stdintap 0.1.0

CLI tool to read lines from stdin and broadcast them to connected TCP clients
stdintap-0.1.0 is not a library.

stdintap

Read lines from stdin and copy them to all connected clients.

Features

  • UNIX socket support (including Linux's abstract namespace)
  • Adjustable behaviour of handling slow clients: lines may be dropped or backpressure can be applied.
  • For slow clients, stdintap can announce number of omitted lines. Alternatively, it can announce moments where backpressure was applied.
  • History mode - stdintap can keep N last lines and replay them to connected clients. There is optional announcement where history ends and realtime data begins.
  • Optional printing of timestamps (using monotonic timer) and sequence numbers.
  • Maximum line size is limited (adjustable). You can use zero byte instead of newline if needed.
  • You can request content to be also forwarded to stdout.

Installation

Download a pre-built executable from Github releases or install from source code with cargo install --path . or cargo install stdintap.

CLI options

CLI tool to read lines from stdin and broadcast them to connected TCP clients

Usage: 

Arguments:
  <LISTEN_ADDRESS>
          Socket address to listen for incoming connections.
          
          Various types of addresses are supported:
          
          * TCP socket address and port, like 127.0.0.1:8080 or [::]:80
          
          * UNIX socket path like /tmp/mysock or Linux abstract address like @abstract
          
          * Special keyword "sd-listen" to accept connections from file descriptor 3 (e.g. systemd socket activation). You can also specify a named descriptor after a colon or * to use all passed sockets.
          
          Note that some features may be disabled by compile-time settings.

Options:
  -q, --qlen <QLEN>
          Size of broadcast channel for serving the lines
          
          [default: 16]

      --backpressure
          Slow down reading from stdin if connected clients are slow in reading output

  -x, --announce-overruns
          Inject special lines that denote missed content due to slow reading In `--backpressure` mode, it will insert announcements that backpressure is applied Additionally, stdin EOFs will also be announced.
          
          When `--timestamps` are active, special lines are separated from the timestamp by spaces instead of tabs.
          
          Note that overrun announcements may exacerbate overruns.

      --disconnect-on-overruns
          Disconnect clients when they are too slow to read lines

  -t, --timestamps
          Prefix messages with a monotone timestamps

  -H, --hello-message
          Inject initial message at the beginning of each client connection
          
          With --history option, the hello message appears after the history, before the "online" content.

      --max-line-size <MAX_LINE_SIZE>
          Automatically split lines longer than this
          
          [default: 65536]

  -0, --zero-separated
          Separata lines by zero byte instead of \n

  -T, --tee
          Also copy stdin to stdout

      --seqn
          Print sequence numbers of lines

      --history <HISTORY>
          Remember and this number of lines and replay them to each connecting client

      --require-observer
          Don't read from stdin unless at least one client is connected.
          
          Does not gurantee lack of dropped lines on disconnections.

  -h, --help
          Print help (see a summary with '-h')

  -V, --version
          Print version

(manually removed an inapplicable phrase)

      --unix-listen-unlink
          remove UNIX socket prior to binding to it

      --unix-listen-chmod <UNIX_LISTEN_CHMOD>
          change filesystem mode of the newly bound UNIX socket to `owner`, `group` or `everybody`

      --unix-listen-uid <UNIX_LISTEN_UID>
          change owner user of the newly bound UNIX socket to this numeric uid

      --unix-listen-gid <UNIX_LISTEN_GID>
          change owner group of the newly bound UNIX socket to this numeric uid

      --sd-accept-ignore-environment
          ignore environment variables like LISTEN_PID or LISTEN_FDS and unconditionally use file descritor `3` as a socket in sd-listen or sd-listen-unix modes

      --tcp-keepalive <TCP_KEEPALIVE>
          set SO_KEEPALIVE settings for each accepted TCP connection.
          
          Value is a colon-separated triplet of time_ms:count:interval_ms, each of which is optional.

      --tcp-reuse-port
          Try to set SO_REUSEPORT, so that multiple processes can accept connections from the same port in a round-robin fashion

      --recv-buffer-size <RECV_BUFFER_SIZE>
          Set socket's SO_RCVBUF value

      --send-buffer-size <SEND_BUFFER_SIZE>
          Set socket's SO_SNDBUF value

      --tcp-only-v6
          Set socket's IPV6_V6ONLY to true, to avoid receiving IPv4 connections on IPv6 socket

      --tcp-listen-backlog <TCP_LISTEN_BACKLOG>
          Maximum number of pending unaccepted connections

See also