Crate cargo_metadata

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Expand description

Structured access to the output of cargo metadata and cargo --message-format=json. Usually used from within a cargo-* executable

See the cargo book for details on cargo itself.


let mut args = std::env::args().skip_while(|val| !val.starts_with("--manifest-path"));

let mut cmd = cargo_metadata::MetadataCommand::new();
let manifest_path = match {
    Some(ref p) if p == "--manifest-path" => {
    Some(p) => {
    None => {}

let _metadata = cmd.exec().unwrap();

Pass features flags

use cargo_metadata::{MetadataCommand, CargoOpt};

let _metadata = MetadataCommand::new()

Parse message-format output:

use std::process::{Stdio, Command};
use cargo_metadata::Message;

let mut command = Command::new("cargo")
    .args(&["build", "--message-format=json-render-diagnostics"])

let reader = std::io::BufReader::new(command.stdout.take().unwrap());
for message in cargo_metadata::Message::parse_stream(reader) {
    match message.unwrap() {
        Message::CompilerMessage(msg) => {
            println!("{:?}", msg);
        Message::CompilerArtifact(artifact) => {
            println!("{:?}", artifact);
        Message::BuildScriptExecuted(script) => {
            println!("{:?}", script);
        Message::BuildFinished(finished) => {
            println!("{:?}", finished);
        _ => () // Unknown message

let output = command.wait().expect("Couldn't get cargo's exit status");


pub use camino;
pub use semver;


This module contains Diagnostic and the types/functions it uses for deserialization.


A compiler-generated file.
Profile settings used to determine which compiler flags to use for a target.
Final result of a build.
Output of a build script execution.
Message left by the compiler
Information about a dependency kind.
A dependency of the main crate
An iterator of Messages.
Starting point for metadata returned by cargo metadata
A builder for configurating cargo metadata invocation.
A node in a dependencies graph
A dependency in a node
One or more crates described by a single Cargo.toml
An “opaque” identifier for a package. It is possible to inspect the repr field, if the need arises, but its precise format is an implementation detail and is subject to change.
A dependency graph
The source of a package such as
A single target (lib, bin, example, …) provided by a crate


Cargo features flags
Dependencies can come in three kinds
The Rust edition
Error returned when executing/parsing cargo metadata fails.
A cargo message


Creates an iterator of Message from a Read outputting a stream of JSON messages. For usage information, look at the top-level documentation.

Type Definitions

Custom result type for cargo_metadata::Error