mirror of
https://github.com/jaygooby/ttfb.sh
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185 lines
6.6 KiB
Markdown
185 lines
6.6 KiB
Markdown
# Introduction
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Measures [time-to-first-byte](https://en.wikipedia.org/wiki/Time_to_first_byte) for single or multiple URLs. Can show you quickest, slowest & median TTFB values plus optionally log all response headers.
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[](https://app.travis-ci.com/jaygooby/ttfb.sh)
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```
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Usage: ttfb [options] url [url...]
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-d debug
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-l <log file> (infers -d) log response headers. Defaults to ./curl.log
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-n <number> of times to test time to first byte
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-v verbose output. Show response breakdown (DNS lookup, TLS handshake etc)
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```
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Implicitly follows a redirection chain using curl's `-L` option.
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Can log all response headers (the default log file is `./curl.log`) by calling with `-d`.
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Override the default log file by specifying `-l /some/file`.
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Get quickest, slowest and median TTFB values by specifying the number of times to call a URL; use `-n2` for 2 tests, `-n5` for 5 and so on.
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Uses the calculation `%{time_starttransfer¹} - %{time_appconnect²}` which doesn't include any connection overhead, to better approximate [devtool’s TTFB figure](https://developers.google.com/web/tools/chrome-devtools/network/understanding-resource-timing#slow_time_to_first_byte).
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¹ [`time_starttransfer`](https://github.com/curl/curl/blob/e431daf013ea04cb1a988a2009d820224ef5fb79/docs/cmdline-opts/write-out.d#L141-L144)
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> The time, in seconds, it took from the start until the first byte was just about to be transferred. This includes time_pretransfer and also the time the server needed to calculate the result.</blockquote>
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² [`time_appconnect`](https://github.com/curl/curl/blob/e431daf013ea04cb1a988a2009d820224ef5fb79/docs/cmdline-opts/write-out.d#L118-L120)
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>The time, in seconds, it took from the start until the SSL/SSH/etc
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connect/handshake to the remote host was completed.
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# Genesis
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Based on a [gist](https://gist.github.com/sandeepraju/1f5fbdbdd89551ba7925abe2645f92b5)
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by https://github.com/sandeepraju
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Modified by jay@gooby.org, [@jaygooby](https://twitter.com/jaygooby)
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# Usage
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```
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Usage: ttfb [options] url [url...]
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-d debug
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-l <log file> (infers -d) log response headers. Defaults to ./curl.log
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-n <number> of times to test time to first byte
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-o <option> pass options to curl (e.g. -o "-k" will make curl ignore invalid certificates)
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-v verbose output. Show response breakdown (DNS lookup, TLS handshake etc)
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```
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## Examples
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Basic usage:
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```
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$ ttfb example.com
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.227436
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```
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Basic usage with verbose response breakdown:
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```
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$ ttfb -v https://example.com
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DNS lookup: 0.005152 TLS handshake: 0.000000 TTFB including connection: 0.200831 TTFB: .200831 Total time: 0.201132
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```
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Test multiple times:
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```
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$ ttfb -n 5 example.com/example/url
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.....
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fastest .177263 slowest .214302 median .179957
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```
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Test multiple URLs:
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```
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$ ttfb bbc.co.uk news.bbc.co.uk
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bbc.co.uk .049985
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news.bbc.co.uk .054122
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```
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Test multiple URLs, multiple times:
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```
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$ ttfb -n 5 bbc.co.uk news.bbc.co.uk
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.....
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.....
