feat: expand tilde notation in configuration file

Backup roots and log file can now say ~/foo/bar to refer to files
relative to the user's home directory.

4 files changed, 64 insertions, 8 deletions

diff --git a/obnam.md b/obnam.md
index e788d96..3050463 100644
--- a/obnam.md
+++ b/obnam.md
@@ -1122,6 +1122,29 @@ encrypt: false
 ~~~
 
 
+## Client expands tildes in its configuration file
+
+This scenario verifies that the client expands tildes in pathnames in
+its configuration file.
+
+
+~~~scenario
+given an installed obnam
+and file tilde.yaml
+when I run obnam --config tilde.yaml config
+then stdout contains home directory followed by /important
+then stdout contains home directory followed by /obnam.log
+~~~
+
+~~~{#tilde.yaml .file .yaml .numberLines}
+roots: [~/important]
+log: ~/obnam.log
+server_url: https://backup.example.com
+verify_tls_cert: true
+encrypt: false
+~~~
+
+
 ## Client requires https
 
 This scenario verifies that the client rejects a configuration with a
diff --git a/src/config.rs b/src/config.rs
index 6881959..b30cfa3 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -91,21 +91,26 @@ impl ClientConfigWithoutPasswords {
         trace!("read_config: filename={:?}", filename);
         let config = std::fs::read_to_string(filename)?;
         let tentative: TentativeClientConfig = serde_yaml::from_str(&config)?;
-
+        let roots = tentative
+            .roots
+            .iter()
+            .map(|path| expand_tilde(path))
+            .collect();
+        let log = tentative
+            .log
+            .map(|path| expand_tilde(&path))
+            .unwrap_or_else(|| PathBuf::from(DEVNULL));
         let encrypt = tentative.encrypt.or(Some(false)).unwrap();
         let exclude_cache_tag_directories = tentative.exclude_cache_tag_directories.unwrap_or(true);
 
         let config = Self {
+            chunk_size: tentative.chunk_size.or(Some(DEFAULT_CHUNK_SIZE)).unwrap(),
+            encrypt,
             filename: filename.to_path_buf(),
+            roots,
             server_url: tentative.server_url,
-            roots: tentative.roots,
             verify_tls_cert: tentative.verify_tls_cert.or(Some(false)).unwrap(),
-            chunk_size: tentative.chunk_size.or(Some(DEFAULT_CHUNK_SIZE)).unwrap(),
-            log: tentative
-                .log
-                .or_else(|| Some(PathBuf::from(DEVNULL)))
-                .unwrap(),
-            encrypt,
+            log,
             exclude_cache_tag_directories,
         };
 
@@ -126,3 +131,19 @@ impl ClientConfigWithoutPasswords {
         Ok(())
     }
 }
+
+fn expand_tilde(path: &Path) -> PathBuf {
+    if path.starts_with("~/") {
+        if let Some(home) = std::env::var_os("HOME") {
+            let mut expanded = PathBuf::from(home);
+            for comp in path.components().skip(1) {
+                expanded.push(comp);
+            }
+            expanded
+        } else {
+            path.to_path_buf()
+        }
+    } else {
+        path.to_path_buf()
+    }
+}
diff --git a/subplot/client.py b/subplot/client.py
index 1ddc772..be0a6d6 100644
--- a/subplot/client.py
+++ b/subplot/client.py
@@ -102,3 +102,12 @@ def stdout_matches_file(ctx, filename=None):
     stdout = runcmd_get_stdout(ctx)
     data = open(filename).read()
     assert_eq(stdout, data)
+
+
+def stdout_contains_home_dir_path(ctx, path=None):
+    runcmd_get_stdout = globals()["runcmd_get_stdout"]
+    stdout = runcmd_get_stdout(ctx)
+    wanted = os.path.abspath(os.path.normpath("./" + path))
+    logging.debug(f"stdout_contains_home_dir_path: stdout={stdout!r}")
+    logging.debug(f"stdout_contains_home_dir_path: wanted={wanted!r}")
+    assert wanted in stdout
diff --git a/subplot/client.yaml b/subplot/client.yaml
index 8c76e9f..6de04c9 100644
--- a/subplot/client.yaml
+++ b/subplot/client.yaml
@@ -28,3 +28,6 @@
 
 - then: "stdout matches file {filename}"
   function: stdout_matches_file
+
+- then: "stdout contains home directory followed by {path}"
+  function: stdout_contains_home_dir_path