Elastic Search when to add dynamic mappings - dynamic

Question

I've been having troubles with Elastic Search (ES) dynamic mappings. Seems like I'm in a catch-22. https://www.elastic.co/guide/en/elasticsearch/guide/current/custom-dynamic-mapping.html
The main goal is to store everything as a string that comes into ES.
What I've tried:
In ES you can't create a dynamic mapping until the index has been
created. Okay, makes sense.
I can't create an empty index, so if
the first item sent into the index is not a string, I can't
re-assign it... I won't know what type of object with be the first
item in the index, it could be any type, due to how the the app accepts a variety of objects/events.
So if I can't create the mapping ahead of time, and I can't insert an empty index to create the mapping, and I can't change the mapping after the fact, how do I deal with the first item if its NOT a string???
Here's what I'm currently doing (using the Javascript Client).
createESIndex = function (esClient){
esClient.index({
index: 'timeline-2015-11-21',
type: 'event',
body: event
},function (error, response) {
if (error) {
logger.log(logger.SEVERITY.ERROR, 'acceptEvent elasticsearch create failed with: '+ error + " req:" + JSON.stringify(event));
console.log(logger.SEVERITY.ERROR, 'acceptEvent elasticsearch create failed with: '+ error + " req:" + JSON.stringify(event));
res.status(500).send('Error saving document');
} else {
res.status(200).send('Accepted');
}
});
}
esClientLookup.getClient( function(esClient) {
esClient.indices.putTemplate({
name: "timeline-mapping-template",
body:{
"template": "timeline-*",
"mappings": {
"event": {
"dynamic_templates": [
{ "timestamp-only": {
"match": "#timestamp",
"match_mapping_type": "date",
"mapping": {
"type": "date",
}
}},
{ "all-others": {
"match": "*",
"match_mapping_type": "string",
"mapping": {
"type": "string",
}
}
}
]
}
}
}
}).then(function(res){
console.log("put template response: " + JSON.stringify(res));
createESIndex(esClient);
}, function(error){
console.log(error);
res.status(500).send('Error saving document');
});
});

Answer 1

Index templates to the rescue !! That's exactly what you need, the idea is to create a template of your index and as soon as you wish to store a document in that index, ES will create it for you with the mapping you gave (even dynamic ones)
curl -XPUT localhost:9200/_template/my_template -d '{
"template": "index_name_*",
"settings": {
"number_of_shards": 1
},
"mappings": {
"type_name": {
"dynamic_templates": [
{
"strings": {
"match": "*",
"match_mapping_type": "*",
"mapping": {
"type": "string"
}
}
}
],
"properties": {}
}
}
}'
Then when you index anything in an index whose name matches index_name_*, the index will be created with the dynamic mapping above.
For instance:
curl -XPUT localhost:9200/index_name_1/type_name/1 -d '{
"one": 1,
"two": "two",
"three": true
}'
That will create a new index called index_name_1 with a mapping type for type_name where all properties are string. You can verify that with
curl -XGET localhost:9200/index_name_1/_mapping/type_name
Response:
{
"index_name_1" : {
"mappings" : {
"type_name" : {
"dynamic_templates" : [ {
"strings" : {
"mapping" : {
"type" : "string"
},
"match" : "*",
"match_mapping_type" : "*"
}
} ],
"properties" : {
"one" : {
"type" : "string"
},
"three" : {
"type" : "string"
},
"two" : {
"type" : "string"
}
}
}
}
}
}
Note that if you're willing to do this via the Javascript API, you can use the indices.putTemplate call.

Answer 2

export const user = {
email: {
type: 'text',
},
};
export const activity = {
date: {
type: 'text',
},
};
export const common = {
name: {
type: 'text',
},
};
import { Client } from '#elastic/elasticsearch';
import { user } from './user';
import { activity } from './activity';
import { common } from './common';
export class UserDataFactory {
private schema = {
...user,
...activity,
...common,
relation_type: {
type: 'join',
eager_global_ordinals: true,
relations: {
parent: ['activity'],
},
},
};
constructor(private client: Client) {
Object.setPrototypeOf(this, UserDataFactory.prototype);
}
async create() {
const settings = {
settings: {
analysis: {
normalizer: {
useLowercase: {
filter: ['lowercase'],
},
},
},
},
mappings: {
properties: this.schema,
},
};
const { body } = await this.client.indices.exists({
index: ElasticIndex.UserDataFactory,
});
await Promise.all([
await (async (client) => {
await new Promise(async function (resolve, reject) {
if (!body) {
await client.indices.create({
index: ElasticIndex.UserDataFactory,
});
}
resolve({ body });
});
})(this.client),
]);
await this.client.indices.close({ index: ElasticIndex.UserDataFactory });
await this.client.indices.putSettings({
index: ElasticIndex.UserDataFactory,
body: settings,
});
await this.client.indices.open({
index: ElasticIndex.UserDataFactory,
});
await this.client.indices.putMapping({
index: ElasticIndex.UserDataFactory,
body: {
dynamic: 'strict',
properties: {
...this.schema,
},
},
});
}
}
wrapper.ts
class ElasticWrapper {
private _client: Client = new Client({
node: process.env.elasticsearch_node,
auth: {
username: 'elastic',
password: process.env.elasticsearch_password || 'changeme',
},
ssl: {
ca: process.env.elasticsearch_certificate,
rejectUnauthorized: false,
},
});
get client() {
return this._client;
}
}
export const elasticWrapper = new ElasticWrapper();
index.ts
new UserDataFactory(elasticWrapper.client).create();