You will need to tell syslog-ng to encode this value as an integer.
pair("datetime" int64("${S_UNIXTIME}${S_MSEC}"))
Please note the int64 type hint

I tried it and it also didn't work.

I figured out the solution by using the datetime function, apparently when working with MongoDB time-series or TTL, it is mandatory that the datetime pair value must be sent of type datetime not a string, int or other types otherwise MongoDB won't accept it. Here is the pair structure worked for me:

pair("createdAt" datetime($S_UNIXTIME))

Thanks.

On Sun, 6 Aug 2023 at 21:51, Ibrahim Al Mahfooz <ibrahim.nezar@sevennet.net> wrote:

Hello Evan,

Thanks for your response,
If you change your datetime to be compsed of the epoc and the 
milliseconds it should work.

pair("datetime" "${S_UNIXTIME}${S_MSEC}")
I made the change but didn't work, got same log error, also you can see the datetime is UNIX+MSEC is reflected in the datetime pair but
[2023-08-06T21:38:53.717614] Outgoing message to MongoDB destination; message='datetime=1691347133717 host=10.36.0.6 portaction=initial portstatus=assigned privateip=10.34.102.175 publicip=98.75.22.22 publicportrange=9048~10047 ', driver='d_mongodb_ttl#0'
[2023-08-06T21:38:53.718564] Failed to insert into MongoDB; time_reopen='10', reason='\'datetime\' must be present and contain a valid BSON UTC datetime value', driver='d_mongodb_ttl#0'

From what I understand from MongoDB, BSON format is mandatory, and MongoDB expectation is this binary format only, if syslog-ng is not capable of sending such format, most probably things will not work out.

Do you have a working MongoDB Time-Series setup with syslog-ng before?

Best regards
On Sun, 6 Aug 2023 at 18:04, Ibrahim Al Mahfooz <ibrahim.nezar@sevennet.net> wrote:
Hello,

I have integration working fine between syslog-ng v3.38 and MongoDB v6. I am working to enable MongoDB Time-Series Collections on a testing DB for the purpose of having better efficiency and improved queries over time.

I created the DB and collection, tested it by Mongo Compass client, then I tried to send the data from syslog-ng but it didn't work. MongoDB is throwing the following error:
"17:12:57. 483 | [2023-08-06T17:12:57.355549] Failed to insert into MongoDB; time_reopen='10', reason='\'datetime\' must be present and contain a valid BSON UTC datetime value', driver='d_mongodb_ttl#0"

My understanding is that it is a must to send the time/date to MongoDB with Time Series enabled DB a BSON format Date. Any suggestions?

Below is the mongoDB destination config:

destination d_mongodb_ttl {
mongodb(
uri("mongodb://192.168.1.19:27017/syslog-ng_ttl")
collection("logs")
value-pairs(
scope("selected-macros")
exclude("SOURCEIP")
exclude("TAGS")
pair("datetime" "${S_ISODATE}")
pair("privateip" "${privateip}")
pair("publicip" "${publicip}")
pair("publicportrange" "${publicportrange}")
pair("portaction" "${AI}")
pair("portstatus" "${AL}")
pair("host" "${HOST}"))
);
};

Appreciate your help

Ibrahim Abdulatif