Request to Kubernetes Pod from PHP GRPC client (from Docker) - php

Question

everyone!
The situation is like this:
I have a pod in kubernetes, I forward a port to it like this -
kubectl port-forward deploy/reporter-dev 8585:8081 --address 0.0.0.0.0
I connect from Postman to my local address 192.168.31.205:8585 - the server from kubernetes responds correctly.
But as soon as I try to connect from PHP application from Docker nothing works.
This is connection code from PHP: (php classes generated from PROTO before)
class GroupService
{
private ReportGroupsClient|BaseStub|null $reportGroupsClient;
public function __construct()
{
$this->reportGroupsClient = Yii::$container->get(
ReportGroupsClient::class,
['192.168.31.205:8585', [
'credentials' => ChannelCredentials::createInsecure(),
]]
);
}
public function getReportGroupsList()
{
$res = $this->reportGroupsClient->GetList(new ReportGroupsGetListRequest([
'limit' => 10,
'offset' => 0,
]))->wait();
//exec('/var/www/grpcurl -insecure 192.168.31.205:8585 retail.reporter.ReportGroups/GetList', $res);
return $res;
}
}
public function actionHealth(): void
{
$this->log("Start DEBUG gRPC");
$rr = new GroupService();
$res = $rr->getReportGroupsList();
var_dump($res);
$this->log("End of debug");
}
that return the error:
/var/www # GRPC_VERBOSITY=debug GPRC_TRACE=all php yii reports/report/health
I0210 07:22:57.540640544 357 ev_epoll1_linux.cc:121] grpc epoll fd: 4
D0210 07:22:57.540835960 357 ev_posix.cc:171] Using polling engine: epoll1
D0210 07:22:57.541246752 357 lb_policy_registry.cc:42] registering LB policy factory for "grpclb"
D0210 07:22:57.541344669 357 lb_policy_registry.cc:42] registering LB policy factory for "rls_experimental"
D0210 07:22:57.541406252 357 lb_policy_registry.cc:42] registering LB policy factory for "priority_experimental"
D0210 07:22:57.541479794 357 lb_policy_registry.cc:42] registering LB policy factory for "weighted_target_experimental"
D0210 07:22:57.541527044 357 lb_policy_registry.cc:42] registering LB policy factory for "pick_first"
D0210 07:22:57.541548752 357 lb_policy_registry.cc:42] registering LB policy factory for "round_robin"
D0210 07:22:57.541621877 357 lb_policy_registry.cc:42] registering LB policy factory for "ring_hash_experimental"
D0210 07:22:57.541887044 357 certificate_provider_registry.cc:33] registering certificate provider factory for "file_watcher"
D0210 07:22:57.541919794 357 lb_policy_registry.cc:42] registering LB policy factory for "cds_experimental"
D0210 07:22:57.541977919 357 lb_policy_registry.cc:42] registering LB policy factory for "xds_cluster_impl_experimental"
D0210 07:22:57.542039169 357 lb_policy_registry.cc:42] registering LB policy factory for "xds_cluster_resolver_experimental"
D0210 07:22:57.542087877 357 lb_policy_registry.cc:42] registering LB policy factory for "xds_cluster_manager_experimental"
2023-02-10 07:22:57 Start DEBUG gRPC
D0210 07:22:57.649119960 357 dns_resolver.cc:162] Using native dns resolver
I0210 07:22:57.652611710 359 socket_utils_common_posix.cc:429] Disabling AF_INET6 sockets because ::1 is not available.
I0210 07:22:58.759204128 357 subchannel.cc:948] subchannel 0xffff81952db0 {address=ipv4:192.168.31.205:8585, args=grpc.client_channel_factory=0xffff8195d050, grpc.default_authority=192.168.31.205:8585, grpc.internal.channel_credentials=0xffff81916b90, grpc.internal.security_connector=0xffff8191be30, grpc.internal.subchannel_pool=0xffff8191a740, grpc.resource_quota=0xffff8191c420, grpc.server_uri=dns:///192.168.31.205:8585}: connect failed: {"created":"#1676013778.758779961","description":"Endpoint read failed","file":"/tmp/pear/temp/grpc/src/core/ext/transport/chttp2/transport/chttp2_transport.cc","file_line":2572,"occurred_during_write":0,"referenced_errors":[{"created":"#1676013778.758739461","description":"Socket closed","fd":6,"file":"/tmp/pear/temp/grpc/src/core/lib/iomgr/tcp_posix.cc","file_line":802,"grpc_status":14,"target_address":"ipv4:192.168.31.205:8585"}]}
I0210 07:22:58.759450044 357 subchannel.cc:888] subchannel 0xffff81952db0 {address=ipv4:192.168.31.205:8585, args=grpc.client_channel_factory=0xffff8195d050, grpc.default_authority=192.168.31.205:8585, grpc.internal.channel_credentials=0xffff81916b90, grpc.internal.security_connector=0xffff8191be30, grpc.internal.subchannel_pool=0xffff8191a740, grpc.resource_quota=0xffff8191c420, grpc.server_uri=dns:///192.168.31.205:8585}: Retry immediately
I0210 07:22:58.759495461 357 subchannel.cc:914] subchannel 0xffff81952db0 {address=ipv4:192.168.31.205:8585, args=grpc.client_channel_factory=0xffff8195d050, grpc.default_authority=192.168.31.205:8585, grpc.internal.channel_credentials=0xffff81916b90, grpc.internal.security_connector=0xffff8191be30, grpc.internal.subchannel_pool=0xffff8191a740, grpc.resource_quota=0xffff8191c420, grpc.server_uri=dns:///192.168.31.205:8585}: failed to connect to channel, retrying
array(2) {
[0]=>
NULL
[1]=>
object(stdClass)#241 (3) {
["metadata"]=>
array(0) {
}
["code"]=>
int(14)
["details"]=>
string(34) "failed to connect to all addresses"
}
}
2023-02-10 07:22:58 End of debug
If I uncomment "exec" function - grpcurl answer correctly!
From this I conclude that the request from the Docker container works fine, but the GRPC client specifically does not work for some reason. What can it be?

Answer 1

The error message Disabling AF_INET6 sockets because ::1 is not available says that it tried to use IPv6 and failed, so it's using IPv4 instead. That message has been silenced in the most recent release of the gRPC package. Check your gRPC version, if required update to the recent version. Refer to the similar SO for more information.
DNS resolution failure with gRPC: Looks like you're using a workaround to run your binary under environment variable setting: GRPC_DNS_RESOLVER=native, still you're getting the below error:
`connect failed: {"created":"#1676013778.758779961","description":"Endpoint read failed","file":"/tmp/pear/temp/grpc/src/core/ext/transport/chttp2/transport/chttp2_transport.cc","file_line":2572,"occurred_during_write":0,"referenced_errors":[{"created":"#1676013778.758739461","description":"Socket closed","fd":6,"file":"/tmp/pear/temp/grpc/src/core/lib/iomgr/tcp_posix.cc","file_line":802,"grpc_status":14,"target_address":"ipv4:192.168.31.205:8585"}]`}
See github issue on Endpoint read failed in client request #144 which may help to resolve your issue.