* Allow the Trogdor agent to be started in "exec mode", where it simply
runs a single task and exits after it is complete.
* For AgentClient and CoordinatorClient, allow the user to pass the path
to a file containing JSON, instead of specifying the JSON object in the
command-line text itself. This means that we can get rid of the bash
scripts whose only function was to load task specs into a bash string
and run a Trogdor command.
* Print dates and times in a human-readable way, rather than as numbers
of milliseconds.
* When listing tasks or workers, output human-readable tables of
information.
* Allow the user to filter on task ID name, task ID pattern, or task
state.
* Support a --json flag to provide raw JSON output if desired.
Reviewed-by: David Arthur <mumrah@gmail.com>, Stanislav Kozlovski <stanislav_kozlovski@outlook.com>
This patch adds a framework to automatically generate the request/response classes for Kafka's protocol. The code will be updated to use the generated classes in follow-up patches. Below is a brief summary of the included components:
**buildSrc/src**
The message generator code is here. This code is automatically re-run by gradle when one of the schema files changes. The entire directory is processed at once to minimize the number of times we have to start a new JVM. We use Jackson to translate the JSON files into Java objects.
**clients/src/main/java/org/apache/kafka/common/protocol/Message.java**
This is the interface implemented by all automatically generated messages.
**clients/src/main/java/org/apache/kafka/common/protocol/MessageUtil.java**
Some utility functions used by the generated message code.
**clients/src/main/java/org/apache/kafka/common/protocol/Readable.java, Writable.java, ByteBufferAccessor.java**
The generated message code uses these classes for writing to a buffer.
**clients/src/main/message/README.md**
This README file explains how the JSON schemas work.
**clients/src/main/message/\*.json**
The JSON files in this directory implement every supported version of every Kafka API. The unit tests automatically validate that the generated schemas match the hand-written schemas in our code. Additionally, there are some things like request and response headers that have schemas here.
**clients/src/main/java/org/apache/kafka/common/utils/ImplicitLinkedHashSet.java**
I added an optimization here for empty sets. This is useful here because I want all messages to start with empty sets by default prior to being loaded with data. This is similar to the "empty list" optimizations in the `java.util.ArrayList` class.
Reviewers: Stanislav Kozlovski <stanislav_kozlovski@outlook.com>, Ismael Juma <ismael@juma.me.uk>, Bob Barrett <bob.barrett@outlook.com>, Jason Gustafson <jason@confluent.io>
Colin Patrick McCabe
Ewen Cheslack-Postava
Ivan Lyutov
Jun Rao