pentaho/pentaho-kettle · error · KettleConfigException

Unable to get value for expression

Error message

Unable to get value for expression [<expression>] with Ognl

What it means

After successfully compiling an OGNL expression, setOgnlProperty evaluates it via expr.getValue(ognlContext, this). This error is thrown when the expression is syntactically valid but fails during evaluation (OgnlException at getValue time), e.g. it references a null object, an inaccessible method, or a nonexistent property on the target.

Solutions

1. Fix the expression so it only navigates non-null, existing properties/methods of the target object.
2. Add null-safe navigation in the OGNL expression where supported, or ensure the target object is fully initialized before setProperty runs.
3. Test the same expression with ognl.Ognl.getValue(expr, context, target) outside the config pipeline to reproduce and debug.
4. Catch KettleConfigException around config application and log the expression plus target object state.

Example fix

// before
propertySetter.setProperty(obj, "dir", "ognl:user.homeDir.path"); // homeDir may be null

// after
propertySetter.setProperty(obj, "dir", "ognl:user.homeDir != null ? user.homeDir.path : '/tmp'");

Object probe = org.apache.commons.ognl.Ognl.getValue(
  org.apache.commons.ognl.Ognl.parseExpression(expr), ctx, target); // fails fast outside config load

try {
  propertySetter.setProperty(obj, property, "ognl:" + expr);
} catch (KettleConfigException e) {
  LOG.error("OGNL evaluation failed for expression [" + expr + "] on " + obj.getClass(), e);
}

When it happens

Trigger: setProperty(obj, property, "ognl:objRef.someMethod()") where evaluation throws — invoking a method on null, calling a missing method, or triggering an exception inside the OGNL navigation chain.

Common situations: OGNL expressions referencing properties that are null at config-apply time; expressions written against an older object model whose getters no longer exist; security-restricted method invocation failures at runtime.

Related errors

• the ognl, directive need at least 2 parameters: ongl and…
• Unable to parse expression
• A connection of type PALO is expected
• A connection of type PALO is expected
• Caught a number format exception converting minimum length…

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/c1c37519daca1568. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/pentaho/di/core/config/PropertySetter.java:103

    if ( expression.length >= 2 ) {
      OgnlExpression expr = ognlExpressions.get( value );
      if ( expr == null ) {
        synchronized ( ognlExpressions ) {
          try {
            expr = new OgnlExpression( expression[1] );
            ognlExpressions.put( value, expr );

          } catch ( OgnlException e ) {
            throw new KettleConfigException( "Unable to parse expression [" + expression[1] + "] with Ognl", e );
          }
        }
      }

      // evaluate
      try {
        return expr.getValue( octx, this );
      } catch ( OgnlException e ) {
        throw new KettleConfigException(
          "Unable to get value for expression [" + expression[1] + "] with Ognl", e );
      }
    } else {
      throw new KettleConfigException(
        "the ognl, directive need at least 2 parameters: ongl and the expression but "
          + expression.length + " parameters were found in [" + value + "]" );
    }
  }
}

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