EclipseCon - Building an IDE for Apache Cassandra
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This document discusses building an IDE for Apache Cassandra using Eclipse RCP, e4 and XText. It provides an overview of Cassandra's peer-to-peer architecture and linear scalability. It also describes Cassandra Query Language (CQL), including basic queries and table definitions. The document then discusses the DataStax DevCenter IDE, which is built using these technologies. It demonstrates features like validation, content assist and embedded editing support using XText. Finally, it discusses benefits and challenges of using the e4 framework within an Eclipse 3.x plugin.
EclipseCon - Building an IDE for Apache Cassandra
- 1. Building an IDE for Apache Cassandra With Eclipse RCP, e4 and XText Michaël Figuière Software Architect
- 2. © 2014 DataStax, All Rights Reserved. Cassandra Peer to Peer Architecture 2 Node Node Node Node Node Node Clients can reach any of the Cassandra nodes Every node have the same role, there’s no Master or Slave
- 3. © 2014 DataStax, All Rights Reserved. Cassandra Peer to Peer Architecture 3 Node Node Replica Replica Replica Node Each partition is stored in several Replicas to ensure durability and high availability
- 4. © 2014 DataStax, All Rights Reserved. Linear Scalability 4 Client Writes/s by Node Count - Replication Factor = 3
- 5. © 2014 DataStax, All Rights Reserved. Cassandra Query Language (CQL) • Similar to SQL, mostly a subset • Without joins, sub-queries, and aggregations • Primary Key contains: • A Partition Key used to select the partition that will store the Row • Some Clustering Columns, used to define how Rows should be grouped and sorted on the disk • Supports Collections • Supports User Defined Types (UDT) 5
- 6. © 2014 DataStax, All Rights Reserved. 6 CQL: Create Table CREATE TABLE users ( login text, name text, age int, ... PRIMARY KEY (login)); login is the partition key, it will be hashed and rows will be spread over the cluster on different partitions Just like in SQL!
- 7. © 2014 DataStax, All Rights Reserved. 7 CQL: Clustered Table CREATE TABLE mailbox ( login text, message_id timeuuid, interlocutor text, message text, PRIMARY KEY(login, message_id) ); message_id is a clustering column, it means that all the rows with a same login will be grouped and sorted by message_id on the disk A TimeUUID is a UUID that can be sorted chronologically
- 8. © 2014 DataStax, All Rights Reserved. 8 CQL: Queries SELECT * FROM mailbox WHERE login = jdoe AND message_id = '2014-09-25 16:00:00'; Get message by user and message_id (date) SELECT * FROM mailbox WHERE login = jdoe AND message_id <= '2014-09-25 16:00:00' AND message_id >= '2014-09-20 16:00:00'; Get message by user and date interval WHERE clauses can only be constraints on the primary key and range queries are not possible on the partition key
- 9. © 2014 DataStax, All Rights Reserved. DataStax DevCenter • Eclipse RCP standalone application • Eclipse 3.x + e4 • CQL editor based on Xtext • 1.0.0 in October 2013 - 1.3.0 March 2015 • Supports Cassandra 1.2 - 2.1 • Tens of thousands of downloads / month 9
- 11. © 2014 DataStax, All Rights Reserved. Xtext with CQL 11 ValidationCQL Grammar Content Assist Quick Fixes Syntax HighlightingFormatting Can be extracted as a standalone library
- 12. © 2014 DataStax, All Rights Reserved. 12 Validation and Quick Fix Validation @Fix(CqlConstants.KEYSPACE_EXIST) public void addIfNotExistst(final Issue issue, IssueResolutionAcceptor acceptor) { ... createKeyspaceStmt.setIfNotExists(true); ... } Quick Fix @Check public void checkKeyspaceNotExist(CreateKeyspaceStatement stmt) { if (context.isKeyspaceExistInDatabase(stmt.getKeyspaceEntity())) error(KEYSPACE_ALREADY_EXISTS, stmt, CqlConstants.KEYSPACE_EXIST); }
- 13. © 2014 DataStax, All Rights Reserved. Cassandra + Script Context 13
- 14. © 2014 DataStax, All Rights Reserved. Current Schema for Each Statement 14
- 15. © 2014 DataStax, All Rights Reserved. 15 Xtext Embedded Editor @Inject private EmbeddedEditorFactory factory; editor = factory .newEditor(resourceProvider) .readOnly() .withResourceValidator(resourceValidator) .processIssuesBy(issueProcessor) .withParent(container); partialEditor = editor.createPartialEditor(); Injected through Xtext’s Guice context The SWT Container the editor should be inserted in
- 16. © 2014 DataStax, All Rights Reserved. 16 Benefits of e4 Dependency Injection @Inject IEventBroker broker; public void doSomething() { broker.send(TOPIC, "some data"); } Events Handling @Inject public void create(Composite parent, IWorkbenchHelpSystem help) { Button button = ...; help.setHelp(button, "com.example.button.help.id"); } @Inject public void receive(@EventTopic(TOPIC) Object data) { fullRefresh(); }
- 17. © 2014 DataStax, All Rights Reserved. DevCenter and e4 • DevCenter cannot be a pure e4 application… • Relies on Xtext and Eclipse Editor • Eclipse IDE doesn’t rely on the e4 Application Model yet • …but can still use e4 through adapters on top of Eclipse 3.x 17
- 18. © 2014 DataStax, All Rights Reserved. E4 in a Eclipse 3.x Plugin 18 DIViewPart Adapter E4View Eclipse 3.x Plugin Eclipse technical code goes here Application logic sits here