public-inbox-daemon(8)

PUBLIC-INBOX-DAEMON(8)

public-inbox user manual

PUBLIC-INBOX-DAEMON(8)

NAME

public-inbox-daemon - common usage for public-inbox network daemons

SYNOPSIS

        public-inbox-netd
        public-inbox-httpd
        public-inbox-imapd
        public-inbox-nntpd
        public-inbox-pop3d

DESCRIPTION

This manual describes common options and behavior for public-inbox network daemons. Network daemons for public-inbox provide read-only IMAP, HTTP, NNTP and POP3 access to public-inboxes. Write access to a public-inbox will never be required to run these.

These daemons are implemented with a common core using non-blocking sockets and optimized for fairness; even with thousands of connected clients over slow links.

They also provide graceful shutdown/upgrade support to avoid breaking existing connections during software upgrades.

These daemons may also utilize multiple pre-forked worker processes to take advantage of multiple CPUs.

OPTIONS

-l [PROTOCOL://]ADDRESS[?opt1=val1,opt2=val2]

--listen [PROTOCOL://]ADDRESS[?opt1=val1,opt2=val2]

This takes an absolute path to a Unix socket or HOST:PORT to listen on. For example, to listen to TCP connections on port 119, use: "-l 0.0.0.0:119". This may also point to a Unix socket ("-l /path/to/http.sock") for a reverse proxy like nginx(8) to use.

May be specified multiple times to allow listening on multiple sockets.

Unless per-listener options are used (required for public-inbox-netd(1)), this does not need to be specified at all if relying on systemd.socket(5) or similar,

Per-listener options may be specified after "?" as "KEY=VALUE" pairs delimited by ",". See public-inbox-netd(1) for documentation on the "backlog=", "cert=", "key=", "env.NAME=VALUE", "out=", "err=", "psgi=", "servername=", and "serverport=" options available.

Default: server-dependent unless socket activation is used with systemd(1) or similar (see systemd.socket(5)).

-1

--stdout PATH

Specify an appendable path to redirect stdout descriptor (1) to. Using this is preferable to setting up the redirect externally (e.g. >>/path/to/log in shell) since it allows SIGUSR1 to be handled (see "SIGNALS" in SIGNALS below).

"out=" may also be specified on a per-listener basis.

Default: /dev/null with "--daemonize", inherited otherwise

-2 PATH

--stderr PATH

Like "--stdout", but for the stderr descriptor (2).

"err=" may also be specified on a per-listener basis.

Default: /dev/null with "--daemonize", inherited otherwise

-W INTEGER

--worker-processes INTEGER

Set the number of worker processes.

Normally, this should match the number of CPUs on the system to take full advantage of the hardware. However, users of memory-constrained systems may want to lower this.

Setting this to zero ("-W0") disables the master/worker split; saving some memory but removing the ability to use SIGTTIN to increase worker processes or have the worker restarted by the master on crashes.

Default: 1

-X INTEGER

--xapian-helpers INTEGER

Enables the use of Xapian helper processes to handle expensive, non-deterministic Xapian search queries asynchronously without blocking simple requests.

With positive values, there is an additional manager process that can be signaled to control the number of Xapian helper workers.

* "-X0" one worker, no manager process * "-X1" one worker, one manager process ... * "-X8" eight workers, one manager process

As with the public-facing public-inbox-* daemons, sending "SIGTTIN" or "SIGTTOU" to the Xapian helper manager process will increment or decrement the number of workers.

Both Xapian helper workers and managers automatically respawn if they crash or are explicitly killed, even with "-X0".

A C++ compiler, pkg-config(1), and Xapian development files (e.g. "libxapian-dev" or "xapian*-core-dev*") are required to gain access to some expensive queries and significant memory savings.

Xapian helper workers are shared by all "--worker-processes" of the Perl daemon for additional memory savings.

New in public-inbox 2.0.0.

Default: undefined, search queries are handled synchronously

--cert /path/to/cert

The default TLS certificate for HTTPS, IMAPS, NNTPS, POP3S and/or STARTTLS support if the "cert" option is not given with "--listen".

With this option, well-known TCP ports automatically get TLS or STARTTLS support if using systemd-compatible socket activation. That is, ports 443, 563, 993, and 995 support HTTPS, NNTPS, IMAPS, and POP3S, respectively; while ports 110, 119, and 143 support STARTTLS on POP3, NNTP, and IMAP, respectively.

--key /path/to/key

The default TLS certificate key for the default "--cert" or per-listener "cert=" option. The private key may be concatenated into the cert file itself, in which case this option is not needed.

--multi-accept INTEGER

By default, each worker accepts one connection at a time to maximize fairness and minimize contention across multiple processes on a shared listen socket. Accepting multiple connections at once may be useful in constrained deployments with few, heavily loaded workers. Negative values enables a worker to accept all available clients at once, possibly starving others in the process. -1 behaves like "multi_accept yes" in nginx; while 0 (the default) is "multi_accept no" in nginx. Positive values allow fine-tuning without the runaway behavior of -1.

This may be specified on a per-listener basis via the "multi-accept=" per-listener directive (e.g. "-l http://127.0.0.1?multi-accept=1").

Default: 0

SIGNALS

Most of our signal handling behavior is copied from nginx(8) and/or starman(1), so it is possible to reuse common scripts for managing them.

SIGUSR1: Reopens log files pointed to by --stdout and --stderr options.
SIGUSR2: Spawn a new process with the intention to replace the running one. See "UPGRADING" below.
SIGHUP: Reload config files associated with the process. (Note: broken for public-inbox-httpd(1) only in <= 1.6)
SIGTTIN: Increase the number of running worker processes by one.
SIGTTOU: Decrease the number of running worker processes by one.
SIGWINCH: Stop all running worker processes. SIGHUP or SIGTTIN may be used to restart workers.
SIGQUIT: Gracefully terminate the running process.

SIGTTOU, SIGTTIN, SIGWINCH all have no effect when worker processes are disabled with "-W0" on the command-line.

ENVIRONMENT

PI_CONFIG: The default config file, normally "~/.public-inbox/config". See public-inbox-config(5)
LISTEN_FDS, LISTEN_PID: Used by systemd (and compatible) installations for socket activation. See systemd.socket(5) and sd_listen_fds(3).
PERL_INLINE_DIRECTORY: Pointing this to a writable directory enables the use of Inline and Inline::C extensions which may provide platform-specific performance improvements. Currently, this enables the use of vfork(2) which speeds up subprocess spawning with the Linux kernel.
public-inbox will never enable Inline::C automatically without this environment variable set or "~/.cache/public-inbox/inline-c" created by a user. See Inline and Inline::C for more details.

UPGRADING

There are two ways to upgrade a running process.

Users of process management systems with socket activation (systemd(1) or similar) may rely on multiple daemon instances. For systemd, this means using two (or more) '@' instances for each service (e.g. "SERVICENAME@INSTANCE") as documented in systemd.unit(5).

Users of traditional SysV init may use SIGUSR2 to spawn a replacement process and gracefully terminate the old process using SIGQUIT.

In either case, the old process will not truncate running responses; so responses to expensive requests do not get interrupted and lost.

CONTACT

Feedback welcome via plain-text mail to <mailto:meta@public-inbox.org>

The mail archives are hosted at <https://public-inbox.org/meta/> and <http://4uok3hntl7oi7b4uf4rtfwefqeexfzil2w6kgk2jn5z2f764irre7byd.onion/meta/>

COPYRIGHT

License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>