Rust tar append file - rust

Question

I am trying to append file to existing tar file with using tar = "0.4.38" crate. It is appending but archive manager and crates entries() function only see the first file. I looked at with hex editor written parts is there. Can somebody write an example how to append file existing tar file? I tried same situation with exact files at exact sizes with GNU tar. In its hex dump file headers starts at 0x0, 0x400, 0x800 positions. In rust 0x000, 0x800, 0x1000. What did i wrong? Thank you.
use std::{fs::{OpenOptions, File}, io::{Write, Seek}};
use std::io::BufWriter;
use std::time;
fn add2(pid:&str) {
let dest = "../../Downloads/test.tar";
let mut f = OpenOptions::new().append(true).create(true).open(&dest).unwrap();
let mut t = tar::Builder::new(&mut f);
let mut h = tar::Header::new_gnu();
h.set_path(format!("{}.txt", pid)).unwrap();
h.set_size(9);
h.set_username("soni").unwrap();
h.set_mode(420);
let d = time::SystemTime::now().duration_since(time::UNIX_EPOCH).unwrap();
h.set_mtime(d.as_secs());
h.set_cksum();
let _k = t.append(&h, format!("{}_data", pid).as_bytes()).unwrap();
}
fn main() {
let files = vec!["4924", "4923", "4921"];
for fi in files {
add2(fi);
}
}
┌────────┬─────────────────────────┬─────────────────────────┬────────┬────────┐
│00000000│ 34 39 32 34 2e 74 78 74 ┊ 00 00 00 00 00 00 00 00 │4924.txt┊00000000│
│00000010│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00000060│ 00 00 00 00 30 30 30 30 ┊ 36 34 34 00 00 00 00 00 │00000000┊64400000│
│00000070│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 30 30 30 30 │00000000┊00000000│
│00000080│ 30 30 30 30 30 31 31 00 ┊ 31 34 33 36 36 30 31 30 │00000110┊14366010│
│00000090│ 30 37 32 00 30 30 30 36 ┊ 34 34 37 00 00 00 00 00 │07200006┊44700000│
│000000a0│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00000100│ 00 75 73 74 61 72 20 20 ┊ 00 73 6f 6e 69 00 00 00 │0ustar ┊0soni000│
│00000110│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00000200│ 34 39 32 34 5f 64 61 74 ┊ 61 00 00 00 00 00 00 00 │4924_dat┊a0000000│
│00000210│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00000800│ 34 39 32 33 2e 74 78 74 ┊ 00 00 00 00 00 00 00 00 │4923.txt┊00000000│
│00000810│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00000860│ 00 00 00 00 30 30 30 30 ┊ 36 34 34 00 00 00 00 00 │00000000┊64400000│
│00000870│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 30 30 30 30 │00000000┊00000000│
│00000880│ 30 30 30 30 30 31 31 00 ┊ 31 34 33 36 36 30 31 30 │00000110┊14366010│
│00000890│ 30 37 32 00 30 30 30 36 ┊ 34 34 36 00 00 00 00 00 │07200006┊44600000│
│000008a0│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00000900│ 00 75 73 74 61 72 20 20 ┊ 00 73 6f 6e 69 00 00 00 │0ustar ┊0soni000│
│00000910│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00000a00│ 34 39 32 33 5f 64 61 74 ┊ 61 00 00 00 00 00 00 00 │4923_dat┊a0000000│
│00000a10│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00001000│ 34 39 32 31 2e 74 78 74 ┊ 00 00 00 00 00 00 00 00 │4921.txt┊00000000│
│00001010│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00001060│ 00 00 00 00 30 30 30 30 ┊ 36 34 34 00 00 00 00 00 │00000000┊64400000│
│00001070│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 30 30 30 30 │00000000┊00000000│
│00001080│ 30 30 30 30 30 31 31 00 ┊ 31 34 33 36 36 30 31 30 │00000110┊14366010│
│00001090│ 30 37 32 00 30 30 30 36 ┊ 34 34 34 00 00 00 00 00 │07200006┊44400000│
│000010a0│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00001100│ 00 75 73 74 61 72 20 20 ┊ 00 73 6f 6e 69 00 00 00 │0ustar ┊0soni000│
│00001110│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00001200│ 34 39 32 31 5f 64 61 74 ┊ 61 00 00 00 00 00 00 00 │4921_dat┊a0000000│
│00001210│ 00 00 00 00 00 00 00 00 ┊ 00 00 00 00 00 00 00 00 │00000000┊00000000│
│* │ ┊ │ ┊ │
│00001800│ ┊ │ ┊ │
└────────┴─────────────────────────┴─────────────────────────┴────────┴────────┘
example of how to append file existing tar file with tar-rs.

Answer 1

As indicated in the docs,
Also note that after all files have been written to an archive the finish function needs to be called to finish writing the archive.
When you're done with your builder, you need to finish with it.
t.finish()
or, if you prefer to have the underlying writer back, you can use t.into_inner() to finish and give you the writer.