chore: update helio and improve our stack overflow resiliency (#4349)

1. Run CI/Regression tests with HELIO_STACK_CHECK=4096.
   This will crash if a fiber stack usage goes below this limit.
2. Increase shard queue stack size to 64KB
3. Increase fiber stack size to 40KB on Debug builds.
4. Updated helio has some changes around the TLS socket code.
   In addition we add a helper script to generate self-signed certificates helpful for local development work.

Signed-off-by: Roman Gershman <roman@dragonflydb.io>

Author: romange

.github/workflows/ci.yml

@@ -111,6 +111,7 @@ jobs:
             -DCMAKE_CXX_COMPILER="${{matrix.compiler.cxx}}" \
             -DCMAKE_CXX_COMPILER_LAUNCHER=sccache -DCMAKE_C_COMPILER_LAUNCHER=sccache \
             -DCMAKE_CXX_FLAGS="${{matrix.cxx_flags}} -no-pie" -DWITH_AWS:BOOL=OFF \
+            -DHELIO_STACK_CHECK:STRING=4096 \
             -L
           cd ${GITHUB_WORKSPACE}/build && pwd
           du -hcs _deps/

.github/workflows/regression-tests.yml

@@ -36,7 +36,7 @@ jobs:
           # -no-pie to disable address randomization so we could symbolize stacktraces
           cmake -B ${GITHUB_WORKSPACE}/build -DCMAKE_BUILD_TYPE=${{matrix.build-type}} -GNinja \
                 -DCMAKE_CXX_COMPILER_LAUNCHER=ccache -DPRINT_STACKTRACES_ON_SIGNAL=ON \
-                -DCMAKE_CXX_FLAGS=-no-pie
+                -DCMAKE_CXX_FLAGS=-no-pie -DHELIO_STACK_CHECK:STRING=4096
 
           cd ${GITHUB_WORKSPACE}/build  && ninja dragonfly
           pwd

helio

@@ -685,7 +685,7 @@ void Connection::HandleRequests() {
       FiberSocketBase::AcceptResult aresult = socket_->Accept();
 
       if (!aresult) {
-        LOG(WARNING) << "Error handshaking " << aresult.error().message();
+        LOG(INFO) << "Error handshaking " << aresult.error().message();
         return;
       }
       VLOG(1) << "TLS handshake succeeded";

src/facade/dragonfly_connection.cc

@@ -96,7 +96,12 @@ namespace {
 // Default stack size for fibers. We decrease it by 16 bytes because some allocators
 // need additional 8-16 bytes for their internal structures, thus over reserving additional
 // memory pages if using round sizes.
+#ifdef NDEBUG
 constexpr size_t kFiberDefaultStackSize = 32_KB - 16;
+#else
+// Increase stack size for debug builds.
+constexpr size_t kFiberDefaultStackSize = 40_KB - 16;
+#endif
 
 using util::http::TlsClient;
 

src/server/dfly_main.cc

@@ -4,7 +4,6 @@
 
 #include "server/snapshot.h"
 
-#include <absl/functional/bind_front.h>
 #include <absl/strings/match.h>
 #include <absl/strings/str_cat.h>
 
@@ -64,13 +63,18 @@ bool SliceSnapshot::IsSnaphotInProgress() {
 void SliceSnapshot::Start(bool stream_journal, SnapshotFlush allow_flush) {
   DCHECK(!snapshot_fb_.IsJoinable());
 
-  auto db_cb = absl::bind_front(&SliceSnapshot::OnDbChange, this);
+  auto db_cb = [this](DbIndex db_index, const DbSlice::ChangeReq& req) {
+    OnDbChange(db_index, req);
+  };
+
   snapshot_version_ = db_slice_->RegisterOnChange(std::move(db_cb));
 
   if (stream_journal) {
     auto* journal = db_slice_->shard_owner()->journal();
     DCHECK(journal);
-    auto journal_cb = absl::bind_front(&SliceSnapshot::OnJournalEntry, this);
+    auto journal_cb = [this](const journal::JournalItem& item, bool await) {
+      OnJournalEntry(item, await);
+    };
     journal_cb_id_ = journal->RegisterOnChange(std::move(journal_cb));
   }
 
@@ -168,7 +172,7 @@ void SliceSnapshot::IterateBucketsFb(bool send_full_sync_cut) {
       }
 
       PrimeTable::Cursor next =
-          pt->TraverseBuckets(cursor, absl::bind_front(&SliceSnapshot::BucketSaveCb, this));
+          pt->TraverseBuckets(cursor, [this](auto it) { return BucketSaveCb(it); });
       cursor = next;
       PushSerialized(false);
 
