Add `--output-file` to `uv export` (#7109)

## Summary

Closes https://github.com/astral-sh/uv/issues/7058.

crates/uv-cli/src/lib.rs

@@ -2966,6 +2966,10 @@ pub struct ExportArgs {
     #[arg(long, overrides_with("hashes"))]
     pub no_hashes: bool,
 
+    /// Write the compiled requirements to the given `requirements.txt` file.
+    #[arg(long, short)]
+    pub output_file: Option<PathBuf>,
+
     /// Assert that the `uv.lock` will remain unchanged.
     ///
     /// Requires that the lockfile is up-to-date. If the lockfile is missing or

crates/uv/src/commands/mod.rs

@@ -1,8 +1,11 @@
-use std::time::Duration;
+use anstream::AutoStream;
-use std::{fmt::Display, fmt::Write, process::ExitCode};
-
 use anyhow::Context;
 use owo_colors::OwoColorize;
+use std::borrow::Cow;
+use std::io::stdout;
+use std::path::Path;
+use std::time::Duration;
+use std::{fmt::Display, fmt::Write, process::ExitCode};
 
 pub(crate) use build::build;
 pub(crate) use cache_clean::cache_clean;
@@ -198,3 +201,54 @@ pub(crate) struct SharedState {
     /// The downloaded distributions.
     pub(crate) in_flight: InFlight,
 }
+
+/// A multicasting writer that writes to both the standard output and an output file, if present.
+#[allow(clippy::disallowed_types)]
+struct OutputWriter<'a> {
+    stdout: Option<AutoStream<std::io::Stdout>>,
+    output_file: Option<&'a Path>,
+    buffer: Vec<u8>,
+}
+
+#[allow(clippy::disallowed_types)]
+impl<'a> OutputWriter<'a> {
+    /// Create a new output writer.
+    fn new(include_stdout: bool, output_file: Option<&'a Path>) -> Self {
+        let stdout = include_stdout.then(|| AutoStream::<std::io::Stdout>::auto(stdout()));
+        Self {
+            stdout,
+            output_file,
+            buffer: Vec::new(),
+        }
+    }
+
+    /// Write the given arguments to both standard output and the output buffer, if present.
+    fn write_fmt(&mut self, args: std::fmt::Arguments<'_>) -> std::io::Result<()> {
+        use std::io::Write;
+
+        // Write to the buffer.
+        if self.output_file.is_some() {
+            self.buffer.write_fmt(args)?;
+        }
+
+        // Write to standard output.
+        if let Some(stdout) = &mut self.stdout {
+            write!(stdout, "{args}")?;
+        }
+
+        Ok(())
+    }
+
+    /// Commit the buffer to the output file.
+    async fn commit(self) -> std::io::Result<()> {
+        if let Some(output_file) = self.output_file {
+            // If the output file is an existing symlink, write to the destination instead.
+            let output_file = fs_err::read_link(output_file)
+                .map(Cow::Owned)
+                .unwrap_or(Cow::Borrowed(output_file));
+            let stream = anstream::adapter::strip_bytes(&self.buffer).into_vec();
+            uv_fs::write_atomic(output_file, &stream).await?;
+        }
+        Ok(())
+    }
+}

crates/uv/src/commands/pip/compile.rs

@@ -1,9 +1,7 @@
-use std::borrow::Cow;
 use std::env;
-use std::io::stdout;
 use std::path::Path;
 
-use anstream::{eprint, AutoStream};
+use anstream::eprint;
 use anyhow::{anyhow, Result};
 use itertools::Itertools;
 use owo_colors::OwoColorize;
@@ -43,7 +41,7 @@ use uv_warnings::warn_user;
 
 use crate::commands::pip::loggers::DefaultResolveLogger;
 use crate::commands::pip::{operations, resolution_environment};
-use crate::commands::ExitStatus;
+use crate::commands::{ExitStatus, OutputWriter};
 use crate::printer::Printer;
 
