update ES index on crawl

README.md

@@ -34,6 +34,9 @@ Though dockerized, backend development is easiest if you have the following inst
 - `docker-compose build`
 - `docker-compose up -d phoenix`
   - if you don't specify `phoenix`, it'll also start `gephi` which should only be run as a regular one-off job
+- Create the elasticsearch index:
+  - `iex -S mix app.start`
+  - `Elasticsearch.Index.hot_swap(Backend.Elasticsearch.Cluster, :instances)`
 
 ### Frontend
 
@@ -96,6 +99,9 @@ SHELL=/bin/bash
 
 10. (Optional) Set up caching with something like [dokku-nginx-cache](https://github.com/Aluxian/dokku-nginx-cache)
 
+Before the app starts running, make sure that the Elasticsearch index exists -- otherwise it'll create one called
+`instances`, which should be the name of the alias. Then it won't be able to hot swap if you reindex in the future.
+
 ## Acknowledgements
 
 [![NLnet logo](/nlnet-logo.png)](https://nlnet.nl/project/fediverse_space/)

backend/config/config.exs

@@ -23,7 +23,7 @@ config :backend, Backend.Repo, queue_target: 5000
 instances_config_path =
   if System.get_env("MIX_ENV") == "prod",
     do: "lib/backend-2.2.0/priv/elasticsearch/instances.json",
-    else: "instances.json"
+    else: "priv/elasticsearch/instances.json"
 
 config :backend, Backend.Elasticsearch.Cluster,
   url: "http://localhost:9200",

backend/lib/backend/crawler/crawler.ex

@@ -111,22 +111,26 @@ defmodule Backend.Crawler do
       end
 
     ## Update the instance we crawled ##
+    instance = %Instance{
+      domain: domain,
+      description: result.description,
+      version: result.version,
+      user_count: result.user_count,
+      status_count: result.status_count,
+      type: instance_type,
+      base_domain: get_base_domain(domain)
+    }
+
     Repo.insert!(
-      %Instance{
-        domain: domain,
-        description: result.description,
-        version: result.version,
-        user_count: result.user_count,
-        status_count: result.status_count,
-        type: instance_type,
-        base_domain: get_base_domain(domain)
-      },
+      instance,
       on_conflict:
         {:replace,
          [:description, :version, :user_count, :status_count, :type, :base_domain, :updated_at]},
       conflict_target: :domain
     )
 
+    Elasticsearch.put_document(Backend.Elasticsearch.Cluster, instance, "instances/_doc")
+
     # Save details of a new crawl
     curr_crawl =
       Repo.insert!(%Crawl{