Add flag --make-parents (#4)

.github/codecov.yaml

@@ -0,0 +1,9 @@
+github_checks:
+  annotations: false
+coverage:
+  status:
+    project: off
+    patch: off
+# Fix path of Nix sandbox
+fixes:
+   - "/build/source::"

README.md

@@ -62,7 +62,8 @@ Options:
   -i, --input <FILE>       If no input file is given, read from stdin.
   -o, --output <FILE>      If no output file is given, write to stdout.
   -p, --pattern <PATTERN>  Regex pattern to replace. Must at least provide a named group 'id'. By default matches ${id}. [default: \$\{(?P<id>[^\$\{\}/]+)\}]
-  -c, --copy-if-no-creds   Copy input to output if $CREDENTIALS_DIRECTORY is not set
+  -c, --copy-if-no-creds   Copy input to output if $CREDENTIALS_DIRECTORY is not set.
+  -m, --make-parents       Make parent directories of the output file as needed.
   -h, --help               Print help
   -V, --version            Print version
 ```

nixos/tests/nixos-test-systemd-credsubst.nix

@@ -48,9 +48,10 @@ nixosTest {
         };
       };
 
-      specialisation."passthru".configuration = {
+      specialisation."passthru-parents".configuration = {
         systemd.services.systemd-credsubst-test.serviceConfig = {
-          ExecStartPre = lib.mkForce [ "${systemd-credsubst}/bin/systemd-credsubst -c -i ${appsettings} -o appsettings.json" ];
+          ExecStart = lib.mkForce "${pkgsStatic.busybox}/bin/tail -f -n +1 some/dir/appsettings.json";
+          ExecStartPre = lib.mkForce [ "${systemd-credsubst}/bin/systemd-credsubst -c -i ${appsettings} -m -o some/dir/appsettings.json" ];
           LoadCredential = lib.mkForce [ ];
         };
       };
@@ -64,10 +65,10 @@ nixosTest {
       out = machine.succeed("cat /run/systemd-credsubst-test/workdir/appsettings.json")
       assert out == '{"license":"prometheus","name":"Wurzelpfropf Banking"}', f"appsettings.json has unexpected content '{out}'"
 
-    with subtest("passthru works"):
-      machine.succeed("${nodes.machine.system.build.toplevel}/specialisation/passthru/bin/switch-to-configuration test")
+    with subtest("passthru and make parents works"):
+      machine.succeed("${nodes.machine.system.build.toplevel}/specialisation/passthru-parents/bin/switch-to-configuration test")
       machine.wait_for_unit("systemd-credsubst-test.service");
-      out = machine.succeed("cat /run/systemd-credsubst-test/workdir/appsettings.json")
+      out = machine.succeed("cat /run/systemd-credsubst-test/workdir/some/dir/appsettings.json")
       assert out == '{"license":"''${license}","name":"Wurzelpfropf Banking"}', f"appsettings.json has unexpected content '{out}'"
   '';
 }

src/main.rs

@@ -41,9 +41,15 @@ struct Cli {
     #[arg(
         short,
         long,
-        help = "Copy input to output if $CREDENTIALS_DIRECTORY is not set"
+        help = "Copy input to output if $CREDENTIALS_DIRECTORY is not set."
     )]
     copy_if_no_creds: bool,
+    #[arg(
+        short,
+        long,
+        help = "Make parent directories of the output file as needed."
+    )]
+    make_parents: bool,
 }
 
 fn validate_path_exists(path: &str) -> Result<PathBuf, String> {
@@ -95,10 +101,17 @@ fn input_reader(input: Option<&PathBuf>) -> Result<Box<dyn Read>> {
     Ok(reader)
 }
 
-fn output_writer(output: Option<&PathBuf>) -> Result<Box<dyn Write>> {
+fn output_writer(output: Option<&PathBuf>, make_parents: bool) -> Result<Box<dyn Write>> {
     let writer: Box<dyn Write> = match output {
         None => Box::new(io::stdout()) as Box<dyn Write>,
         Some(filename) => {
+            if make_parents {
