tests: add reconnect test

tests/CMakeLists.txt

@@ -143,6 +143,8 @@ add_executable(clusterclient_all_nodes clusterclient_all_nodes.c)
 target_link_libraries(clusterclient_all_nodes hiredis_cluster hiredis ${SSL_LIBRARY})
 add_executable(clusterclient_async clusterclient_async.c)
 target_link_libraries(clusterclient_async hiredis_cluster hiredis ${SSL_LIBRARY} ${LIBEVENT_LIBRARY})
+add_executable(clusterclient_reconnect_async clusterclient_reconnect_async.c)
+target_link_libraries(clusterclient_reconnect_async hiredis_cluster hiredis ${SSL_LIBRARY} ${LIBEVENT_LIBRARY})
 add_test(NAME set-get-test
          COMMAND "${CMAKE_SOURCE_DIR}/tests/scripts/set-get-test.sh"
                  "$<TARGET_FILE:clusterclient>"
@@ -173,3 +175,7 @@ add_test(NAME dbsize-to-all-nodes-test
          COMMAND "${CMAKE_SOURCE_DIR}/tests/scripts/dbsize-to-all-nodes-test.sh"
                  "$<TARGET_FILE:clusterclient_all_nodes>"
                  WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}/tests/scripts/")
+add_test(NAME reconnect-test
+         COMMAND "${CMAKE_SOURCE_DIR}/tests/scripts/reconnect-test.sh"
+                "$<TARGET_FILE:clusterclient_reconnect_async>"
+                WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}/tests/scripts/")

tests/clusterclient_reconnect_async.c

@@ -0,0 +1,111 @@
+/*
+ * This program connects to a Redis node and then reads commands from stdin, such
+ * as "SET foo bar", one per line and prints the results to stdout.
+ *
+ * The behaviour is similar to that of clusterclient_async.c, but it sends the
+ * next command after receiving a reply from the previous command. It also works
+ * for standalone Redis nodes (without cluster mode), and uses the
+ * redisClusterAsyncCommandToNode function to send the command to the first node.
+ * If it receives any I/O error, the program performs a reconnect.
+ */
+
+#include "adapters/libevent.h"
+#include "hircluster.h"
+#include "test_utils.h"
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+/* Unfortunately there is no error code for this error to match */
+#define REDIS_ENOCLUSTER "ERR This instance has cluster support disabled"
+
+void sendNextCommand(int, short, void *);
+
+void connectToRedis(redisClusterAsyncContext *acc) {
+    /* reset Redis context in case of reconnect */
+    redisClusterAsyncDisconnect(acc);
+
+    int status = redisClusterConnect2(acc->cc);
+    if (status == REDIS_OK) {
+        // cluster mode
+    } else if (acc->cc->err && strcmp(acc->cc->errstr, REDIS_ENOCLUSTER) == 0) {
+        printf("[no cluster]\n");
+        acc->cc->err = 0;
+        memset(acc->cc->errstr, '\0', strlen(acc->cc->errstr));
+    } else {
+        printf("Connect error: %s\n", acc->cc->errstr);
+        exit(-1);
+    }
+}
+
+void replyCallback(redisClusterAsyncContext *acc, void *r, void *privdata) {
+    UNUSED(privdata);
+    redisReply *reply = (redisReply *)r;
+
+    if (reply == NULL &&
+        (acc->err == REDIS_ERR_IO || acc->err == REDIS_ERR_EOF)) {
+        printf("[reconnect]\n");
+        connectToRedis(acc);
+    } else {
+        printf("%s\n", reply->str);
+    }
+
+    // schedule reading from stdin and sending next command
+    event_base_once(acc->adapter, -1, EV_TIMEOUT, sendNextCommand, acc, NULL);
+}
+
+void sendNextCommand(int fd, short kind, void *arg) {
+    UNUSED(fd);
+    UNUSED(kind);
+    redisClusterAsyncContext *acc = arg;
+
+    char command[256];
+    if (fgets(command, 256, stdin)) {
+        size_t len = strlen(command);
+        if (command[len - 1] == '\n') // Chop trailing line break
+            command[len - 1] = '\0';
+
+        dictIterator di;
+        dictInitIterator(&di, acc->cc->nodes);
+
+        dictEntry *de = dictNext(&di);
+        assert(de);
+        cluster_node *node = dictGetEntryVal(de);
+        assert(node);
+
+        int status = redisClusterAsyncCommandToNode(acc, node, replyCallback,
+                                                    NULL, command);
+        ASSERT_MSG(status == REDIS_OK, acc->errstr);
+    } else {
+        // disconnect if nothing is left to read from stdin
+        redisClusterAsyncDisconnect(acc);
+    }
+}
+
+int main(int argc, char **argv) {
+    if (argc <= 1) {
+        fprintf(stderr, "Usage: %s HOST:PORT\n", argv[0]);
+        exit(1);
+    }
+    const char *initnode = argv[1];
+
+    redisClusterAsyncContext *acc = redisClusterAsyncContextInit();
+    assert(acc);
+    redisClusterSetOptionAddNodes(acc->cc, initnode);
+    redisClusterSetOptionRouteUseSlots(acc->cc);
+
+    struct event_base *base = event_base_new();
+    int status = redisClusterLibeventAttach(acc, base);
+    assert(status == REDIS_OK);
+
+    connectToRedis(acc);
+    // schedule reading from stdin and sending next command
+    event_base_once(acc->adapter, -1, EV_TIMEOUT, sendNextCommand, acc, NULL);
+
+    event_base_dispatch(base);
+
+    redisClusterAsyncFree(acc);
+    event_base_free(base);
+    return 0;
+}

