# Synonyms with FSCrawler **URL:** \ **Category:** Elasticsearch\ **Created:** [July 3, 2025, 5:31pm UTC](https://discuss.elastic.co/t/synonyms-with-fscrawler/379785 "2025-07-03T17:31:34Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![AndreAT](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/andreat/32/140410_2.png) [@AndreAT](https://discuss.elastic.co/u/AndreAT)\ **Post date:** [July 3, 2025, 5:31pm UTC](https://discuss.elastic.co/t/synonyms-with-fscrawler/379785/1 "2025-07-03T17:31:35Z")
Hi, I like to use synonym\_path to assign a couple of synonyms to optimize my search. My enviroment is setup with Elasticsearch 8.15.1 and FSCrawler and after some study I figure out that I can't add mapping as done in common tuturials as there's already a mapper assigned (by FSCrawler I think). So when I try ```auto PUT /my_index/_mapping { "properties": { "content": { "type": "text", "analyzer": "my_synonym_analyzer" } } } ``` I get an error ```auto { "error": { "root_cause": [ { "type": "mapper_exception", "reason": "analyzer [my_synonym_analyzer] contains filters [my_synonym_filter] that are not allowed to run in index time mode." } ], "type": "mapper_parsing_exception", "reason": "Failed to parse mapping: analyzer [my_synonym_analyzer] contains filters [my_synonym_filter] that are not allowed to run in index time mode.", "caused_by": { "type": "mapper_exception", "reason": "analyzer [my_synonym_analyzer] contains filters [my_synonym_filter] that are not allowed to run in index time mode." } }, "status": 400 } ``` My issue is now to understand how I can handle to use my own synonyms. Tutorials are rare and/or outdated and I'm a novice with Elastic/FSCrawler. So what do you recommend is the best and a simple way to use own synonyms with Elasticsearch 8.15.1 and FSCrawler. Thank you, Andre ---
**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\ **Post date:** [July 3, 2025, 7:58pm UTC](https://discuss.elastic.co/t/synonyms-with-fscrawler/379785/2 "2025-07-03T19:58:51Z")
You need to update the component templates. Have a look at [Elasticsearch settings — FSCrawler 2.10-SNAPSHOT documentation](https://fscrawler.readthedocs.io/en/latest/admin/fs/elasticsearch.html#creating-your-own-mapping-analyzers). Note that you must reindex then. Also make sure that you are using the latest 2.10-SNAPSHOT. ---
**Author:** ![AndreAT](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/andreat/32/140410_2.png) [@AndreAT](https://discuss.elastic.co/u/AndreAT)\ **Post date:** [July 3, 2025, 8:34pm UTC](https://discuss.elastic.co/t/synonyms-with-fscrawler/379785/3 "2025-07-03T20:34:41Z")
Thank you, I read this page but don't get it. > If you want to define your own index settings and mapping to set analyzers for example, you can update the needed component template **before starting the FSCrawler**. What does **before starting the FSCrawler** means? I have to delete the index and use before I first run of FSCrawler? But in this case `PUT _component_template/fscrawler_mapping_content_semantic` won't work because of missing fscrawler settings, will it? The setting **"copy\_to": "content\_semantic"** I've never meet before in any sample. Is it requiered in any case? ---
**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\ **Post date:** [July 4, 2025, 1:04pm UTC](https://discuss.elastic.co/t/synonyms-with-fscrawler/379785/4 "2025-07-04T13:04:01Z")
Here are the steps (please note that **this will remove any existing data** ). If you don't have a trial or commercial license or running on cloud, then you don't have access to semantic search. I will assume that you don't do semantic search in the following instructions. I suppose here that you have already ran FSCrawler at least once before and that the templates have been installed already. This is something you can check by running: ```auto GET _component_template/fscrawler* ``` This should gives you a non empty list of components. So, you want to add synonyms. The first thing to do is to add it to the existing "content" component template named `fscrawler_mapping_content`: ```auto PUT _component_template/fscrawler_mapping_content { "template": { "settings": { "analysis": { "filter": { "my_synonym_filter": { "type": "synonym", "synonyms_set": "my-synonym-set", "updateable": true } }, "analyzer": { "my_synonym_analyzer": { "tokenizer": "standard", "filter": [ "lowercase", "my_synonym_filter" ] } } } }, "mappings": { "properties": { "content": { "type": "text", "analyzer": "my_synonym_analyzer" } } } } } ``` Then you need to tell FSCrawler not to push anymore its internal templates, otherwise your change will be overwritten. ```auto elasticsearch: push_templates: false ``` Then you need to remove the existing data. Let's assume that you used the default settings and that the index name is `fscrawler`: ```auto DELETE fscrawler ``` Then you can start again fscrawler with the `--restart` option. And I think this should work well. I did not test this but let me know if you have any trouble. ---
**Author:** ![AndreAT](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/andreat/32/140410_2.png) [@AndreAT](https://discuss.elastic.co/u/AndreAT)\ **Post date:** [July 7, 2025, 6:18pm UTC](https://discuss.elastic.co/t/synonyms-with-fscrawler/379785/5 "2025-07-07T18:18:19Z")
Amazing, thank you very much. I get that template is transmited from FSCrawler to ES and there'll be changed. There's a last issue with the request > [@dadoonet](#): > > ```auto > PUT _component_template/fscrawler_mapping_content > { > "template": { > "settings": { > "analysis": { > "filter": { > "my_synonym_filter": { > "type": "synonym", > "synonyms_set": "my-synonym-set", > "updateable": true > } > }, > "analyzer": { > "my_synonym_analyzer": { > "tokenizer": "standard", > "filter": [ > "lowercase", > "my_synonym_filter" > ] > } > } > } > } > }, > "mappings": { > "properties": { > "content": { > "type": "text", > "analyzer": "my_synonym_analyzer" > } > } > } > } > > ``` as it returns ```auto { "error": { "root_cause": [ { "type": "x_content_parse_exception", "reason": "[2:3] [component_template] unknown field [mappings]" } ], "type": "x_content_parse_exception", "reason": "[2:3] [component_template] unknown field [mappings]" }, "status": 400 } ``` Without the **"mappings"** part it runs fine but I expect the analyser has to be mapped too the template? Is something missing? ---
**Author:** ![dadoonet](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/dadoonet/32/137187_2.png) [@dadoonet](https://discuss.elastic.co/u/dadoonet)\ **Post date:** [July 7, 2025, 8:24pm UTC](https://discuss.elastic.co/t/synonyms-with-fscrawler/379785/6 "2025-07-07T20:24:40Z")
Ha sorry. It was wrong. Try this one. ```auto PUT _component_template/fscrawler_mapping_content { "template": { "settings": { "analysis": { "filter": { "my_synonym_filter": { "type": "synonym", "synonyms_set": "my-synonym-set", "updateable": true } }, "analyzer": { "my_synonym_analyzer": { "tokenizer": "standard", "filter": [ "lowercase", "my_synonym_filter" ] } } } }, "mappings": { "properties": { "content": { "type": "text", "analyzer": "my_synonym_analyzer" } } } } } ``` ---
**Author:** ![AndreAT](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/andreat/32/140410_2.png) [@AndreAT](https://discuss.elastic.co/u/AndreAT)\ **Post date:** [July 7, 2025, 9:14pm UTC](https://discuss.elastic.co/t/synonyms-with-fscrawler/379785/7 "2025-07-07T21:14:50Z")
Yes, that it, thank you. It's really great to make it work after a long time and I learned about how it work in general. Anyway I note that there's much more to study for a deeper understanding ...