Waits for expected HTTP response

waitehr (wait [for] expected HTTP response) is a CLI program that waits for HTTP response and retries request until the expected response is received.

Motivation

We needed a reliable utility for checking when a deployment goes live in a CI/CD pipeline.

Why not just use Bash/curl/...?

You should be able to do this with curl and a simple bash script.

You could achieve something similar to this with bash:

while curl https://gajus.com/ | grep -q Gajus; do sleep 1; done

However, by the time you add:

• routine timeout
• request timeout
• follow redirects
• max redirects
• success threshold

It is going to be a pretty hefty script, and if everyone (with their varying experience of using Bash) were to write that script adhoc, it is likely to be error prone. It is for this reason that it makes sense to use a well tested utility that does it well.

Install

npm install waitehr --global

Usage

waitehr <url> [options]

# Waits for response with status code 200.
waitehr https://gajus.com/

# Retries request at most once every 5 seconds (default: 1).
waitehr https://gajus.com/ --interval 5

# Waits at most 120 seconds (default: 60).
waitehr https://gajus.com/ --timeout 60

# Waits for response with status code 200 or 404.
waitehr https://gajus.com/ --status-code 200 404

# Waits for response that contains "foo" and "bar".
waitehr https://gajus.com/ --contains "foo" "bar"

# Waits for response that has a specific header.
waitehr https://gajus.com/ --has-header "foo: bar"

# Adds custom headers to the request.
waitehr https://gajus.com/ --header "Accepts: text/html" "Authorization: Bearer
fkd9afsda9k"


Options:
  --help               Show help                                       [boolean]
  --version            Show version number                             [boolean]
  --contains           Expected string(s). If multiple strings are provided,
                       then all of them must be contained in the response.
                                                                         [array]
  --follow-redirect    Defines if redirect responses should be followed
                       automatically.                                  [boolean]
  --has-header         Expected header(s). If multiple headers are provided,
                       then all of them must be contained in the response.
                                                                         [array]
  --header             Extra header to include in the request when sending HTTP
                       to a server. <Header Key>: <Header Value>.        [array]
  --initial-delay      How many seconds to delay the first request.
                                                           [number] [default: 0]
  --interval           How many seconds to sleep between every attempt.
                                                           [number] [default: 1]
  --max-redirects      If exceeded, the request will be aborted.
                                                           [number] [default: 5]
  --prepend-time       Prepends time to each check output.
                                                       [boolean] [default: true]
  --quiet              Disables any output.           [boolean] [default: false]
  --request-timeout    How many seconds to wait for individual requests to
                       complete. If exceeded, requests are aborted and a new
                       request is started.                 [number] [default: 5]
  --status-codes       Expected status code(s). If multiple status codes are
                       provided, then either will be accepted as valid.
                                                        [array] [default: "200"]
  --success-threshold  Minimum consecutive successes for the probe to be
                       considered successful.              [number] [default: 1]
  --timeout            How many seconds to wait before giving up.  [default: 60]

Alternatives

• check_http – Nagios plugin with equivalent functionality.
• httping – utility for measuring latency and throughput of a webserver with limited some assertion capabilities.