 /// Resolve a set of requirements into a set of pinned versions.
@@ -621,54 +619,3 @@ fn cmd(
         .join(" ");
     format!("uv {args}")
 }
-
-/// A multicasting writer that writes to both the standard output and an output file, if present.
-#[allow(clippy::disallowed_types)]
-struct OutputWriter<'a> {
-    stdout: Option<AutoStream<std::io::Stdout>>,
-    output_file: Option<&'a Path>,
-    buffer: Vec<u8>,
-}
-
-#[allow(clippy::disallowed_types)]
-impl<'a> OutputWriter<'a> {
-    /// Create a new output writer.
-    fn new(include_stdout: bool, output_file: Option<&'a Path>) -> Self {
-        let stdout = include_stdout.then(|| AutoStream::<std::io::Stdout>::auto(stdout()));
-        Self {
-            stdout,
-            output_file,
-            buffer: Vec::new(),
-        }
-    }
-
-    /// Write the given arguments to both standard output and the output buffer, if present.
-    fn write_fmt(&mut self, args: std::fmt::Arguments<'_>) -> std::io::Result<()> {
-        use std::io::Write;
-
-        // Write to the buffer.
-        if self.output_file.is_some() {
-            self.buffer.write_fmt(args)?;
-        }
-
-        // Write to standard output.
-        if let Some(stdout) = &mut self.stdout {
-            write!(stdout, "{args}")?;
-        }
-
-        Ok(())
-    }
-
-    /// Commit the buffer to the output file.
-    async fn commit(self) -> std::io::Result<()> {
-        if let Some(output_file) = self.output_file {
-            // If the output file is an existing symlink, write to the destination instead.
-            let output_file = fs_err::read_link(output_file)
-                .map(Cow::Owned)
-                .unwrap_or(Cow::Borrowed(output_file));
-            let stream = anstream::adapter::strip_bytes(&self.buffer).into_vec();
-            uv_fs::write_atomic(output_file, &stream).await?;
-        }
-        Ok(())
-    }
-}

crates/uv/src/commands/project/export.rs

@@ -1,5 +1,6 @@
 use anyhow::{Context, Result};
 use owo_colors::OwoColorize;
+use std::path::PathBuf;
 
 use uv_cache::Cache;
 use uv_client::Connectivity;
@@ -13,7 +14,7 @@ use uv_workspace::{DiscoveryOptions, MemberDiscovery, VirtualProject, Workspace}
 use crate::commands::pip::loggers::DefaultResolveLogger;
 use crate::commands::project::lock::do_safe_lock;
 use crate::commands::project::{FoundInterpreter, ProjectError};
-use crate::commands::{pip, ExitStatus};
+use crate::commands::{pip, ExitStatus, OutputWriter};
 use crate::printer::Printer;
 use crate::settings::ResolverSettings;
 
@@ -23,6 +24,7 @@ pub(crate) async fn export(
     format: ExportFormat,
     package: Option<PackageName>,
     hashes: bool,
+    output_file: Option<PathBuf>,
     extras: ExtrasSpecification,
     dev: bool,
     locked: bool,
@@ -34,6 +36,7 @@ pub(crate) async fn export(
     connectivity: Connectivity,
     concurrency: Concurrency,
     native_tls: bool,
+    quiet: bool,
     cache: &Cache,
     printer: Printer,
 ) -> Result<ExitStatus> {
@@ -110,6 +113,9 @@ pub(crate) async fn export(
         vec![]
     };
 
+    // Write the resolved dependencies to the output channel.
+    let mut writer = OutputWriter::new(!quiet || output_file.is_none(), output_file.as_deref());
+
     // Generate the export.
     match format {
         ExportFormat::RequirementsTxt => {
@@ -120,13 +126,16 @@ pub(crate) async fn export(
                 &dev,
                 hashes,
             )?;
-            anstream::println!(
+            writeln!(
+                writer,
                 "{}",
                 "# This file was autogenerated via `uv export`.".green()
-            );
+            )?;
-            anstream::print!("{export}");
+            write!(writer, "{export}")?;
         }
     }
 
+    writer.commit().await?;
+
     Ok(ExitStatus::Success)
 }

crates/uv/src/lib.rs

@@ -1323,6 +1323,7 @@ async fn run_project(
                 args.format,
                 args.package,
                 args.hashes,
+                args.output_file,
                 args.extras,
                 args.dev,
                 args.locked,
@@ -1334,6 +1335,7 @@ async fn run_project(
                 globals.connectivity,
                 globals.concurrency,
                 globals.native_tls,
+                globals.quiet,
                 &cache,
                 printer,
             )

