Improve lockfiles #1193

adriendelsalle · 2021-09-30T14:51:03Z

Description

Handle files and directories locks
- LockFile now takes the path to lock instead of the name of the supposed lock file
  - this allows to disambiguate a file path between the lock file or the file to be locked
  - an optional timeout argument can be specified to the constructorn defaulting to Context::lock_timeout value
Handle multiple locks acquired on the same path
- from the same process -> raise a std::logic_error
- from the another process: try lock in a blocking way and raise a std::runtime_error is a timeout is set
  - on Windows, implement a timeout calling _locking with _LK_LOCK every seconds
    - which is similar to _LK_NBLOCK but with control over the timeout
    - allows infinite loops as on Unix systems
  - on Unix, call fcntl with F_SETLKW in a separate thread and cancel it if timeout is met
  - we could change the default behavior to avoid infinite loops later (setting the timeout to some large number)
Improve logs
Add tests
- add another testing CMake target mamba_test_lock to have a CLI for testing is_locked and lock paths for subprocesses
- check creation of one or multiple locks on the same path from both current and foreign processes
Add micromamba CLI options/flags
- -l,--locks to micromamba clean to remove lock files in caches
- --lock-timeout to set the lock file timeout

src/core/util.cpp

handle multiple locks acquired from the same process improve logs add tests refactor use of LockFile forbid locking twice same path from same PID improve windows lockfile to match unix one split Lock and LockFile use byte 21 to set lock status enable reading locked file on windows ensure closing of file descriptor in Lock and LockFile destructors add timeout implementation for unix add testing lock cli for subprocess tests add subprocess tests add --lock-timeout to umamba add clean lock files add a clean lock files flag -l,--locks to umamba clean command add cpp-filesystem pins to enforce correct version on dev mode

src/core/util.cpp

use it to ensure consistency of lock position improve logs add comment in code implement custom timeout on Windows

wolfv · 2021-10-06T16:57:38Z

test/testing/lock.cpp

@@ -27,7 +27,7 @@ is_locked(const fs::path& path)
    // From another process than the lockfile one, we can open/close
    // a new file descriptor without risk to clear locks
    int fd = open(path.c_str(), O_RDWR | O_CREAT, 0666);
-    bool is_locked = mamba::LockFile::is_locked(fd);
+    bool is_locked = mamba::Lock::is_locked(fd);


I would like to keep the LockFile name -- because that's what it is. A "Lock" is a bit ambigous.

remove tests failing in non writable caches

refactor names

wolfv reviewed Sep 30, 2021

View reviewed changes