Conditions in Finit are dependencies: if A is asserted, service B is
allowed to run. When A goes through FLUX (e.g., upstream reloads),
dependents are PAUSED and then simply resumed when the condition is
reasserted -- this is the correct behavior for barrier-style deps
like <pid/syslogd>.
However, some setups have tightly coupled services where dependents
must be reloaded/restarted when an upstream service reloads, not just
resumed. E.g., the FRR routing stack on Infix OS:
netd <pid/mgmtd> ← zebra <!pid/netd> ← {staticd,ripd} <!pid/zebra>
When netd reloads (SIGHUP), zebra and its dependents must be restarted
to pick up the new configuration.
The new '~' condition prefix marks a dependency as flux-sensitive:
service <!~pid/netd> name:zebra ...
When the upstream condition goes FLUX and returns to ON, the dependent
is reloaded (SIGHUP) or restarted (noreload '!') instead of merely
resumed. Transitivity follows naturally through the condition chain.
Closes#416Closes#476
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
Similar to systemd's RemainAfterExit=yes. Prevents the task from
re-running on runlevel re-entry and ensures the post: script runs
when explicitly stopped or when leaving valid runlevels.
Useful for tasks that set up persistent state like firewall rules:
task [2345] remain:yes \
post:/usr/sbin/teardown-firewall \
/usr/sbin/setup-firewall -- Firewall setup
Not supported for bootstrap-only tasks (runlevel S only) since these
are deleted immediately after completion.
Implement supplementary group support for services, allowing them to
access resources owned by multiple groups. Uses the @user:group,sup1,sup2
syntax to explicitly specify supplementary groups, in addition to now
reading group membership from /etc/group.
The PTY approach caused isatty() to return true for services using
the log directive, triggering programs like fprintd (using glib) to
emit ANSI escape codes and other TTY-specific formatting in syslog.
Using a standard pipe ensures isatty() correctly returns false, so
programs produce plain text output suitable for logging.
For services that require line-buffered output, users can wrap the
command with `stdbuf -oL` as documented in doc/config/logging.md.
Fixes#455
Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
Implement Linux capability support for services, allowing them to run
with minimal required privileges instead of running as root. This uses
the modern IAB (Inheritable, Ambient, Bounding) API from libcap.
Ollie Gutierrez