The Integrator Development Kit (IDK) archive contains the Fuchsia-specific libraries, FIDL interfaces, and tools required to start building and running programs for Fuchsia.
This IDK is the public definition of the Fuchsia platform. It is intentionally independent from specific build environment and targets integration and engprod teams integrating Fuchsia into specific developer environments. For example, it does not contain any build system, favor any toolchain, or provide standard non-Fuchsia libraries such as for crypto or graphics. Instead, it provides metadata accurately describing its various parts, so that the IDK is processed and augmented with specific tooling and support libraries to create the end-to-end development experience.
Most developers who wish to build something for Fuchsia should not need to deal directly with the IDK. They will instead consume a transformed version of it, for instance within the development environment and ecosystem supporting a given language runtime. Maintainers of development environments who wish to add support for Fuchsia are the main audience for the IDK. See Integrating the Core SDK for a description of how to process this IDK.
As such, the Fuchsia IDK is the representation of the Fuchsia platform developers' contract with other developers who work with Fuchsia. While that contract is absolutely necessary, as this IDK contains the very bits that are unique to Fuchsia, it is not sufficient and will be complemented by other "contracts". The Fuchsia IDK is mirroring the Fuchsia platform in that respect: highly composable and extensible, with a clear separation of concerns.
Structure
From this point on, the root of the IDK archive will be referred to as //.
Metadata
Metadata is present throughout this IDK in the form of JSON files.
Every element in this IDK has its own metadata file: for example, a FIDL library
//fidl/fuchsia.foobar has its metadata encoded in
//fidl/fuchsia.foobar/meta.json.
Every metadata file follows a JSON schema available under //meta/schemas: for
example, a FIDL library's metadata file conforms to
//meta/schemas/fidl_library.json.
Schemas act as the documentation for the metadata and may be used to facilitate
the IDK ingestion process. See understanding metadata.
Documentation
General documentation is available under //docs in the IDK distribution, or
online at fuchsia.dev/fuchsia-src/docs/development/idk.
Some individual IDK elements will also provide documentation directly under the
path where they are hosted in the IDK.
Target prebuilts
Target prebuilts are hosted under //arch/<architecture>.
This includes a full-fledged sysroot for each available architecture.
Source libraries
The IDK contains sources for a large number of FIDL libraries (under
//fidl) as well as a few C/C++ libraries (under //pkg). See compiling C/C++
for details.
Host tools
Multiple host-side tools can be found under //tools.
This includes tools for building programs, deploying to a device, debugging,
etc...
Some information about how to use these tools can be found under //docs.
Specifically:
Images
//device contains metadata describing device configurations matching a given
version of the IDK.
This metadata contains pointers to images that can be paved onto said devices.
See working with devices for how to interact with a device
running Fuchsia.