What is the best way to query the document closest to a date-time on elasticsearch? - datetime

Question

I need to retrieve the document that has the closest geo location and date-time to the request, so I'm not looking for a match of the date-time, but the closest one. I solved it using a custom script, however I'm guessing there might be a better way to do it, similar to the way I'm filtering the geo location based on a location and a distance.
Here's my code (in python):
query = {
"query": {
"function_score": {
"boost_mode": "replace",
"query": {
"filtered": {
"query" : {
"match_all" : {}
},
"filter" : {
"geo_distance" : {
"distance" : "10km",
"location" : json.loads(self.request.body)["location"]
}
}
}
},
"script_score": {
"lang": "groovy",
"script_file": "calculate-score",
"params": {
"stamp": json.loads(self.request.body)["stamp"]
}
}
}
},
"sort": [
{"_score": "asc"}
],
"size": 1
}
response = requests.get('http://localhost:9200/meteo/meteo/_search', data=json.dumps(query))
The custom calculate-score.groovy script contains the following:
abs(new java.text.SimpleDateFormat("yyyy-MM-dd\'T\'HH:mm").parse(stamp).getTime() - doc["stamp"].date.getMillis()) / 60000
The script returns the score as the absolute difference in minutes between the document date-time and the requested date-time.
Is there any other way to achieve this?

Answer 1

You should be able to use function_score to do this.
You could use the decay functions mentioned in the doucmentation to give a larger score to documents closer to the origin timestamp. Below is the example
where the scale=28800 mins i.e 20d.
Example:
put test
put test/test/_mapping
{
"properties": {
"stamp": {
"type": "date",
"format": "dateOptionalTime"
}
}
}
put test/test/1
{
"stamp":"2015-10-15T00:00"
}
put test/test/2
{
"stamp":"2015-10-15T12:00"
}
post test/_search
{
"query": {
"function_score": {
"functions": [
{
"linear": {
"stamp" : {
"origin": "now",
"scale": "28800m"
}
}
}
],
"score_mode" : "multiply",
"boost_mode": "multiply",
"query": {
"match_all": {}
}
}
}
}