Category Archives: sysadmin

Fixing the ruby ‘CoreFoundation/CFString.h’ file not found install error

I hit this error installing the latest Ruby using rbenv:

$ rbenv install 2.6.3
ruby-build: use openssl from homebrew
Downloading ruby-2.6.3.tar.bz2...
Installing ruby-2.6.3...
ruby-build: use readline from homebrew

BUILD FAILED (OS X 10.14.4 using ruby-build 20190423)

Inspect or clean up the working tree at /var/folders/r7/kjzbwmx533b20hcf1_s9kc9c0000gn/T/ruby-build.20190501131413.33977
Results logged to /var/folders/r7/kjzbwmx533b20hcf1_s9kc9c0000gn/T/ruby-build.20190501131413.33977.log

Last 10 log lines:
compiling error.c
compiling eval.c
compiling file.c
compiling gc.c
file.c:23:10: fatal error: 'CoreFoundation/CFString.h' file not found
1 error generated.
make: *** [file.o] Error 1
make: *** Waiting for unfinished jobs....

The problem is missing headers. To re-install just run this command:

open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg

Now, Ruby should install just fine:

$ rbenv install 2.6.3
ruby-build: use openssl from homebrew
Downloading ruby-2.6.3.tar.bz2…
Installing ruby-2.6.3…
ruby-build: use readline from homebrew
Installed ruby-2.6.3 to /Users/will/.rbenv/versions/2.6.3

Converting all files to tab indentation from spaces

Tabs are clearly the one true indentation style, but when you create a new Ruby on Rails project it uses spaces, which could lead to a mish-mash of tabs and spaces in your project, not good!

The solution? Convert them using this one simple trick from the root of the project:

for i in `find app -name *.rb`; do echo $i; cat $i | unexpand -t2 > $i.converted; mv $i.converted $i; done

Repeat as necessary for other directories (test, config etc.) and other file types (erb).

Testing http over socket connections with socat

Sometimes I need to test an http server that is listening on a unix socket. It’s really easy to do this using socat, but the socat man page is pretty long. Here it is for anyone who needs it in the future, and me when I inevitably forget.

In this case the server is unicorn, but this will work for any http server listening on a socket, for instance thin. The lines beginning with “–>” are lines I typed (the 4 lines at the start), remove the “–>” when you try this.

$ socat - UNIX-CONNECT:/u/apps/app/shared/sockets/unicorn.sock,crnl
-->GET /session/new HTTP/1.1
-->X-Forwarded-Proto: https
HTTP/1.1 200 OK
Date: Fri, 02 Dec 2011 14:37:23 GMT
Status: 200 OK
Connection: close
Strict-Transport-Security: max-age=31536000
Content-Type: text/html; charset=utf-8
X-UA-Compatible: IE=Edge,chrome=1
ETag: "2346c47c7cb3bc37729e42fc8b20c821"
Cache-Control: max-age=0, private, must-revalidate
Set-Cookie: _x_session=blablabla; path=/; HttpOnly; secure
X-Request-Id: c0a374f460d1b1205df450ab77dd2328
X-Runtime: 0.159219

<!DOCTYPE html>
<html lang="en" data-behavior="wallpaper">

For those interested in the relevance of the crnl option at the end of the socket path, this from the man page:

Converts the default line termination character NL (‘n’, 0x0a)
to/from CRNL (“rn”, 0x0d0a) when writing/reading on this
channel (example). Note: socat simply strips all CR characters.


Rewriting URL params in nginx

I came across this problem recently, a customer was moving to Ruby on Rails from another framework/language (.NET I think) and needed to re-write a bunch of URLs. Some needed the query parameters rewriting too. One example was rewriting the old search path, so the old URL:

would become:

This should be fairly simple except for the qry parameter needed to be changed to query. A bit of googling didn’t turn up much but with some experimentation I came up with this using the pre-populated nginx $args variable:

location /OldSearchPath.aspx {
  if ($args ~* qry=(.+)) {
    set $args query=$1;
rewrite ^.+$ /search redirect;

It even leaves the other parameters intact, so the pagination will still work.

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