[GitHub] [incubator-iceberg] rdblue commented on a change in pull request #416: Adding docs on how to use custom catalog with iceberg

[GitBox <gi...@apache.org>]

rdblue commented on a change in pull request #416: Adding docs on how to use custom catalog with iceberg
URL: https://github.com/apache/incubator-iceberg/pull/416#discussion_r317813862
 
 

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 File path: site/docs/custom-catalog.md
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 @@ -0,0 +1,138 @@
+# Custom Catalog Implementation
+
+It's possible to read an iceberg table either from an hdfs path or from a hive table. It's also possible to use a custom metastore in place of hive. The steps to do that are as follows.
+
+- [Custom TableOperations](#custom-table-operations-implementation)
+- [Custom Catalog](#custom-table-implementation)
+- [Custom IcebergSource](#custom-icebergsource)
+
+### Custom table operations implementation
+Extend `BaseMetastoreTableOperations` to provide implementation on how to read and write metadata
+
+Example:
+```java
+
+class CustomTableOperations extends BaseMetastoreTableOperations {
+    private String dbName;
+    private String tableName;
+    private Configuration conf;
+    
+    protected CustomTableOperations(Configuration conf, String dbName, String tableName) {
+        super(conf);
+        this.conf = conf;
+        this.dbName = dbName;
+        this.tableName = tableName;
+    }
+    
+    // The refresh method should provide implementation on how to get the metadata location
+    @Override
+    public TableMetadata refresh() {
+    
+    // Example custom service which returns the metadata location given a dbName and tableName
+    val metadataLocation = CustomService.getMetadataForTable(conf, dbName, tableName)
 
 Review comment:
   Nit: Looks like indentation is off in this file.

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