The data stored in Humio is called events. An event is a piece of data and an associated timestamp.
Examples of events include:
but ANY piece of data with an associated timestamp can be thought of as an event.
When data is sent to Humio - in this example a log line - the associated parser converts the data into an event. If Humio received:
[2018-10-11 22:00:10] INFO - User Logged In. userId=97110
This might be turned into an event data containing the following fields:
|@rawstring||[2018-10-11 22:00:10] INFO - User Logged In. userId=97110|
|message||User Logged In.|
There are three types of fields:
Each even has some metadata attached to it on ingestion, e.g. all events will
Notice that metadata fields start with all
@ to make them easy to identity.
The three most important are
@display and will be
described in detail below.
Tags fields that define how events are physical stored and indexed. They are used for speeding up queries.
Users can associate custom tags as part of the parsing and ingestion process.
But their use is usually very limited. The only built-in tags are
both are described in detail below.
Usually the client sending data to Humio will be configured to include
#source tags, containing the hostname and file the event was read from.
Any field that is not a tag or metadata is a user field. They are extracted at ingest by a parser or at query time by a regular expression. User fields are usually the interesting part of an event, containing application specific information.
Humio represents the original text of the event in the attribute
One of the greatest strengths of Humio is that the original data is kept and nothing is thrown away at ingest. This allows you to do free-text searching across all logs, and to extract virtual fields at query time - fields for parts of the data you did not even know would be important.
The timestamp of an event is represented in the
@timestamp field. This field
defines where the event is stored in the Humio’s database, and is what defined
wether an event is included in search results when searching a time range.
It needs special treatment when parsing incoming data at ingest time.
By default the Humio will display the content of the field
@rawstring in the
Event List. Sometimes this is not what you want, e.g the message could be very
long and the relevant information be at the end of
@rawstring, or you might
want to be able to see a single field.
You can fix this my assigning a value to the field
Let’s take an example: Say in our example data you only want to se the fields
url. You can use the format function and the
@display field to achieve this.
Say you have an access log for a web server, and don’t want to see all the details but just lines like:
GET /path/to/page POST /path/to/other/page
By setting the
@display field you can achieve using the following in you query:
@display := format("%s %s", field=[method, url])
As you can see we use a printf-like in format to format the resulting message, and now the entries in the Event List.
The type field is the name of the parser used to ingest the data.