crates/uv/src/settings.rs

@@ -957,6 +957,7 @@ pub(crate) struct ExportSettings {
     pub(crate) extras: ExtrasSpecification,
     pub(crate) dev: bool,
     pub(crate) hashes: bool,
+    pub(crate) output_file: Option<PathBuf>,
     pub(crate) locked: bool,
     pub(crate) frozen: bool,
     pub(crate) python: Option<String>,
@@ -978,6 +979,7 @@ impl ExportSettings {
             no_dev,
             hashes,
             no_hashes,
+            output_file,
             locked,
             frozen,
             resolver,
@@ -995,6 +997,7 @@ impl ExportSettings {
             ),
             dev: flag(dev, no_dev).unwrap_or(true),
             hashes: flag(hashes, no_hashes).unwrap_or(true),
+            output_file,
             locked,
             frozen,
             python,

crates/uv/tests/export.rs

@@ -636,3 +636,62 @@ fn no_hashes() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn output_file() -> Result<()> {
+    let context = TestContext::new("3.12");
+
+    let pyproject_toml = context.temp_dir.child("pyproject.toml");
+    pyproject_toml.write_str(
+        r#"
+        [project]
+        name = "project"
+        version = "0.1.0"
+        requires-python = ">=3.12"
+        dependencies = ["anyio==3.7.0"]
+
+        [build-system]
+        requires = ["setuptools>=42"]
+        build-backend = "setuptools.build_meta"
+        "#,
+    )?;
+
+    context.lock().assert().success();
+
+    uv_snapshot!(context.filters(), context.export().arg("--output-file").arg("requirements.txt"), @r###"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    # This file was autogenerated via `uv export`.
+    -e .
+    anyio==3.7.0 \
+        --hash=sha256:275d9973793619a5374e1c89a4f4ad3f4b0a5510a2b5b939444bee8f4c4d37ce \
+        --hash=sha256:eddca883c4175f14df8aedce21054bfca3adb70ffe76a9f607aef9d7fa2ea7f0
+    idna==3.6 \
+        --hash=sha256:9ecdbbd083b06798ae1e86adcbfe8ab1479cf864e4ee30fe4e46a003d12491ca \
+        --hash=sha256:c05567e9c24a6b9faaa835c4821bad0590fbb9d5779e7caa6e1cc4978e7eb24f
+    sniffio==1.3.1 \
+        --hash=sha256:f4324edc670a0f49750a81b895f35c3adb843cca46f0530f79fc1babb23789dc \
+        --hash=sha256:2f6da418d1f1e0fddd844478f41680e794e6051915791a034ff65e5f100525a2
+
+    ----- stderr -----
+    Resolved 4 packages in [TIME]
+    "###);
+
+    let contents = fs_err::read_to_string(context.temp_dir.child("requirements.txt"))?;
+    insta::assert_snapshot!(contents, @r###"
+    # This file was autogenerated via `uv export`.
+    -e .
+    anyio==3.7.0 \
+        --hash=sha256:275d9973793619a5374e1c89a4f4ad3f4b0a5510a2b5b939444bee8f4c4d37ce \
+        --hash=sha256:eddca883c4175f14df8aedce21054bfca3adb70ffe76a9f607aef9d7fa2ea7f0
+    idna==3.6 \
+        --hash=sha256:9ecdbbd083b06798ae1e86adcbfe8ab1479cf864e4ee30fe4e46a003d12491ca \
+        --hash=sha256:c05567e9c24a6b9faaa835c4821bad0590fbb9d5779e7caa6e1cc4978e7eb24f
+    sniffio==1.3.1 \
+        --hash=sha256:f4324edc670a0f49750a81b895f35c3adb843cca46f0530f79fc1babb23789dc \
+        --hash=sha256:2f6da418d1f1e0fddd844478f41680e794e6051915791a034ff65e5f100525a2
+    "###);
+
+    Ok(())
+}

docs/reference/cli.md

@@ -1873,6 +1873,8 @@ uv export [OPTIONS]
 
 <p>When disabled, uv will only use locally cached data and locally available files.</p>
 
+</dd><dt><code>--output-file</code>, <code>-o</code> <i>output-file</i></dt><dd><p>Write the compiled requirements to the given <code>requirements.txt</code> file</p>
+
 </dd><dt><code>--package</code> <i>package</i></dt><dd><p>Export the dependencies for a specific package in the workspace.</p>
 
 <p>If the workspace member does not exist, uv will exit with an error.</p>