Heroic

A scalable time series database based on Cassandra and Elasticsearch. Go to https://spotify.github.io/heroic/ for documentation, please join #heroic at Freenode if you need help or want to chat.

Stability Disclaimer: Heroic is an evolving project, and should in its current state be considered unstable. Do not use in production unless you are willing to spend time with it, experiment and contribute. Not doing so might result in losing your data to goblins.

It is currently not on a release schedule and is not versioned. At Spotify we rely on multiple release forks that we actively maintain and flip between.

Building

Heroic requires Java 8, and is built using maven:

$ mvn clean package

This will cause the heroic-dist module to produce a shaded jar that contains all required dependencies.

Speedy Building

For a speedy build without tests and checks, you can run:

$ mvn clean package -D findbugs.skip=true -D checkstyle.skip=true -D maven.test.skip=true

It is strongly recommended that you run through findbugs and checkstyle before setting up a pull request.

Building a Debian Package

This project does not provide a single debian package, this is primarily because the current nature of the service (alpha state) does not mesh well with stable releases.

Instead, you are encouraged to build your own using the provided scripts in this project.

First run the prepare-sources script:

$ debian/bin/prepare-sources myrel 1

myrel will be the name of your release, it will be part of your package name debian-myrel, it will also be suffixed to all helper tools (e.g. heroic-myrel).

For the next step you'll need a Debian environment:

$ dpkg-buildpackage -uc -us

If you encounter problems, you can troubleshoot the build with DH_VERBOSE:

$ env DH_VERBOSE=1 dpkg-buildpackage -uc -us

Hacking

• Using Eclipse

Module Orientation

The Heroic project is split into a couple of modules.

The most critical one is heroic-component. It contains interfaces, value objects, and the basic set of dependencies necessary to glue different components together.

Submodules include metric, suggest, metadata, and aggregation. The first three contain various implementations of the given backend type, while the latter provides aggregation methods.

heroic-core contains the com.spotify.heroic.HeroicCore class which is the central building block for setting up a Heroic instance.

heroic-elasticsearch-utils is a collection of utilities for interacting with Elasticsearch. This is separate since we have more than one backend that needs to talk with elasticsearch.

heroic-parser provides an Antlr4 implementation of com.spotify.heroic.grammar.QueryParser, which is used to parse the Heroic DSL.

heroic-shell contains com.spotify.heroic.HeroicShell, a shell capable of either running a standalone, or connecting to an existing Heroic instance for administration.

heroic-all contains dependencies and references to all modules that makes up a Heroic distribution. This is also where profiles are defined since they need to have access to all dependencies.

Anything in the repackaged directory is dependencies that include one or more Java packages that must be relocated to avoid conflicts. These are exported under the com.spotify.heroic.repackaged groupId.

Finally there is heroic-dist, a small project that depends on heroic-all, heroic-shell, and a logging implementation. Here is where everything is bound together into a distribution — a shaded jar. It also provides the entry-point for services, namely com.spotify.heroic.HeroicService.

Bypassing Validation

To bypass automatic formatting and checkstyle validation you can use the following stanza:

// @formatter:off
final List<String> list = ImmutableList.of(
   "Welcome to...",
   "... The Wild West"
);
// @formatter:on

To bypass a FindBugs error, you should use the @SupressFBWarnings annotation.

@SupressFBWarnings(value="FINDBUGS_ERROR_CODE", justification="I Know Better Than FindBugs")
public class IKnowBetterThanFindbugs() {
    // ...
}

HeroicShell

Heroic comes with a shell that contains many useful tasks, these can either be run in a readline-based shell with some basic completions and history, or standalone.

You can use the following helper script to run the shell directly from the project.

$ tools/heroic-shell [opts]

There are a few interesting options available, most notably is --connect that allows the shell to connect to a remote heroic instance.

See -h for a full listing of options.

You can run individual tasks in standalone mode, giving you a bit more options (like redirecting output) through the following.

$ tools/heroic-shell <heroic-options> -- com.spotify.heroic.shell.task.<task-name> <task-options>

There are also profiles that can be activated with the -P <profile> switch, available profiles are listed in --help.