Apache Solr - Solr HTTP Admin API: Collections API

Apache Solr | Solr HTTP Admin API: Collections API

Notes
List Collections
Create a Collection
Delete a Collection
Reload a Collection

Notes
See this page for more details about the Collections API:
https://lucene.apache.org/solr/guide/8_5/collections-api.html

List Collections

HTTP Request (URL):
http://localhost:8983/solr/admin/collections?action=List&omitHeader=true&wt=xml&indent=true

These parameters can be added to the request:
- omitHeader=true|false
- wt=json|xml
- indent=true|false

Java sample:

private void listCollections(final int jettyPort) throws IOException {
    final String url = "http://localhost:"
            + jettyPort
            + "/solr/admin/collections?action=List";

    final HttpGet request = new HttpGet(url);

    try (final CloseableHttpClient client = HttpClientBuilder.create().build();
            final CloseableHttpResponse response = client.execute(request)) {
        final HttpEntity entity = response.getEntity();

        System.out.println(IOUtils.toString(entity.getContent(), "UTF-8"));

        // close the content stream.
        EntityUtils.consumeQuietly(entity);
    }
}

Create a Collection

Create a collection (2 shards, 2 replicas), using an existing configuration directory in ZooKeeper ("_default").
Assuming you have at least 2 Solr instances up and running.

HTTP Request (URL):
http://localhost:8983/solr/admin/collections?action=CREATE&name=collection1&numShards=2&replicationFactor=2&maxShardsPerNode=2&collection.configName=_default

Output:

<response>
    <lst name="success">
        <lst name="192.168.2.33:8984_solr">
            <lst name="responseHeader">
                <int name="status">0</int>
                <int name="QTime">2176</int>
            </lst>
            <str name="core">collection1_shard1_replica_n1</str>
        </lst>
        <lst name="192.168.2.33:8984_solr">
            <lst name="responseHeader">
                <int name="status">0</int>
                <int name="QTime">2174</int>
            </lst>
            <str name="core">collection1_shard2_replica_n4</str>
        </lst>
        <lst name="192.168.2.33:8983_solr">
            <lst name="responseHeader">
                <int name="status">0</int>
                <int name="QTime">2557</int>
            </lst>
            <str name="core">collection1_shard1_replica_n2</str>
        </lst>
        <lst name="192.168.2.33:8983_solr">
            <lst name="responseHeader">
                <int name="status">0</int>
                <int name="QTime">2594</int>
            </lst>
            <str name="core">collection1_shard2_replica_n6</str>
        </lst>
    </lst>
</response>

Java sample:

private void createCollection(final int jettyPort, final String collectionName, final int numShards, final int numReplicas, final int maxShardsPerNode, final String configSetName) throws IOException {
    final String url = "http://localhost:"
            + jettyPort
            + "/solr/admin/collections?action=CREATE"
            + "&name=" + collectionName
            + "&numShards=" + numShards
            + "&replicationFactor=" + numReplicas
            + "&maxShardsPerNode=" + maxShardsPerNode
            + "&collection.configName=" + configSetName;

    final HttpGet request = new HttpGet(url);

    try (final CloseableHttpClient client = HttpClientBuilder.create().build();
            final CloseableHttpResponse response = client.execute(request)) {
        final HttpEntity entity = response.getEntity();

        System.out.println(IOUtils.toString(entity.getContent(), "UTF-8"));

        // close the content stream.
        EntityUtils.consumeQuietly(entity);
    }
}

Delete a Collection

You will get an error if you try to delete a collection that is part of aliases.
You have, first, to delete those aliases (or remove the collection from them) to be able to delete the collection.

HTTP Request (URL):
http://localhost:8983/solr/admin/collections?action=DELETE&name=collection1

Java sample:

private void deleteCollection(final int jettyPort, final String collectionName) throws IOException {
    final String url = "http://localhost:"
            + jettyPort
            + "/solr/admin/collections?action=DELETE"
            + "&name=" + collectionName;

    final HttpGet request = new HttpGet(url);

    try (final CloseableHttpClient client = HttpClientBuilder.create().build();
            final CloseableHttpResponse response = client.execute(request)) {
        final HttpEntity entity = response.getEntity();

        System.out.println(IOUtils.toString(entity.getContent(), "UTF-8"));

        // close the content stream.
        EntityUtils.consumeQuietly(entity);
    }
}

Reload a Collection

The "RELOAD" action can be used if you the change the collection configuration in ZooKeeper.

HTTP Request (URL):
http://localhost:8983/solr/admin/collections?action=RELOAD&name=collection1

Java sample:

private void reloadCollection(final int jettyPort, final String collectionName) throws IOException {
    final String url = "http://localhost:"
            + jettyPort
            + "/solr/admin/collections?action=RELOAD"
            + "&name=" + collectionName;

    final HttpGet request = new HttpGet(url);

    try (final CloseableHttpClient client = HttpClientBuilder.create().build();
            final CloseableHttpResponse response = client.execute(request)) {
        final HttpEntity entity = response.getEntity();

        System.out.println(IOUtils.toString(entity.getContent(), "UTF-8"));

        // close the content stream.
        EntityUtils.consumeQuietly(entity);
    }
}