cargo-metadata(1)
NAME
cargo-metadata — Machine-readable metadata about the current package
SYNOPSIS
cargo metadata [options]
DESCRIPTION
Output JSON to stdout containing information about the workspace members and resolved dependencies of the current package.
The format of the output is subject to change in futures versions of Cargo. It
is recommended to include the --format-version flag to future-proof your code
to ensure the output is in the format you are expecting. For more on the
expectations, see “Compatibility”.
See the cargo_metadata crate for a Rust API for reading the metadata.
OUTPUT FORMAT
Compatibility
Within the same output format version, the compatibility is maintained, except some scenarios. The following is a non-exhaustive list of changes that are not considered as incompatible:
- Adding new fields — New fields will be added when needed. Reserving this helps Cargo evolve without bumping the format version too often.
- Adding new values for enum-like fields — Same as adding new fields. It keeps metadata evolving without stagnation.
- Changing opaque representations — The inner representations of some fields are implementation details. For example, fields related to “Source ID” are treated as opaque identifiers to differentiate packages or sources. Consumers shouldn’t rely on those representations unless specified.
JSON format
The JSON output has the following format:
{
/* Array of all packages in the workspace.
It also includes all feature-enabled dependencies unless --no-deps is used.
*/
"packages": [
{
/* The name of the package. */
"name": "my-package",
/* The version of the package. */
"version": "0.1.0",
/* The Package ID for referring to the
package within the document and as the `--package` argument to many commands
*/
"id": "file:///path/to/my-package#0.1.0",
/* The license value from the manifest, or null. */
"license": "MIT/Apache-2.0",
/* The license-file value from the manifest, or null. */
"license_file": "LICENSE",
/* The description value from the manifest, or null. */
"description": "Package description.",
/* The source ID of the package, an "opaque" identifier representing
where a package is retrieved from. See "Compatibility" above for
the stability guarantee.
This is null for path dependencies and workspace members.
For other dependencies, it is a string with the format:
- "registry+URL" for registry-based dependencies.
Example: "registry+https://github.com/rust-lang/crates.io-index"
- "git+URL" for git-based dependencies.
Example: "git+https://github.com/rust-lang/cargo?rev=5e85ba14aaa20f8133863373404cb0af69eeef2c#5e85ba14aaa20f8133863373404cb0af69eeef2c"
- "sparse+URL" for dependencies from a sparse registry
Example: "sparse+https://my-sparse-registry.org"
The value after the `+` is not explicitly defined, and may change
between versions of Cargo and may not directly correlate to other
things, such as registry definitions in a config file. New source
kinds may be added in the future which will have different `+`
prefixed identifiers.
*/
"source": null,
/* Array of dependencies declared in the package's manifest. */
"dependencies": [
{
/* The name of the dependency. */
"name": "bitflags",
/* The source ID of the dependency. May be null, see
description for the package source.
*/
"source": "registry+https://github.com/rust-lang/crates.io-index",
/* The version requirement for the dependency.
Dependencies without a version requirement have a value of "*".
*/
"req": "^1.0",
/* The dependency kind.
"dev", "build", or null for a normal dependency.
*/
"kind": null,
/* If the dependency is renamed, this is the new name for
the dependency as a string. null if it is not renamed.
*/
"rename": null,
/* Boolean of whether or not this is an optional dependency. */
"optional": false,
/* Boolean of whether or not default features are enabled. */
"uses_default_features": true,
/* Array of features enabled. */
"features": [],
/* The target platform for the dependency.
null if not a target dependency.
*/
"target": "cfg(windows)",
/* The file system path for a local path dependency.
not present if not a path dependency.
*/
"path": "/path/to/dep",
/* A string of the URL of the registry this dependency is from.
If not specified or null, the dependency is from the default
registry (crates.io).
*/
"registry": null,
/* (unstable) Boolean flag of whether or not this is a pulbic
dependency. This field is only present when
`-Zpublic-dependency` is enabled.
*/
"public": false
}
],
/* Array of Cargo targets. */
"targets": [
{
/* Array of target kinds.
- lib targets list the `crate-type` values from the
manifest such as "lib", "rlib", "dylib",
"proc-macro", etc. (default ["lib"])
- binary is ["bin"]
- example is ["example"]
- integration test is ["test"]
- benchmark is ["bench"]
- build script is ["custom-build"]
*/
"kind": [
"bin"
],
/* Array of crate types.
- lib and example libraries list the `crate-type` values
from the manifest such as "lib", "rlib", "dylib",
"proc-macro", etc. (default ["lib"])
- all other target kinds are ["bin"]
*/
"crate_types": [
"bin"
],
/* The name of the target.
