run http filter example error, How to solve？

[ilib0x00000000]

[2020-05-27 10:41:10.052][457426][debug][config] [external/envoy/source/extensions/filters/network/http_connection_manager/config.cc:446] http filter #0
[2020-05-27 10:41:10.052][457426][debug][config] [external/envoy/source/extensions/filters/network/http_connection_manager/config.cc:447] name: sample
[2020-05-27 10:41:10.052][457426][debug][config] [external/envoy/source/extensions/filters/network/http_connection_manager/config.cc:454] config: {}

[2020-05-27 10:41:10.052][457426][debug][misc] [external/envoy/source/common/protobuf/utility.cc:255] Proto validation error; throwing Proto constraint validation failed (DecoderValidationError.Key: ["value length must be at least " '\x01' " bytes"]):
[2020-05-27 10:41:10.053][457426][debug][init] [external/envoy/source/common/init/watcher_impl.cc:27] Listener-local-init-watcher 4628fb28-aad4-441e-bdb1-1e8de7e423e8 destroyed
[2020-05-27 10:41:10.053][457426][debug][init] [external/envoy/source/common/init/watcher_impl.cc:27] init manager Listener-local-init-manager 4628fb28-aad4-441e-bdb1-1e8de7e423e8 14773217957741281905 destroyed
[2020-05-27 10:41:10.053][457426][debug][init] [external/envoy/source/common/init/target_impl.cc:32] target Listener-init-target 4628fb28-aad4-441e-bdb1-1e8de7e423e8 destroyed
[2020-05-27 10:41:10.055][457426][critical][main] [external/envoy/source/server/server.cc:95] error initializing configuration 'envoy.yaml': Proto constraint validation failed (DecoderValidationError.Key: ["value length must be at least " '\x01' " bytes"]):
[2020-05-27 10:41:10.055][457426][debug][init] [external/envoy/source/common/init/watcher_impl.cc:27] ClusterImplBase destroyed
[2020-05-27 10:41:10.055][457426][debug][init] [external/envoy/source/common/init/watcher_impl.cc:27] init manager Cluster ping-service destroyed
[2020-05-27 10:41:10.055][457426][debug][grpc] [external/envoy/source/common/grpc/google_async_client_impl.cc:35] Joining completionThread
[2020-05-27 10:41:10.055][457433][debug][grpc] [external/envoy/source/common/grpc/google_async_client_impl.cc:68] completionThread exiting
[2020-05-27 10:41:10.055][457426][debug][grpc] [external/envoy/source/common/grpc/google_async_client_impl.cc:37] Joined completionThread
[2020-05-27 10:41:10.056][457426][debug][upstream] [external/envoy/source/common/upstream/cluster_manager_impl.cc:942] shutting down thread local cluster manager
[2020-05-27 10:41:10.056][457426][info][main] [external/envoy/source/server/server.cc:606] exiting
[2020-05-27 10:41:10.056][457426][debug][main] [external/envoy/source/common/access_log/access_log_manager_impl.cc:16] destroying access logger /dev/stdout
[2020-05-27 10:41:10.057][457426][debug][main] [external/envoy/source/common/access_log/access_log_manager_impl.cc:16] destroying access logger /dev/null
[2020-05-27 10:41:10.057][457426][debug][main] [external/envoy/source/common/access_log/access_log_manager_impl.cc:19] destroyed access loggers
[2020-05-27 10:41:10.059][457426][debug][init] [external/envoy/source/common/init/watcher_impl.cc:27] init manager Server destroyed
Proto constraint validation failed (DecoderValidationError.Key: ["value length must be at least " '\x01' " bytes"]):

[derekargueta]

Can you give more information on what you're trying to accomplish, the configuration you were trying, and the HTTP request you made?