1 files changed, 67 insertions, 0 deletions
diff --git a/jstests/libs/check_log.js b/jstests/libs/check_log.js
new file mode 100644
index 00000000000..81bab58ce2a
--- /dev/null
+++ b/jstests/libs/check_log.js
@@ -0,0 +1,67 @@
+/*
+ * Helper functions which connect to a server, and check its logs for particular strings.
+ */
+var checkLog;
+
+(function() {
+    "use strict";
+
+    if (checkLog) {
+        return;  // Protect against this file being double-loaded.
+    }
+
+    checkLog = (function() {
+        /*
+         * Calls the 'getLog' function at regular intervals on the provided connection 'conn' until
+         * the provided 'msg' is found in the logs, or 5 minutes have elapsed. Throws an exception
+         * on timeout.
+         */
+        var contains = function(conn, msg) {
+            assert.soon(
+                function() {
+                    var logMessages =
+                        assert.commandWorked(conn.adminCommand({getLog: 'global'})).log;
+                    for (var i = 0; i < logMessages.length; i++) {
+                        if (logMessages[i].indexOf(msg) != -1) {
+                            return true;
+                        }
+                    }
+                    return false;
+                },
+                'Could not find log entries containing the following message: ' + msg,
+                5 * 60 * 1000,
+                300);
+        };
+
+        /*
+         * Calls the 'getLog' function at regular intervals on the provided connection 'conn' until
+         * the provided 'msg' is found in the logs exactly 'expectedCount' times, or 5 minutes have
+         * elapsed.
+         * Throws an exception on timeout.
+         */
+        var containsWithCount = function(conn, msg, expectedCount) {
+            var count = 0;
+            assert.soon(
+                function() {
+                    var logMessages =
+                        assert.commandWorked(conn.adminCommand({getLog: 'global'})).log;
+                    for (var i = 0; i < logMessages.length; i++) {
+                        if (logMessages[i].indexOf(msg) != -1) {
+                            count++;
+                        }
+                    }
+
+                    return expectedCount === count;
+                },
+                'Expected ' + expectedCount + ', but instead saw ' + count +
+                    ' log entries containing the following message: ' + msg,
+                5 * 60 * 1000,
+                300);
+        };
+
+        return {
+            contains: contains,
+            containsWithCount: containsWithCount
+        };
+    })();
+})();