For lib targets, dashes will be replaced with underscores.
*/
"name": "my-package",
/* Absolute path to the root source file of the target. */
"src_path": "/path/to/my-package/src/main.rs",
/* The Rust edition of the target.
Defaults to the package edition.
*/
"edition": "2018",
/* Array of required features.
This property is not included if no required features are set.
*/
"required-features": ["feat1"],
/* Whether the target should be documented by `cargo doc`. */
"doc": true,
/* Whether or not this target has doc tests enabled, and
the target is compatible with doc testing.
*/
"doctest": false,
/* Whether or not this target should be built and run with `--test`
*/
"test": true
}
],
/* Set of features defined for the package.
Each feature maps to an array of features or dependencies it
enables.
*/
"features": {
"default": [
"feat1"
],
"feat1": [],
"feat2": []
},
/* Absolute path to this package's manifest. */
"manifest_path": "/path/to/my-package/Cargo.toml",
/* Package metadata.
This is null if no metadata is specified.
*/
"metadata": {
"docs": {
"rs": {
"all-features": true
}
}
},
/* List of registries to which this package may be published.
Publishing is unrestricted if null, and forbidden if an empty array. */
"publish": [
"crates-io"
],
/* Array of authors from the manifest.
Empty array if no authors specified.
*/
"authors": [
"Jane Doe <user@example.com>"
],
/* Array of categories from the manifest. */
"categories": [
"command-line-utilities"
],
/* Optional string that is the default binary picked by cargo run. */
"default_run": null,
/* Optional string that is the minimum supported rust version */
"rust_version": "1.56",
/* Array of keywords from the manifest. */
"keywords": [
"cli"
],
/* The readme value from the manifest or null if not specified. */
"readme": "README.md",
/* The repository value from the manifest or null if not specified. */
"repository": "https://github.com/rust-lang/cargo",
/* The homepage value from the manifest or null if not specified. */
"homepage": "https://rust-lang.org",
/* The documentation value from the manifest or null if not specified. */
"documentation": "https://doc.rust-lang.org/stable/std",
/* The default edition of the package.
Note that individual targets may have different editions.
*/
"edition": "2018",
/* Optional string that is the name of a native library the package
is linking to.
*/
"links": null,
}
],
/* Array of members of the workspace.
Each entry is the Package ID for the package.
*/
"workspace_members": [
"file:///path/to/my-package#0.1.0",
],
/* Array of default members of the workspace.
Each entry is the Package ID for the package.
*/
"workspace_default_members": [
"file:///path/to/my-package#0.1.0",
],
// The resolved dependency graph for the entire workspace. The enabled
// features are based on the enabled features for the "current" package.
// Inactivated optional dependencies are not listed.
//
// This is null if --no-deps is specified.
//
// By default, this includes all dependencies for all target platforms.
// The `--filter-platform` flag may be used to narrow to a specific
// target triple.
"resolve": {
/* Array of nodes within the dependency graph.
Each node is a package.
*/
"nodes": [
{
/* The Package ID of this node. */
"id": "file:///path/to/my-package#0.1.0",
/* The dependencies of this package, an array of Package IDs. */
"dependencies": [
"https://github.com/rust-lang/crates.io-index#bitflags@1.0.4"
],
/* The dependencies of this package. This is an alternative to
"dependencies" which contains additional information. In
particular, this handles renamed dependencies.
*/
"deps": [
{
/* The name of the dependency's library target.
If this is a renamed dependency, this is the new
name.
*/
"name": "bitflags",
/* The Package ID of the dependency. */
"pkg": "https://github.com/rust-lang/crates.io-index#bitflags@1.0.4"
/* Array of dependency kinds. Added in Cargo 1.40. */
"dep_kinds": [
{
/* The dependency kind.
"dev", "build", or null for a normal dependency.
*/
"kind": null,
/* The target platform for the dependency.
null if not a target dependency.
*/
"target": "cfg(windows)"
}
]
}
],
/* Array of features enabled on this package. */
"features": [
"default"
]
}
],
/* The root package of the workspace.
This is null if this is a virtual workspace. Otherwise it is
the Package ID of the root package.
*/
"root": "file:///path/to/my-package#0.1.0",
},
/* The absolute path to the build directory where Cargo places its output. */
"target_directory": "/path/to/my-package/target",
/* The version of the schema for this metadata structure.
This will be changed if incompatible changes are ever made.
*/
"version": 1,
/* The absolute path to the root of the workspace. */
"workspace_root": "/path/to/my-package"
/* Workspace metadata.