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bbc.co.uk fastest .030936 slowest .057755 median .034663
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news.bbc.co.uk fastest .031413 slowest .182791 median .035001
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```
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Verbose response breakdown when multiple tests specified:
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```
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$ ttfb -v -n 5 bbc.co.uk
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DNS lookup: 0.005335 TLS handshake: 0.102314 TTFB including connection: 0.148328 TTFB: .046014 Total time: 0.646115
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DNS lookup: 0.005322 TLS handshake: 0.102609 TTFB including connection: 0.150693 TTFB: .048084 Total time: 0.644611
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DNS lookup: 0.004277 TLS handshake: 0.102066 TTFB including connection: 0.172199 TTFB: .070133 Total time: 1.196256
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DNS lookup: 0.004444 TLS handshake: 0.107375 TTFB including connection: 0.160771 TTFB: .053396 Total time: 0.637290
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DNS lookup: 0.005352 TLS handshake: 0.118882 TTFB including connection: 0.168772 TTFB: .049890 Total time: 0.653761
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fastest .046014 slowest .070133 median .049890
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```
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Log all the response headers for multiple tests to multiple URLs:
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```
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ttfb -d -n 2 bbc.co.uk https://www.bbc.co.uk/weather
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..
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..
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bbc.co.uk fastest .027550 slowest .055215 median .041382
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https://www.bbc.co.uk/weather fastest .101020 slowest .297923 median .199471
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$ ls *.log
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bbc_co_uk-curl.log https___www_bbc_co_uk_weather-curl.log
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$ cat https___www_bbc_co_uk_weather-curl.log
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HTTP/2 200
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server: openresty
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x-cache-action: MISS
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vary: Accept-Encoding,X-BBC-Edge-Cache,X-BBC-Edge-Scheme,X-CDN
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x-cache-age: 0
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cache-control: private, stale-while-revalidate=10, max-age=0, must-revalidate
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content-type: text/html;charset=utf-8
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x-mrid: w1
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date: Thu, 11 Apr 2019 17:08:07 GMT
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x-xss-protection: 1; mode=block
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x-content-type-options: nosniff
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x-lb-nocache: true
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x-msig: 24e37f81323984e4e45b8048f9e3c94a
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x-frame-options: SAMEORIGIN
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content-length: 1077454
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HTTP/2 200
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server: openresty
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x-cache-action: MISS
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vary: Accept-Encoding,X-BBC-Edge-Cache,X-BBC-Edge-Scheme,X-CDN
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x-cache-age: 0
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cache-control: private, stale-while-revalidate=10, max-age=0, must-revalidate
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content-type: text/html;charset=utf-8
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x-mrid: w1
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date: Thu, 11 Apr 2019 17:08:08 GMT
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x-xss-protection: 1; mode=block
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x-content-type-options: nosniff
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x-lb-nocache: true
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x-msig: 24e37f81323984e4e45b8048f9e3c94a
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x-frame-options: SAMEORIGIN
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content-length: 1077454
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```
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# More detail on time-to-first-byte
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See https://blog.cloudflare.com/a-question-of-timing/
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and https://curl.haxx.se/docs/manpage.html for an explanation
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of how the curl variables relate to the various stages of
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the transfer.
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To get a better approximation of devtool's TTFB, we consider
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the time without the connection overhead:
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`%{time_starttransfer} - %{time_appconnect}`
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Uses a dirty `eval` to do the ttfb arithmetic. Depends
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on `bc` and `column` commands.
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# Testing
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If you'd like to submit a [PR](https://github.com/jaygooby/ttfb.sh/pulls), please add a test in the [test suite](https://github.com/jaygooby/ttfb.sh/blob/master/tests/tests.bats).
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To run the tests, call `make` from the project root. You'll need to have [bats-core](https://github.com/bats-core/bats-core) installed and in your `$PATH`.
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If you only want to run a test or two, uncomment the `# skip` lines, so they read `skip` and then those tests will be skipped.
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# TODO
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* [x] Show progress when more than one request (`-n 2` etc) option is set
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* [x] Allow custom options to be passed to curl (use the `-o` option)
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* [ ] Sort output by fastest TTFB when multiple URLs are supplied
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* [ ] Colour code the `TTFB:` figure in the standard response, according to the speed of the response.
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