Improve CLI args/output

 - Don't require the output path to have .apk on the end
 - Print a clearer warning about random keys
 - Use stderr for warnings, not stdout
 - Print the locations of files written to disk
 - Print a "finished" message instead of remaining silent

Author: adamsoutar

README.md

@@ -27,14 +27,17 @@ JAR Signing and the APK Signature Scheme v2 and v3.
 
 <details>
   <summary><h3>...as a CLI</h3></summary>
+
 pack can be used in place of `aapt2` etc. on desktop machines. After cloning the
 repo:
 
 ```sh
-$ cargo run -p pack-cli ./watchface watchface.apk
-# Will generate both watchface.apk and watchface.aab.
-# Both will be signed using a built-in testing key/certificate.
+$ cargo run -p pack-cli ./watchface ./package
+# Will generate both package.apk and package.aab.
+# Both will be signed using a random testing key/certificate.
+# For custom signing, pass a .pem file as a third CLI argument.
 ```
+
 </details>
 
 <details>

pack-asset-compiler/src/xml_file.rs

@@ -329,7 +329,8 @@ pub fn xml_to_res_chunk<T: Read + Seek>(
             }
             Ok(XmlEvent::EndDocument) => {}
             Err(e) => return Err(PackError::XmlParsingFailed(e)),
-            _ => println!("Warning: Unknown XML part: {:?}", event.unwrap())
+            // TODO: Don't println from within this library crate, consumers might not want that
+            _ => eprintln!("Warning: Unknown XML part: {:?}", event.unwrap())
         }
     }
 

pack-cli/src/main.rs

@@ -24,7 +24,7 @@ pub mod res_dir;
 /// ```
 /// $ ls ./watchface
 /// res/ AndroidManifest.xml
-/// $ pack-cli ./watchface ./watchface/package.apk
+/// $ pack-cli ./watchface ./watchface/package
 /// $ ls ./watchface
 /// res/ AndroidManifest.xml package.apk package.aab
 /// ```
@@ -41,10 +41,11 @@ fn main() -> Result<()> {
     let in_dir = env::args()
         .nth(1)
         .ok_or(PackError::Cli("Input directory path not provided".into()))?;
-    let out_apk_path = env::args()
+    let out_path = env::args()
         .nth(2)
         .ok_or(PackError::Cli("Output APK path not provided".into()))?;
-    let out_aab_path = PathBuf::from(&out_apk_path).with_extension("aab");
+    let out_apk_path = PathBuf::from(&out_path).with_extension("apk");
+    let out_aab_path = PathBuf::from(&out_path).with_extension("aab");
 
     let signing_keys =
         env::args()
@@ -72,9 +73,13 @@ fn main() -> Result<()> {
     };
 
     let apk = compile_and_sign_apk(&pkg, &signing_keys)?;
-    fs::write(out_apk_path, apk)?;
+    fs::write(&out_apk_path, apk)?;
+    println!("Wrote {:?} to disk", out_apk_path);
     let aab = compile_and_sign_aab(&pkg, &signing_keys)?;
-    fs::write(out_aab_path, aab)?;
+    fs::write(&out_aab_path, aab)?;
+    println!("Wrote {:?} to disk", out_aab_path);
+
+    println!("Compiled, aligned & signed successfully!");
 
     Ok(())
 }

pack-cli/src/res_dir.rs

@@ -28,7 +28,7 @@ pub fn read_res_dir(res_path: &PathBuf) -> Result<Vec<FileResource>> {
                 }
             }
         }
-        println!("Warning: Ignoring unusable res/ entry {:?}", res_type)
+        eprintln!("Warning: Ignoring unusable res/ entry {:?}", res_type)
     }
     Ok(resources)
 }
@@ -37,7 +37,7 @@ fn collect_resources(path: &PathBuf, resources: &mut Vec<FileResource>) {
     let res_name = path.file_name().unwrap().to_string_lossy();
     let maybe_resource_files = fs::read_dir(path);
     if let Err(err) = maybe_resource_files {
-        println!(
+        eprintln!(
             "Warning: Failed to read res/ subdirectory {} {:?}",
             res_name, err
         );
@@ -63,7 +63,7 @@ fn collect_resources(path: &PathBuf, resources: &mut Vec<FileResource>) {
                 }
             }
         }
-        println!(
+        eprintln!(
             "Warning: Ignoring unusable {} resource entry {:?}",
             res_name, file
         )

pack-sign/src/crypto_keys.rs

@@ -96,7 +96,8 @@ impl Keys {
         use rcgen::{CertificateParams, DistinguishedName, DnType, KeyPair};
         use rsa::pkcs8::{EncodePrivateKey, LineEnding};
 
-        println!("Warning: Randomly generating a placeholder signing key. This is slow!");
+        eprintln!("Warning: Randomly generating a placeholder signing key. This is slow!");
+        eprintln!("    It's recommended to generate your own keys first and pass them in.");
 
         // Randomly generate an RSA Private Key, derive its Public Key,
         // and prepare it for passing over to the rcgen library.