stats: fix crash on invalid json

[timonwong]

Signed-off-by: Tianpeng Wang tpwang@alauda.io

What this PR does / why we need it:

When the stats plugin starts with wrong JSON config (ill-formatted for example), it will crash on any request (healthcheck for example) which makes pod crash repeatedly (or fail to start if healthcheck configured).

[istio-testing]

Hi @timonwong. Thanks for your PR.

I'm waiting for a istio member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[kyessenov]

/retest

[kyessenov]

LG.
What's the crash btw? We should probably make it not crash as well.

[timonwong]

@kyessenov The crash occurred when reporting metrics, when stats plugin is improperly configured, memberistio_dimensions_ for example won't get initialized.

The crash log looks like:

2022-04-07 2022-04-07T06:31:01.291495Z	info	Envoy proxy is ready
2022-04-07 2022-04-07T06:31:14.644469Z	critical	envoy backtrace	Caught Segmentation fault, suspect faulting address 0xf0
2022-04-07 2022-04-07T06:31:14.644560Z	critical	envoy backtrace	Backtrace (use tools/stack_decode.py to get line numbers):
2022-04-07 2022-04-07T06:31:14.644579Z	critical	envoy backtrace	Envoy version: 119f44fab6a17471c7e9acec311af5fb1fd6f70b/1.20.1/Modified/RELEASE/BoringSSL
2022-04-07 2022-04-07T06:31:14.644994Z	critical	envoy backtrace	#0: __restore_rt [0x7ff171b7b980]
2022-04-07 2022-04-07T06:31:14.814022Z	critical	envoy backtrace	#1: proxy_wasm::null_plugin::Stats::PluginRootContext::report() [0x55eac23d0831]
2022-04-07 2022-04-07T06:31:14.915397Z	critical	envoy backtrace	#2: proxy_wasm::null_plugin::Stats::PluginContext::onLog() [0x55eac23d3cf7]
2022-04-07 2022-04-07T06:31:15.018993Z	critical	envoy backtrace	#3: std::__1::__function::__func<>::operator()() [0x55eac2b6961b]
2022-04-07 2022-04-07T06:31:15.211963Z	critical	envoy backtrace	#4: proxy_wasm::ContextBase::onLog() [0x55eac2b74225]
2022-04-07 2022-04-07T06:31:15.316562Z	critical	envoy backtrace	#5: Envoy::Extensions::Common::Wasm::Context::log() [0x55eac2976cbc]
2022-04-07 2022-04-07T06:31:15.510410Z	critical	envoy backtrace	#6: Envoy::Http::FilterManager::log() [0x55eac41916dd]
2022-04-07 2022-04-07T06:31:15.613836Z	critical	envoy backtrace	#7: Envoy::Http::ConnectionManagerImpl::doDeferredStreamDestroy() [0x55eac4191347]
2022-04-07 2022-04-07T06:31:15.715907Z	critical	envoy backtrace	#8: Envoy::Http::ConnectionManagerImpl::doEndStream() [0x55eac4190e32]
2022-04-07 2022-04-07T06:31:15.819930Z	critical	envoy backtrace	#9: Envoy::Http::FilterManager::encodeData() [0x55eac41ab88e]
2022-04-07 2022-04-07T06:31:16.014518Z	critical	envoy backtrace	#10: Envoy::Router::UpstreamRequest::decodeData() [0x55eac4272771]
2022-04-07 2022-04-07T06:31:16.117170Z	critical	envoy backtrace	#11: Envoy::Http::ResponseDecoderWrapper::decodeData() [0x55eac40567cb]
2022-04-07 2022-04-07T06:31:16.117216Z	critical	envoy backtrace	#12: Envoy::Http::ResponseDecoderWrapper::decodeData() [0x55eac40567cb]
2022-04-07 2022-04-07T06:31:16.218930Z	critical	envoy backtrace	#13: Envoy::Http::Http1::ClientConnectionImpl::onMessageCompleteBase() [0x55eac41dde8b]
2022-04-07 2022-04-07T06:31:16.412339Z	critical	envoy backtrace	#14: Envoy::Http::Http1::ConnectionImpl::onMessageComplete() [0x55eac41d970d]
2022-04-07 2022-04-07T06:31:16.525208Z	critical	envoy backtrace	#15: Envoy::Http::Http1::LegacyHttpParserImpl::Impl::Impl()::{lambda()#3}::__invoke() [0x55eac41e1fbf]
2022-04-07 2022-04-07T06:31:16.710743Z	critical	envoy backtrace	#16: http_parser_execute [0x55eac452cfa9]
2022-04-07 2022-04-07T06:31:16.813024Z	critical	envoy backtrace	#17: Envoy::Http::Http1::LegacyHttpParserImpl::execute() [0x55eac41e19df]
2022-04-07 2022-04-07T06:31:16.914034Z	critical	envoy backtrace	#18: Envoy::Http::Http1::ConnectionImpl::dispatchSlice() [0x55eac41d7ad4]
2022-04-07 2022-04-07T06:31:17.017890Z	critical	envoy backtrace	#19: Envoy::Http::Http1::ConnectionImpl::dispatch() [0x55eac41d726c]
2022-04-07 2022-04-07T06:31:17.209562Z	critical	envoy backtrace	#20: Envoy::Http::Http1::ClientConnectionImpl::dispatch() [0x55eac41d6dbd]
2022-04-07 2022-04-07T06:31:17.311100Z	critical	envoy backtrace	#21: Envoy::Http::CodecClient::onData() [0x55eac40c3030]
2022-04-07 2022-04-07T06:31:17.415407Z	critical	envoy backtrace	#22: Envoy::Http::CodecClient::CodecReadFilter::onData() [0x55eac40c41b5]
2022-04-07 2022-04-07T06:31:17.515742Z	critical	envoy backtrace	#23: Envoy::Network::FilterManagerImpl::onContinueReading() [0x55eac444463f]
2022-04-07 2022-04-07T06:31:17.617222Z	critical	envoy backtrace	#24: Envoy::Network::ConnectionImpl::onReadReady() [0x55eac443dd06]
2022-04-07 2022-04-07T06:31:17.717499Z	critical	envoy backtrace	#25: Envoy::Network::ConnectionImpl::onFileEvent() [0x55eac443b74f]
2022-04-07 2022-04-07T06:31:17.909517Z	critical	envoy backtrace	#26: std::__1::__function::__func<>::operator()() [0x55eac44218b1]
2022-04-07 2022-04-07T06:31:18.013169Z	critical	envoy backtrace	#27: Envoy::Event::FileEventImpl::assignEvents()::$_1::__invoke() [0x55eac4422dbc]
2022-04-07 2022-04-07T06:31:18.114961Z	critical	envoy backtrace	#28: event_process_active_single_queue [0x55eac454c8e0]
2022-04-07 2022-04-07T06:31:18.317056Z	critical	envoy backtrace	#29: event_base_loop [0x55eac454b2f1]
2022-04-07 2022-04-07T06:31:18.416357Z	critical	envoy backtrace	#30: Envoy::Server::WorkerImpl::threadRoutine() [0x55eac3e37cbd]
2022-04-07 2022-04-07T06:31:18.521674Z	critical	envoy backtrace	#31: Envoy::Thread::ThreadImplPosix::ThreadImplPosix()::{lambda()#1}::__invoke() [0x55eac4780783]
2022-04-07 2022-04-07T06:31:18.521758Z	critical	envoy backtrace	#32: start_thread [0x7ff171b706db]