This is null if no metadata is specified. */
"metadata": {
"docs": {
"rs": {
"all-features": true
}
}
}
}
Notes:
- For
"id"field syntax, see Package ID Specifications in the reference.
OPTIONS
Output Options
--no-deps- Output information only about the workspace members and don’t fetch dependencies.
--format-versionversion- Specify the version of the output format to use. Currently
1is the only possible value. --filter-platformtriple- This filters the
resolveoutput to only include dependencies for the given target triple. Without this flag, the resolve includes all targets.Note that the dependencies listed in the “packages” array still includes all dependencies. Each package definition is intended to be an unaltered reproduction of the information within
Cargo.toml.
Feature Selection
The feature flags allow you to control which features are enabled. When no
feature options are given, the default feature is activated for every
selected package.
See the features documentation for more details.
-Ffeatures--featuresfeatures- Space or comma separated list of features to activate. Features of workspace
members may be enabled with
package-name/feature-namesyntax. This flag may be specified multiple times, which enables all specified features. --all-features- Activate all available features of all selected packages.
--no-default-features- Do not activate the
defaultfeature of the selected packages.
Display Options
-v--verbose- Use verbose output. May be specified twice for “very verbose” output which
includes extra output such as dependency warnings and build script output.
May also be specified with the
term.verboseconfig value. -q--quiet- Do not print cargo log messages.
May also be specified with the
term.quietconfig value. --colorwhen- Control when colored output is used. Valid values:
auto(default): Automatically detect if color support is available on the terminal.always: Always display colors.never: Never display colors.
May also be specified with the
term.colorconfig value.
Manifest Options
--manifest-pathpath- Path to the
Cargo.tomlfile. By default, Cargo searches for theCargo.tomlfile in the current directory or any parent directory. --locked- Asserts that the exact same dependencies and versions are used as when the
existing
Cargo.lockfile was originally generated. Cargo will exit with an error when either of the following scenarios arises:- The lock file is missing.
- Cargo attempted to change the lock file due to a different dependency resolution.
It may be used in environments where deterministic builds are desired, such as in CI pipelines.
--offline- Prevents Cargo from accessing the network for any reason. Without this
flag, Cargo will stop with an error if it needs to access the network and
the network is not available. With this flag, Cargo will attempt to
proceed without the network if possible.
Beware that this may result in different dependency resolution than online mode. Cargo will restrict itself to crates that are downloaded locally, even if there might be a newer version as indicated in the local copy of the index. See the cargo-fetch(1) command to download dependencies before going offline.
May also be specified with the
net.offlineconfig value. --frozen- Equivalent to specifying both
--lockedand--offline. --lockfile-pathPATH- Changes the path of the lockfile from the default (
<workspace_root>/Cargo.lock) to PATH. PATH must end withCargo.lock(e.g.--lockfile-path /tmp/temporary-lockfile/Cargo.lock). Note that providing--lockfile-pathwill ignore existing lockfile at the default path, and instead will either use the lockfile from PATH, or write a new lockfile into the provided PATH if it doesn’t exist. This flag can be used to run most commands in read-only directories, writing lockfile into the provided PATH.This option is only available on the nightly channel and requires the
-Z unstable-optionsflag to enable (see #14421).
Common Options
+toolchain- If Cargo has been installed with rustup, and the first argument to
cargobegins with+, it will be interpreted as a rustup toolchain name (such as+stableor+nightly). See the rustup documentation for more information about how toolchain overrides work. --configKEY=VALUE or PATH- Overrides a Cargo configuration value. The argument should be in TOML syntax of
KEY=VALUE, or provided as a path to an extra configuration file. This flag may be specified multiple times. See the command-line overrides section for more information. -CPATH- Changes the current working directory before executing any specified operations. This affects
things like where cargo looks by default for the project manifest (
Cargo.toml), as well as the directories searched for discovering.cargo/config.toml, for example. This option must appear before the command name, for examplecargo -C path/to/my-project build.This option is only available on the nightly channel and requires the
-Z unstable-optionsflag to enable (see #10098). -h--help- Prints help information.
-Zflag- Unstable (nightly-only) flags to Cargo. Run
cargo -Z helpfor details.
ENVIRONMENT
See the reference for details on environment variables that Cargo reads.
EXIT STATUS
0: Cargo succeeded.101: Cargo failed to complete.
EXAMPLES
-
Output JSON about the current package:
cargo metadata --format-version=1
SEE ALSO
cargo(1), cargo-pkgid(1), Package ID Specifications, JSON messages