wait-on

The wait-on CLI utility waits for files, ports, sockets, or HTTP(S) resources to become available. It exits with code 0 when all resources are ready, or a non-zero code if interrupted or timed out. You can combine it with other commands in a shell using && to run a command only after the resources are ready.

Resource Types and Prefixes: Resources are identified by prefixes. If no prefix is provided, it is assumed to be a file.

• file:: A regular file (default). Example: file:/path/to/file
• http:: HTTP HEAD returns a 2XX response. Example: http://m.com:90/foo
• https:: HTTPS HEAD returns a 2XX response. Example: https://my/bar
• http-get:: HTTP GET returns a 2XX response. Example: http-get://m.com:90/foo
• https-get:: HTTPS GET returns a 2XX response. Example: https-get://my/bar
• tcp:: A TCP port is listening. Example: tcp:1.2.3.4:9000 or tcp:foo.com:700
• socket:: A Domain Socket is listening. Example: socket:/path/to/sock
  • Note for HTTP over socket: Use the format http://unix:SOCK_PATH:URL_PATH. Example: http://unix:/path/to/sock:http://server/foo/bar

The following options are available for the wait-on command line utility:

-c, --config

js or json config file, useful for http(s) options

-d, --delay

Initial delay before checking for resources in ms, default 0

--httpTimeout

Maximum time in ms to wait for an HTTP HEAD/GET request, default 0
  which results in using the OS default

-i, --interval

Interval to poll resources in ms, default 250ms

-l, --log

Log resources begin waited on and when complete or errored

-r, --reverse

Reverse operation, wait for resources to NOT be available

-s, --simultaneous

Simultaneous / Concurrent connections to a resource, default Infinity
  Setting this to 1 would delay new requests until previous one has completed.
  Used to limit the number of connections attempted to a resource at a time.

-t, --timeout

Maximum time in ms to wait before exiting with failure (1) code, 
  default Infinity
  Use postfix 'ms', 's', 'm' or 'h' to change the unit.

--tcpTimeout

Maximum time in ms for tcp connect, default 300ms
  Use postfix 'ms', 's', 'm' or 'h' to change the unit.

--httpTimeout

Maximum time to wait for the HTTP request, default Infinity
  Use postfix 'ms', 's', 'm' or 'h' to change the unit.

-v, --verbose

Enable debug output to stdout

-w, --window

Stability window, the time in ms defining the window of time that
  resource needs to have not changed (file size/availability) before
  signaling success, default 750ms. If less than interval, it will be
  reset to the value of interval. This is only used for files, other
  resources are considered available on first detection.

-h, --help

Show this message

The wait-on CLI supports several options to control behavior, timeouts, and polling.

-c, --config          js or json config file
-d, --delay           Initial delay before checking for resources in ms, default 0
--httpTimeout         Maximum time in ms to wait for an HTTP HEAD/GET request, default 0
-i, --interval         Interval to poll resources in ms, default 250ms
-l, --log              Log resources begin waited on and when complete or errored
-r, --reverse          Reverse operation, wait for resources to NOT be available
-s, --simultaneous     Simultaneous / Concurrent connections to a resource, default Infinity
-t, --timeout          Maximum time in ms to wait before exiting with failure (1), default Infinity
--tcpTimeout          Maximum time in ms for tcp connect, default 300ms
-v, --verbose          Enable debug output to stdout
-w, --window          Stability window, the time in ms defining the window of time that resource needs to have not changed before signalling success, default 750ms
-h, --help             Show this message

The following flags can be used to control the behavior of the wait-on CLI. Note that some flags have aliases.