Allow stdin/stdout for --tar (closes #12)

CHANGELOG.md

@@ -4,6 +4,8 @@ This project follows [semantic versioning](http://semver.org).
 
 
 ### UNRELEASED
+* [added] Ability to read/write tar file from/to stdin/stdout
+* [modified] Logging to stderr
 * [fixed] Only print "repairing bundles" if actually repairing bundles
 
 

docs/man/zvault-backup.1.md

@@ -29,6 +29,8 @@ The patterns can be given directly via `--exclude` or be read from a file via
 exclude pattern is read from the file `excludes` in the repository folder.
 All exclude pattern given via any of these ways will be combined.
 
+If `--tar` is specified and `SRC` is `-`, the input is read from stdin.
+
 Unless `--xdev` is set, zVault will not traverse into subfolders that are on a
 different filesystem, i.e. mount points will not be included.
 

docs/man/zvault-restore.1.md

@@ -16,7 +16,7 @@ The backup or backup subtree given by `BACKUP` must be in the format
 If `repository` is omitted, the default repository location is used instead.
 
 If `--tar` is set, the data is written to a tar file named `DST`. In this case
-`DST` must not exist.
+`DST` must not exist. If `DST` is `-`, the data will be written to stdout.
 
 If `--tar` is not set, the data will be written into the existing folder `DST`.
 

src/cli/logger.rs

@@ -2,8 +2,16 @@ use log::{self, LogRecord, LogLevel, LogMetadata};
 pub use log::SetLoggerError;
 
 use ansi_term::{Color, Style};
+use std::io::Write;
 
 
+macro_rules! println_stderr(
+    ($($arg:tt)*) => { {
+        let r = writeln!(&mut ::std::io::stderr(), $($arg)*);
+        r.expect("failed printing to stderr");
+    } }
+);
+
 struct Logger(LogLevel);
 
 impl log::Log for Logger {
@@ -14,11 +22,11 @@ impl log::Log for Logger {
     fn log(&self, record: &LogRecord) {
         if self.enabled(record.metadata()) {
             match record.level() {
-                LogLevel::Error => println!("{}: {}", Color::Red.bold().paint("error"), record.args()),
-                LogLevel::Warn => println!("{}: {}", Color::Yellow.bold().paint("warning"), record.args()),
-                LogLevel::Info => println!("{}: {}", Color::Green.bold().paint("info"), record.args()),
-                LogLevel::Debug => println!("{}: {}", Style::new().bold().paint("debug"), record.args()),
-                LogLevel::Trace => println!("{}: {}", "trace", record.args())
+                LogLevel::Error => println_stderr!("{}: {}", Color::Red.bold().paint("error"), record.args()),
+                LogLevel::Warn => println_stderr!("{}: {}", Color::Yellow.bold().paint("warning"), record.args()),
+                LogLevel::Info => println_stderr!("{}: {}", Color::Green.bold().paint("info"), record.args()),
+                LogLevel::Debug => println_stderr!("{}: {}", Style::new().bold().paint("debug"), record.args()),
+                LogLevel::Trace => println_stderr!("{}: {}", "trace", record.args())
             }
         }
     }

src/repository/tarfile.rs

@@ -2,7 +2,7 @@ use ::prelude::*;
 
 use std::collections::{HashMap, HashSet, BTreeMap};
 use std::path::{Path, PathBuf};
-use std::io::{Read, Cursor};
+use std::io::{self, Read, Write, Cursor};
 use std::fs::File;
 use std::str;
 
@@ -71,8 +71,8 @@ impl Repository {
         Ok(inode)
     }
 
-    fn import_tarfile_as_inode<P: AsRef<Path>>(&mut self, backup: &mut Backup, tarfile: P, failed_paths: &mut Vec<PathBuf>) -> Result<(Inode, ChunkList), RepositoryError> {
-        let mut tarfile = tar::Archive::new(try!(File::open(tarfile)));
+    fn import_tarfile_as_inode<R: Read>(&mut self, backup: &mut Backup, input: R, failed_paths: &mut Vec<PathBuf>) -> Result<(Inode, ChunkList), RepositoryError> {
+        let mut tarfile = tar::Archive::new(input);
         // Step 1: create inodes for all entries
         let mut inodes = HashMap::<PathBuf, (Inode, HashSet<String>)>::new();
         for entry in try!(tarfile.entries()) {
@@ -185,7 +185,12 @@ impl Repository {
         let info_before = self.info();
         let start = Local::now();
         let mut failed_paths = vec![];
-        let (root_inode, chunks) = try!(self.import_tarfile_as_inode(&mut backup, tarfile, &mut failed_paths));
+        let tarfile = tarfile.as_ref();
+        let (root_inode, chunks) = if tarfile == Path::new("-") {
+            try!(self.import_tarfile_as_inode(&mut backup, try!(File::open(tarfile)), &mut failed_paths))
+        } else {
+            try!(self.import_tarfile_as_inode(&mut backup, io::stdin(), &mut failed_paths))
+        };
         backup.root = chunks;
         try!(self.flush());
         let elapsed = Local::now().signed_duration_since(start);
@@ -208,7 +213,7 @@ impl Repository {
         }
     }
 
-    fn export_xattrs(&mut self, inode: &Inode, tarfile: &mut tar::Builder<File>) -> Result<(), RepositoryError> {
+    fn export_xattrs<W: Write>(&mut self, inode: &Inode, tarfile: &mut tar::Builder<W>) -> Result<(), RepositoryError> {
         let mut data = Vec::new();
         for (key, value) in &inode.xattrs {
             let mut len_len = 1;
@@ -231,7 +236,7 @@ impl Repository {
         Ok(try!(tarfile.append(&header, Cursor::new(&data))))
     }
 
-    fn export_tarfile_recurse(&mut self, backup: &Backup, path: &Path, inode: Inode, tarfile: &mut tar::Builder<File>) -> Result<(), RepositoryError> {
+    fn export_tarfile_recurse<W: Write>(&mut self, backup: &Backup, path: &Path, inode: Inode, tarfile: &mut tar::Builder<W>) -> Result<(), RepositoryError> {
         if !inode.xattrs.is_empty() {
             try!(self.export_xattrs(&inode, tarfile));
         }
@@ -277,9 +282,16 @@ impl Repository {
     }
 
     pub fn export_tarfile<P: AsRef<Path>>(&mut self, backup: &Backup, inode: Inode, tarfile: P) -> Result<(), RepositoryError> {
+        let tarfile = tarfile.as_ref();
+        if tarfile == Path::new("-") {
+            let mut tarfile = tar::Builder::new(io::stdout());
+            try!(self.export_tarfile_recurse(backup, Path::new(""), inode, &mut tarfile));
+            try!(tarfile.finish());
+        } else {
             let mut tarfile = tar::Builder::new(try!(File::create(tarfile)));
             try!(self.export_tarfile_recurse(backup, Path::new(""), inode, &mut tarfile));
             try!(tarfile.finish());
+        }
         Ok(())
     }