ElasticSearch index unix timestamp

15
votes

I have to index documents containing a 'time' field whose value is an integer representing the number of seconds since epoch (aka unix timestamp).

I've been reading ES docs and have found this:

http://www.elasticsearch.org/guide/reference/mapping/date-format.html

But it seems that if I want to submit unix timestamps and want them stored in a 'date' field (integer field is not useful for me) I have only two options:

  • Implement my own date format
  • Convert to a supported format at the sender

Is there any other option I missed?

Thanks!

2
elasticsearch

2 Answers

20
votes

If you supply a mapping that tells ES the field is a date, it can use epoch millis as an input. If you want ES to auto-detect you'll have to provide ISO8601 or other discoverable format.

Update: I should also note that you can influence what strings ES will recognize as dates in your mapping. http://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-date-format.html

5
votes

In case you want to use Kibana, which I expect, and visualize according to the time of a log/entry you will need at least one field to be a date field.

Please note that you have to set the field as date type BEFORE you input any data into the /index/type. Otherwise it will be stored as long and unchangeable.

Simple example that can be pasted into the marvel/sense plugin:

# Make sure the index isn't there
DELETE /logger

# Create the index
PUT /logger

# Add the mapping of properties to the document type `mem`
PUT /logger/_mapping/mem
{
  "mem": {
    "properties": {
      "timestamp": {
        "type": "date"
      },
      "free": {
         "type": "long"
      }
    }
  }
}

# Inspect the newly created mapping
GET /logger/_mapping/mem

Run each of these commands in serie.

Generate free mem logs

Here is a simple script that echo to your terminal and logs to your local elasticsearch:

while (( 1==1 )); do memfree=`free -b|tail -n 1|tr -s ' ' ' '|cut -d ' ' -f4`; echo $load; curl -XPOST "localhost:9200/logger/mem" -d "{ \"timestamp\": `date +%s%3N`, \"free\": $memfree }"; sleep 1; done

Inspect data in elastic search

Paste this in your marvel/sense

GET /logger/mem/_search

Now you can move to Kibana and do some graphs. Kibana will autodetect your date field.