diff --git a/compos/src/compilation.rs b/compos/src/compilation.rs
index ae4a29d..6049991 100644
--- a/compos/src/compilation.rs
+++ b/compos/src/compilation.rs
@@ -22,12 +22,9 @@
 use std::collections::HashMap;
 use std::env;
 use std::ffi::OsString;
-use std::fs::read_dir;
 use std::path::{self, Path, PathBuf};
 use std::process::Command;
 
-use crate::artifact_signer::ArtifactSigner;
-use crate::signing_key::DiceSigner;
 use authfs_aidl_interface::aidl::com::android::virt::fs::{
     AuthFsConfig::{
         AuthFsConfig, InputDirFdAnnotation::InputDirFdAnnotation,
@@ -105,12 +102,15 @@
     system_properties::read_bool(name, false).unwrap_or(false)
 }
 
-pub fn odrefresh(
+pub fn odrefresh<F>(
     odrefresh_path: &Path,
     context: OdrefreshContext,
     authfs_service: Strong<dyn IAuthFsService>,
-    signer: DiceSigner,
-) -> Result<ExitCode> {
+    success_fn: F,
+) -> Result<ExitCode>
+where
+    F: FnOnce(PathBuf) -> Result<()>,
+{
     // Mount authfs (via authfs_service). The authfs instance unmounts once the `authfs` variable
     // is out of scope.
     let authfs_config = AuthFsConfig {
@@ -183,13 +183,8 @@
     info!("odrefresh exited with {:?}", exit_code);
 
     if exit_code == ExitCode::CompilationSuccess {
-        // authfs only shows us the files we created, so it's ok to just sign everything under
-        // the target directory.
         let target_dir = art_apex_data.join(context.target_dir_name);
-        let mut artifact_signer = ArtifactSigner::new(&target_dir);
-        add_artifacts(&target_dir, &mut artifact_signer)?;
-
-        artifact_signer.write_info_and_signature(signer, &target_dir.join("compos.info"))?;
+        success_fn(target_dir)?;
     }
 
     Ok(exit_code)
@@ -245,24 +240,6 @@
     Ok(())
 }
 
-fn add_artifacts(target_dir: &Path, artifact_signer: &mut ArtifactSigner) -> Result<()> {
-    for entry in
-        read_dir(&target_dir).with_context(|| format!("Traversing {}", target_dir.display()))?
-    {
-        let entry = entry?;
-        let file_type = entry.file_type()?;
-        if file_type.is_dir() {
-            add_artifacts(&entry.path(), artifact_signer)?;
-        } else if file_type.is_file() {
-            artifact_signer.add_artifact(&entry.path())?;
-        } else {
-            // authfs shouldn't create anything else, but just in case
-            bail!("Unexpected file type in artifacts: {:?}", entry);
-        }
-    }
-    Ok(())
-}
-
 fn spawn_jailed_task(executable: &Path, args: &[String], env_vars: &[String]) -> Result<Minijail> {
     // TODO(b/185175567): Run in a more restricted sandbox.
     let jail = Minijail::new()?;
diff --git a/compos/src/compsvc.rs b/compos/src/compsvc.rs
index 3ec15dd..5f3ee62 100644
--- a/compos/src/compsvc.rs
+++ b/compos/src/compsvc.rs
@@ -18,17 +18,19 @@
 //! file descriptors backed by authfs (via authfs_service) and pass the file descriptors to the
 //! actual compiler.
 
-use anyhow::{Context, Result};
+use anyhow::{bail, Context, Result};
 use binder_common::new_binder_exception;
 use compos_common::binder::to_binder_result;
 use log::warn;
 use std::default::Default;
-use std::path::PathBuf;
+use std::fs::read_dir;
+use std::path::{Path, PathBuf};
 use std::sync::RwLock;
 
+use crate::artifact_signer::ArtifactSigner;
 use crate::compilation::{odrefresh, OdrefreshContext};
 use crate::dice::Dice;
-use crate::signing_key::{DiceSigner, DiceSigningKey};
+use crate::signing_key::DiceSigningKey;
 use authfs_aidl_interface::aidl::com::android::virt::fs::IAuthFsService::IAuthFsService;
 use compos_aidl_interface::aidl::com::android::compos::{
     CompOsKeyData::CompOsKeyData,
@@ -57,17 +59,6 @@
     key_blob: RwLock<Vec<u8>>,
 }
 
-impl CompOsService {
-    fn new_signer(&self) -> BinderResult<DiceSigner> {
-        let key = &*self.key_blob.read().unwrap();
-        if key.is_empty() {
-            Err(new_binder_exception(ExceptionCode::ILLEGAL_STATE, "Key is not initialized"))
-        } else {
-            to_binder_result(self.signing_key.new_signer(key))
-        }
-    }
-}
-
 impl Interface for CompOsService {}
 
 impl ICompOsService for CompOsService {
@@ -91,6 +82,14 @@
         zygote_arch: &str,
         system_server_compiler_filter: &str,
     ) -> BinderResult<i8> {
+        let key = &*self.key_blob.read().unwrap();
+        if key.is_empty() {
+            return Err(new_binder_exception(
+                ExceptionCode::ILLEGAL_STATE,
+                "Key is not initialized",
+            ));
+        }
+
         let context = to_binder_result(OdrefreshContext::new(
             compilation_mode,
             system_dir_fd,
@@ -103,8 +102,16 @@
 
         let authfs_service = get_authfs_service()?;
         let exit_code = to_binder_result(
-            odrefresh(&self.odrefresh_path, context, authfs_service, self.new_signer()?)
-                .context("odrefresh failed"),
+            odrefresh(&self.odrefresh_path, context, authfs_service, |output_dir| {
+                // authfs only shows us the files we created, so it's ok to just sign everything
+                // under the output directory.
+                let mut artifact_signer = ArtifactSigner::new(&output_dir);
+                add_artifacts(&output_dir, &mut artifact_signer)?;
+
+                let signer = to_binder_result(self.signing_key.new_signer(key))?;
+                artifact_signer.write_info_and_signature(signer, &output_dir.join("compos.info"))
+            })
+            .context("odrefresh failed"),
         )?;
         Ok(exit_code as i8)
     }
@@ -126,3 +133,21 @@
 fn get_authfs_service() -> BinderResult<Strong<dyn IAuthFsService>> {
     Ok(authfs_aidl_interface::binder::get_interface(AUTHFS_SERVICE_NAME)?)
 }
+
+fn add_artifacts(target_dir: &Path, artifact_signer: &mut ArtifactSigner) -> Result<()> {
+    for entry in
+        read_dir(&target_dir).with_context(|| format!("Traversing {}", target_dir.display()))?
+    {
+        let entry = entry?;
+        let file_type = entry.file_type()?;
+        if file_type.is_dir() {
+            add_artifacts(&entry.path(), artifact_signer)?;
+        } else if file_type.is_file() {
+            artifact_signer.add_artifact(&entry.path())?;
+        } else {
+            // authfs shouldn't create anything else, but just in case
+            bail!("Unexpected file type in artifacts: {:?}", entry);
+        }
+    }
+    Ok(())
+}