dnf - 如何顯示選擇了哪個鏡像 url？

下面是 bash 日誌的一部分，完整的日誌可以在https://gist.github.com/limkokhole/f2a423112aa005f10862獲得：

[xiaobai@xiaobai hello]$ dnf --verbose download --source readline
cachedir: /var/cache/dnf
Loaded plugins: noroot, needs-restarting, reposync, copr, playground, kickstart, Query, generate_completion_cache, builddep, download, config-manager, protected_packages, system-upgrade, debuginfo-install
DNF version: 0.6.4
repo: using cache for: spot-chromium
not found deltainfo for: Copr repo for chromium owned by spot
not found updateinfo for: Copr repo for chromium owned by spot
repo: using cache for: rpmfusion-nonfree-updates-testing
not found deltainfo for: RPM Fusion for Fedora 21 - Nonfree - Test Updates
not found updateinfo for: RPM Fusion for Fedora 21 - Nonfree - Test Updates
repo: using cache for: updates-source
...
not found deltainfo for: RPM Fusion for Fedora 21 - Nonfree - Updates Source
not found updateinfo for: RPM Fusion for Fedora 21 - Nonfree - Updates Source
readline-6.3-5.fc21.src.rpm                                                                                                             623 kB/s | 2.4 MB     00:03    
[xiaobai@xiaobai hello]$ 

我也試過dnf info了，網址http://cnswww.cns.cwru.edu/php/chet/readline/rltop.html不是回購網址：

[xiaobai@xiaobai hello]$ dnf info readline
[sudo] password for xiaobai: 
Using metadata from Thu Dec 31 19:18:09 2015 (6:13:33 hours old)
Installed Packages
Name        : readline
Arch        : i686
Epoch       : 0
Version     : 6.3
Release     : 5.fc21
Size        : 446 k
Repo        : @System
Summary     : A library for editing typed command lines
URL         : http://cnswww.cns.cwru.edu/php/chet/readline/rltop.html
License     : GPLv3+
Description : The Readline library provides a set of functions that allow users to
           : edit command lines. Both Emacs and vi editing modes are available. The
           : Readline library includes additional functions for maintaining a list
           : of previously-entered command lines for recalling or editing those
           : lines, and for performing csh-like history expansion on previous
           : commands.

Name        : readline
Arch        : x86_64
Epoch       : 0
Version     : 6.3
Release     : 5.fc21
Size        : 483 k
Repo        : @System
Summary     : A library for editing typed command lines
URL         : http://cnswww.cns.cwru.edu/php/chet/readline/rltop.html
License     : GPLv3+
Description : The Readline library provides a set of functions that allow users to
           : edit command lines. Both Emacs and vi editing modes are available. The
           : Readline library includes additional functions for maintaining a list
           : of previously-entered command lines for recalling or editing those
           : lines, and for performing csh-like history expansion on previous
           : commands.

[xiaobai@xiaobai hello]$ 

我怎麼知道選擇了哪個 url 或域來下載這個 readline-6.3-5.fc21.src.rpm ？--verbose似乎沒有顯示連結。退出 bash 會話後，將來如何從 dnf 歷史記錄中獲取此 url 資訊？

感謝@muru 指出負責下載的 librepo。

目前的解決方法是定義 adebug_function並將其傳遞給set_debug_log_handler（請參閱download_packages.py） in repo.py：

def download_payloads(payloads, drpm):
   # download packages
   drpm.err.clear()
   targets = [pload.librepo_target() for pload in payloads]
   errs = _DownloadErrors()
   try:

       #START my custom code
       def debug_function(msg, _):
           print("##hole## msg:", msg)
       librepo.set_debug_log_handler(debug_function)
       #END my custom  code

       librepo.download_packages(targets, failfast=True)
   except librepo.LibrepoException as e:
       errs.fatal = e.args[1] or '<unspecified librepo error>'
   ...

該repo.py文件可以手動定位：

[xiaobai@xiaobai log]$ python -c 'import sys, dnf.repo; print(sys.modules["dnf.repo"])'
<module 'dnf.repo' from '/usr/lib/python2.7/site-packages/dnf/repo.py'>
[xiaobai@xiaobai log]$ 

**$$ UPDATE $$**在 Fedora 24 中，路徑是/usr/lib/python3.5/site-packages/dnf/repo.py.

現在我可以獲得網址http://ftp.jaist.ac.jp/pub/Linux/Fedora/releases/21/Everything/source/SRPMS/r/readline-6.3-5.fc21.src。轉：

[xiaobai@xiaobai test]$ dnf download --source readline
[sudo] password for xiaobai: 
Using metadata from Thu Dec 31 19:18:09 2015 (1 day, 11:59:10 hours old)
...
##hole## msg: select_next_target: Selecting mirror for: r/readline-6.3-5.fc21.src.rpm
##hole## msg: select_suitable_mirror: Skipping rsync url: rsync://ftp.jaist.ac.jp/pub/Linux/Fedora/releases/21/Everything/source/SRPMS/
##hole## msg: prepare_next_transfer: URL: http://ftp.jaist.ac.jp/pub/Linux/Fedora/releases/21/Everything/source/SRPMS/r/readline-6.3-5.fc21.src.rpm
##hole## msg: prepare_next_transfer: Resume ignored, existing file was not originaly being downloaded by Librepo
##hole## msg: lr_download: Downloading started
##hole## msg: lr_headercb: Server returned Content-Length: "2493152" (converted 2493152/2493152 expected)                             ] ---  B/s |   0  B     --:-- ETA
##hole## msg: check_transfer_statuses: Transfer finished: r/readline-6.3-5.fc21.src.rpm (Effective url: http://ftp.jaist.ac.jp/pub/Linux/Fedora/releases/21/Everything/source/SRPMS/r/readline-6.3-5.fc21.src.rpm)
##hole## msg: check_finished_trasfer_checksum: Checksum (sha256) 521bd47a3293e694190a237921a9954b20fa41d0e8e38183d186452d4cc62ac8 is OK
readline-6.3-5.fc21.src.rpm                                                                                                             1.4 MB/s | 2.4 MB     00:01    
##hole## msg: lr_download_packages: Restoring an old SIGINT handler
[xiaobai@xiaobai test]$ 

當然，如果 dnf 記錄此 url 以供將來參考，從 commanddnf history或 file檢索可能會更好/var/log/dnf.log。

就dnf其本身而言，這是一個延遲的功能請求。顯然dnf不知道網址。見評論 4 和 5：

抱歉，我/我們誤解了動機。僅供參考，DNF 實際上不知道 URL。它只知道“metalink”的 URL 和包的文件名（和一些其他元數據）。底層庫 librepo 負責選擇最佳鏡像、編寫 URL 和下載文件。順便說一句，這意味著我們需要在庫中進行一些回調以向您提供資訊。僅供參考…

---

問題是我們不知道 metalinks 的 URL，它由 librepo 在較低級別處理。如果有人共享相同的案例並希望看到此功能，請發表評論，您將有更高的機會擁有此功能。

引用自：https://unix.stackexchange.com/questions/252538