@@ -229,7 +233,9 @@ void SliceSnapshot::SwitchIncrementalFb(LSN lsn) {
       FiberAtomicGuard fg;
       serializer_->SendFullSyncCut();
     }
-    auto journal_cb = absl::bind_front(&SliceSnapshot::OnJournalEntry, this);
+    auto journal_cb = [this](const journal::JournalItem& item, bool await) {
+      OnJournalEntry(item, await);
+    };
     journal_cb_id_ = journal->RegisterOnChange(std::move(journal_cb));
     PushSerialized(true);
   } else {

src/server/snapshot.cc

@@ -667,7 +667,6 @@ void Transaction::RunCallback(EngineShard* shard) {
   DCHECK_EQ(shard, EngineShard::tlocal());
 
   RunnableResult result;
-  auto& db_slice = GetDbSlice(shard->shard_id());
   try {
     result = (*cb_ptr_)(this, shard);
 
@@ -691,6 +690,7 @@ void Transaction::RunCallback(EngineShard* shard) {
     LOG(FATAL) << "Unexpected exception " << e.what();
   }
 
+  auto& db_slice = GetDbSlice(shard->shard_id());
   db_slice.OnCbFinish();
 
   // Handle result flags to alter behaviour.

src/server/transaction.cc

@@ -0,0 +1,87 @@
+#!/bin/bash
+set -e
+
+SCRIPT_DIR=$(dirname "$0")
+ROOT_DIR=$(readlink -f "$SCRIPT_DIR/../..")
+GEN_DIR=$ROOT_DIR/genfiles/tls
+
+
+#   genfiles/tls/ca.{crt,key}          Self signed CA certificate.
+#   genfiles/tls/dragonfly.{crt,key}   A certificate with no key usage/policy restrictions.
+#   genfiles/tls/client.{crt,key}      A certificate restricted for SSL client usage.
+#   genfiles/tls/server.{crt,key}      A certificate restricted for SSL server usage.
+
+: '
+To run dragonfly use:
+dragonfly --tls --tls_key_file ../genfiles/tls/server.key  --tls_cert_file ../genfiles/tls/server.crt -requirepass pass
+
+Or with CA (does not require password):
+dragonfly --tls --tls_key_file ../genfiles/tls/server.key  --tls_cert_file ../genfiles/tls/server.crt \
+--tls_ca_cert_file ../genfiles/tls/ca.crt
+
+To connect with client (without ca):
+openssl s_client   -state -crlf  -connect 127.0.0.1:6379
+
+With CA:
+openssl s_client   -state -crlf -CAfile ../genfiles/tls/ca.crt  -cert ../genfiles/tls/client.crt -key ../genfiles/tls/client.key  -connect 127.0.0.1:6379
+
+Similarly, to connect with redis-cli (no CA):
+redis-cli --tls --insecure -a pass
+
+With CA:
+redis-cli --tls  --cacert ../genfiles/tls/ca.crt  --cert ../genfiles/tls/client.crt --key ../genfiles/tls/client.key
+
+memtier (without CA):
+memtier_benchmark --tls --key ../genfiles/tls/client.key  --cert ../genfiles/tls/client.crt -a pass
+
+memtier (with CA):
+memtier_benchmark --tls --key ../genfiles/tls/client.key  --cert ../genfiles/tls/client.crt --cacert ../genfiles/tls/ca.crt
+'
+
+generate_cert() {
+    local name=$1
+    local cn="$2"
+    local opts="$3"
+
+    local keyfile=$GEN_DIR/${name}.key
+    local certfile=$GEN_DIR/${name}.crt
+
+    [ -f $keyfile ] || openssl genpkey -algorithm ED25519 -out $keyfile
+    openssl req -new -sha256 \
+        -subj "/O=Dragonfly Test/CN=$cn" \
+        -key $keyfile | \
+        openssl x509 \
+            -req -sha256 \
+            -CA $GEN_DIR/ca.crt \
+            -CAkey $GEN_DIR/ca.key \
+            -CAserial $GEN_DIR/ca.txt \
+            -CAcreateserial \
+            -days 365 \
+            $opts \
+            -out $certfile
+}
+
+mkdir -p $GEN_DIR
+[ -f $GEN_DIR/ca.key ] || openssl genpkey -algorithm ED25519 -out $GEN_DIR/ca.key
+
+# -x509: self-signed certificate, -nodes: no password
+openssl req \
+    -x509 -new -nodes -sha256 \
+    -key $GEN_DIR/ca.key \
+    -days 3650 \
+    -subj '/O=Dragonfly Test/CN=Certificate Authority' \
+    -out $GEN_DIR/ca.crt
+
+cat > $GEN_DIR/openssl.cnf <<_END_
+[ server_cert ]
+keyUsage = digitalSignature, keyEncipherment
+nsCertType = server
+
+[ client_cert ]
+keyUsage = digitalSignature, keyEncipherment
+nsCertType = client
+_END_
+
+generate_cert server "Server-only" "-extfile $GEN_DIR/openssl.cnf -extensions server_cert"
+generate_cert client "Client-only" "-extfile $GEN_DIR/openssl.cnf -extensions client_cert"
+generate_cert dragonfly "Generic-cert"