This seems to be something specific for your environment. I tested with:
``` $var(fmt) = '{"srcip": "$si", "rcvip": "$Ri"}'; pv_evalx("$var(msg)", "$var(fmt)"); xlog("==== fmt: $var(fmt)\n"); xlog("==== msg: $var(msg)\n"); ```
And I got:
``` 2(4083) ERROR: <script>: ==== fmt: {"srcip": "$si", "rcvip": "$Ri"} 2(4083) ERROR: <script>: ==== msg: {"srcip": "127.0.0.1", "rcvip": "127.0.0.1"} ```
Can you test if pv_evalx() is successful? Did you set any pv-related global parameters?