse failure while extracting outputType: " + t.getMessage(), t);
        }
    }

    private static String nullToEmpty(final String s) {
        return s == null ? "" : s;
    }

    public static Set<String> enumerateLalRuleKeys(final String content) {
        final Set<String> out = new LinkedHashSet<>();
        if (content == null || content.isEmpty()) {
            return Collections.unmodifiableSet(out);
        }
        try (StringReader r = new StringReader(content)) {
            final LALConfigs configs = new Yaml().loadAs(r, LALConfigs.class);
            if (configs == null || configs.getRules() == null) {
                return Collections.unmodifiableSet(out);
            }

View on GitHub (pinned to 102af09b4a)

Solutions

1. Read the nested cause message — snakeyaml names the exact line/column of the syntax or mapping error; fix that spot in the LAL content
2. Validate the content locally with the same shape: new Yaml().loadAs(new StringReader(content), LALConfigs.class) must return rules with name+layer before submitting
3. Check you targeted the right catalog: LAL schema (rules with name/layer/outputType) vs MAL schema (metricPrefix/metricsRules) are not interchangeable
4. If hot-updating a rule that previously worked, diff against the last-known-good content to find the edit that broke the YAML

Example fix

# before
rules:
  - name: my-rule
    layer: general
      outputType: "log"   # bad indent under layer
# after
rules:
  - name: my-rule
    layer: general
    outputType: "log"

LALConfigs probe = null;
try (StringReader r = new StringReader(content)) {
    probe = new Yaml().loadAs(r, LALConfigs.class);
}
if (probe == null || probe.getRules() == null) throw new ClientSideValidationException("not a LAL document");
for (final LALConfig c : probe.getRules()) {
    if (c.getName() == null || c.getName().isEmpty()) throw new ClientSideValidationException("rule without name");
}

catch (IllegalArgumentException e) { if (e.getMessage().startsWith("LAL YAML parse failure while extracting outputType")) surface the cause's line/column to the editor; else rethrow; }

When it happens

Trigger: Submitting a runtime-rule update whose content is invalid LAL YAML — e.g. 'exp:' misspelled, a tab used for indentation, a list where LALConfigs expects a map, or content that is not YAML at all (plain text / a MAL document passed as catalog 'lal'). Any DeltaClassifier.classifyLal call on such content throws IllegalArgumentException before classification completes.

Common situations: Copy-pasting a MAL .yaml into the LAL catalog when uploading via the runtime-rule API; Hand-editing LAL rules in an editor that converts spaces to tabs; Truncation of large rule bodies by a proxy or CLI tool, leaving unterminated YAML; Migrating LAL rules from an older schema where keys were renamed

Related errors

• LAL YAML parsed to empty/malformed — no rules list in {sourc
• LAL YAML parse failure for {sourceName}
• LAL compile failed for rule '{name}' in {sourceName}
• LAL register failed for rule '{ruleName}' in {sourceName}
• YAML parsed to null — empty or malformed rule file: {sourceN

AI-assisted analysis of apache/skywalking@102af09b4a (2026-08-14). Data as JSON: /api/errors/fc3b305071cd2aef. Report an issue: GitHub.