There are a few things to note about what Fn logs.
We recommend using logspout to forward your logs to a log aggregator of your choice.
All logs are emitted in logfmt format for easy parsing.
Every function call/request is assigned a call_id. If you search your logs, you can track all the activity
for each function call and find errors on a call by call basis. For example, these are the log lines for an aynschronous
function call:
Note the easily searchable call_id=x format.
call_id=477949e2-922c-5da9-8633-0b2887b79f6eYou may add a syslog url to any function application and all functions that
exist under that application will ship all of their logs to it. You may
provide a comma separated list, if desired. Currently, we support tcp,
udp, and tls, and this will not work if behind a proxy [yet?] (this is my
life now). This feature only works for 'hot' functions.
An example syslog url is:
tls://logs.papertrailapp.com:1
We log in a syslog format, with some variables added in logfmt format. If you find logfmt format offensive, please open an issue and we will consider adding more formats (or open a PR that does it, with tests, and you will receive 1 free cookie along with the feature you want). The logs from the functions themselves are not formatted, only our pre-amble, thus, if you'd like a fully logfmt line, you must use a logfmt logger to log from your function.
- All log lines are sent as level error w/ the current time and
fnas hostname. - call_id, func_name, and app_id will prefix every log line.
<11>2 1982-06-25T12:00:00Z fn - - - - call_id=12345 func_name=yo/yo app_id=54321 this is your log line