From c88dd392fe0f9fccd9f8c5193893d4ba02cb45eb Mon Sep 17 00:00:00 2001
From: Kacper Kula <kacper.kula@onfido.com>
Date: Thu, 18 Feb 2021 13:42:43 +0100
Subject: [PATCH] feat(environment): Added functionality to perist entries from
 different instance.

---
 README.md      | 5 +++++
 gatsby-node.js | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/README.md b/README.md
index 961bb3e..f8cb575 100644
--- a/README.md
+++ b/README.md
@@ -82,6 +82,8 @@ module.exports = {
         matchFields: ['slug', 'modified'], // Array<String> default: ['modified']
         concurrentQueries: false, // default: true
         skipIndexing: true, // default: false, useful for e.g. preview deploys or local development
+        useEnvironment: 'blog', // default: false, used in conjunction with enablePartialUpdates let you persist entries from different environment
+        environmentKey: 'product', // default: 'environment', key used when useEnvironment is set.
       },
     },
   ],
@@ -127,6 +129,9 @@ If you pass `replicaUpdateMode: 'replace'` in the index settings, you can choose
 
 If you pass `replicaUpdateMode: 'merge'` in the index settings, the replica settings will combine the replicas set on your dashboard with the additional ones you set via index settings here.
 
+### Persisting entries
+If you want to persist entries that are added to the index (for example added by the different gatsby instance if your index is combining several websites) you can set `useEnvironment` to unique string that represents given instance. All entries with different `environment` value will be ignored. You can change the key accordingly using `environmentKey`.
+
 ## Concurrent Queries
 
 Sometimes, on limited platforms like Netlify, concurrent queries to the same index can lead to unexpected results or hanging builds. Setting `concurrentQueries` to `false` makes it such that queries are run sequentially rather than concurrently, which may solve some concurrent access issues. Be aware that this option may make indexing take longer than it would otherwise.
diff --git a/gatsby-node.js b/gatsby-node.js
index cc8ba23..b817ab2 100644
--- a/gatsby-node.js
+++ b/gatsby-node.js
@@ -108,6 +108,8 @@ async function runIndexQueries(
     chunkSize = 1000,
     enablePartialUpdates = false,
     matchFields: mainMatchFields = ['modified'],
+    useEnvironment = false,
+    environmentKey = 'environment'
   } = config;
 
   setStatus(
@@ -168,6 +170,9 @@ async function runIndexQueries(
 
       // iterate over existing objects and compare to fresh data
       for (const [id, existingObj] of Object.entries(indexedObjects)) {
+        if (useEnvironment && existingObj[environmentKey] !== useEnvironment) {
+          continue;
+        }
         if (queryResultsMap.hasOwnProperty(id)) {
           // key matches fresh objects, so compare match fields
           const newObj = queryResultsMap[id];