tests/scripts/reconnect-test.sh

@@ -0,0 +1,64 @@
+#!/bin/sh
+
+# Usage: $0 /path/to/clusterclient-binary
+
+clientprog=${1:-./clusterclient_reconnect_async}
+testname=reconnect-test
+
+# Sync process just waiting for server to be ready to accept connection.
+perl -we 'use sigtrap "handler", sub{exit}, "CONT"; sleep 1; die "timeout"' &
+syncpid=$!
+
+# Start simulated server
+timeout 5s ./simulated-redis.pl -p 7400 -d --sigcont $syncpid <<'EOF' &
+EXPECT CONNECT
+EXPECT ["CLUSTER", "SLOTS"]
+SEND -ERR This instance has cluster support disabled
+EXPECT CLOSE
+EXPECT CONNECT
+EXPECT ["SET", "foo", "bar"]
+SEND +OK
+EXPECT ["GET", "foo"]
+SEND "bar"
+CLOSE
+EXPECT CONNECT
+EXPECT ["CLUSTER", "SLOTS"]
+SEND -ERR This instance has cluster support disabled
+EXPECT CLOSE
+EXPECT CONNECT
+EXPECT ["GET", "foo"]
+SEND "bar"
+EXPECT CLOSE
+EOF
+server=$!
+
+# Wait until server is ready to accept client connection
+wait $syncpid;
+
+# Run client
+timeout 3s "$clientprog" 127.0.0.1:7400 > "$testname.out" <<'EOF'
+SET foo bar
+GET foo
+GET foo
+GET foo
+EOF
+clientexit=$?
+
+# Wait for server to exit
+wait $server; serverexit=$?
+
+# Check exit statuses
+if [ $serverexit -ne 0 ]; then
+    echo "Simulated server exited with status $serverexit"
+    exit $serverexit
+fi
+if [ $clientexit -ne 0 ]; then
+    echo "$clientprog exited with status $clientexit"
+    exit $clientexit
+fi
+
+# Check the output from clusterclient
+printf '[no cluster]\nOK\nbar\n[reconnect]\n[no cluster]\nbar\n' | cmp "$testname.out" - || exit 99
+
+# Clean up
+rm "$testname.out"