+                let parent_dir = &filename.parent().unwrap_or(Path::new("/"));
+                fs::create_dir_all(parent_dir).context(format!(
+                    "Failed to create parent directories of '{}'",
+                    filename.display()
+                ))?;
+            }
             let f = File::create(filename).context(format!(
                 "Failed to open '{}' for writing",
                 filename.display()
@@ -109,9 +122,9 @@ fn output_writer(output: Option<&PathBuf>) -> Result<Box<dyn Write>> {
     Ok(writer)
 }
 
-fn passthru(input: Option<&PathBuf>, output: Option<&PathBuf>) -> Result<()> {
+fn passthru(input: Option<&PathBuf>, output: Option<&PathBuf>, make_parents: bool) -> Result<()> {
     let mut reader = input_reader(input)?;
-    let mut writer = output_writer(output)?;
+    let mut writer = output_writer(output, make_parents)?;
 
     io::copy(&mut reader, &mut writer)?;
 
@@ -141,6 +154,7 @@ fn substitute(
     output: Option<&PathBuf>,
     creds_dir: &str,
     pattern: &Regex,
+    make_parents: bool,
 ) -> Result<()> {
     // Read input as string
     let mut reader = input_reader(input)?;
@@ -174,7 +188,7 @@ fn substitute(
     )?;
 
     // Write the modified contents
-    let mut writer = output_writer(output)?;
+    let mut writer = output_writer(output, make_parents)?;
     writer.write_all(modified.as_bytes())?;
 
     Ok(())
@@ -197,10 +211,11 @@ fn main() -> Result<ExitCode> {
             cli.output.as_ref(),
             &creds_dir?,
             &cli.pattern,
+            cli.make_parents,
         )?,
         Err(err) => {
             if cli.copy_if_no_creds {
-                passthru(cli.input.as_ref(), cli.output.as_ref())?;
+                passthru(cli.input.as_ref(), cli.output.as_ref(), cli.make_parents)?;
             } else {
                 return Err(err);
             }

tests/credsubst.rs

@@ -249,3 +249,61 @@ fn copy_if_no_creds() -> Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn make_parents() -> Result<()> {
+    let credentials_dir = tempfile::tempdir()?;
+    let mut file = File::create(credentials_dir.path().join("yaxi-license"))?;
+    file.write_all(b"hunter1\n\n")?;
+
+    let out_dir = tempfile::tempdir()?;
+    let output_filename = out_dir.path().join("wur/zel/pfropf");
+
+    Command::cargo_bin(crate_name!())?
+        .env("CREDENTIALS_DIRECTORY", credentials_dir.path())
+        .arg("--output")
+        .arg(&output_filename)
+        .arg("--make-parents")
+        .write_stdin(indoc! {r#"
+            {
+                "wurzel": "pfropf",
+                "license": "${yaxi-license}",
+                "wuff": "c://msdog",
+                "password": "secret-password:${/with-special-chars}"
+            }
+        "#})
+        .assert();
+
+    assert_eq!(
+        std::fs::read_to_string(output_filename)?,
+        indoc! {r#"
+            {
+                "wurzel": "pfropf",
+                "license": "hunter1",
+                "wuff": "c://msdog",
+                "password": "secret-password:${/with-special-chars}"
+            }
+        "#}
+    );
+
+    Ok(())
+}
+
+#[test]
+fn fails_no_make_parents() -> Result<()> {
+    Command::cargo_bin(crate_name!())?
+        .arg("--output")
+        .arg("/does/not/exist")
+        .arg("--copy-if-no-creds")
+        .write_stdin("wurzelpfropf")
+        .assert()
+        .stdout("")
+        .stderr(indoc! {r#"
+            Error: Failed to open '/does/not/exist' for writing
+
+            Caused by:
+                No such file or directory (os error 2)
+        "#});
+
+    Ok(())
+}