Getting JSON Logs into Honeycomb | Honeycomb

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Getting JSON Logs into Honeycomb

JSON is one of the most flexible formats in the data landscape we have today, and our JSON connector is perfect for your application’s custom log data.

Unstructured text logs are so 2009; whether you are primarily using Honeycomb, json over Logstash, or some other JSON-friendly service, pointing your existing logs at Honeycomb is simple.

Data Expectations 

Honeycomb expects data with a flat structure. By default, any structure deeper than top level keys will be serialized and a string representation of the content will be used in the field. However, Honeycomb can automatically unpack nested JSON objects and flatten them into unique columns. This is a per-dataset setting, and it is off by default. You must be a team owner to change this setting.

If you enable this setting, nested objects will be flattened with new fields and field names created based on the keys. For example, {"outer": {"inner": 42}} would become a field outer.inner with a value of 42.

To tell Honeycomb to automatically unpack JSON objects:

  1. Navigate to Settings > Schema for the dataset you want to configure.
  2. Check “Automatically unpack nested JSON”
  3. Choose the “Maximum unpacking depth” for your data.

Changing this setting takes effect within 60 seconds.

Note: If your objects are deeply-nested, unpacking may result in a very large number of columns in Honeycomb. Consider unpacking only to the level of columns you will find useful. Any objects nested more deeply than the depth you select here will be converted to strings under the last unpacked column. In particular, if nested structures in your data can be created/added by your users (for example, HTTP headers), consider not unpacking them to that level.


Download and install the latest honeytail by running:

# Download and install the AMD64 debian package
wget -q && \
echo '971ba06886c5436927a17f8494fe518084a385cb9b9b28e541296d658eb5cc8d  honeytail_1.8.1_amd64.deb' | sha256sum -c && \
sudo dpkg -i honeytail_1.8.1_amd64.deb

The packages install honeytail, its config file /etc/honeytail/honeytail.conf, and some start scripts. Build honeytail from source if you need it in an unpackaged form or for ad-hoc use.

You should modify the config file and uncomment and set:

  • ParserName to json
  • WriteKey to your API key, available from the account page
  • LogFiles to the path for the log file you want to ingest, or - for stdin
  • Dataset to the name of the dataset you wish to create with this log file.

Launch the Agent 

Start up a honeytail process using upstart or systemd or by launching the process by hand. This will tail the log file specified in the config and leave the process running as a daemon.

sudo initctl start honeytail

Backfilling Archived Logs 

To backfill existing data, run honeytail with --backfill the first time:

honeytail -c /etc/honeytail/honeytail.conf \
  --file /var/log/myapp/log12.json \

This command can also be used at any point to backfill from older, rotated log files. You can read more about our backfill behavior here.

Note: (If you have chosen to backfill from old JSON logs, do not forget to transition into the default streaming behavior to stream live logs to Honeycomb!)

Timestamp Parsing 

Honeycomb expects all events to contain a timestamp field; if one is not provided, the server will associate the current time of ingest with the given payload.

By default, we look for a few candidate fields based on name ("timestamp", "time") and handle the following time formats:

  • RFC3339 (2006-01-02T15:04:05Z07:00)
  • RFC3339 with nanoseconds (2006-01-02T15:04:05.999999999Z07:00)
  • Unix string representation (Mon Jan 2 15:04:05 MST 2006)
  • Ruby string representation (Mon Jan 02 15:04:05 -0700 2006)
  • Golang string representation (2006-01-02 15:04:05.999999999 -0700 MST)

If your timestamps are not correctly handled by the above formats, use the --json.timefield and --json.format flags to help honeytail understand where and how to extract the event’s timestamp.

For example, given a JSON log file with events like the following:

{"color":"orange","size":3,"server_time":"Aug 12 2016, 15:12:06 -0800"}
{"color":"blue","server_time":"Sep 01 2016, 06:10:32 -0800","size":4}

The command to consume those log lines (while retaining the "server_time" field as the event’s timestamp) would look something like:

honeytail --writekey=YOUR_API_KEY --dataset="API Server Logs" --parser=json \
  --file=/var/log/api_server.log \
  --json.timefield="server_time" --json.format="%b %d %Y, %k:%M:%S %z"

The --json.timefield="server_time" argument tells honeytail to consider the "server_time" value to be the canonical timestamp for the events in the specified file.

The --json.format argument specifies the timestamp format to be used while parsing. (It understands common strftime formats.)

Ultimately, the above command would would produce events with the fields (note the times below are represented in UTC; Honeycomb parses time zone information if provided).

time color size
2016-08-12T23:12:06Z orange 3
2016-09-01T14:10:32Z blue 4

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