file: improve diff output

[terceiro]

diff This makes the output of a changed file look like this:

INFO : file[/path/to/file] modified will change from 'false' to 'true'
INFO : diff:
INFO : --- /path/to/file (BEFORE)
INFO : +++ /path/to/file (AFTER)
INFO : @@ -1,2 +1,2 @@
INFO : -line 0
INFO : line 1
INFO : +line 2

That's a lot better than displaying a random temporary filename as the
second file.

[unasuke]

 INFO :       diff:
DEBUG :       Executing `diff -u --label\=/tmp/http_request_headers.html\ \(BEFORE\) /dev/null --label\=/tmp/http_request_headers.html\ \(AFTER\) /tmp/itamae_tmp/1609226585.4889503/itamae20201229-1116-q23exp`...
DEBUG :         [:post, "/v1.16/containers/8a8cf2b295fe647d87947fc017161fc4e1b2d75aab1856a8ea27e38c23e3cc44/exec", {}, "{\"User\":null,\"AttachStdin\":false,\"AttachStdout\":true,\"AttachStderr\":true,\"Tty\":false,\"Cmd\":[\"/bin/sh\",\"-c\",\"diff -u --label\\\\=/tmp/http_request_headers.html\\\\ \\\\(BEFORE\\\\) /dev/null --label\\\\=/tmp/http_request_headers.html\\\\ \\\\(AFTER\\\\) /tmp/itamae_tmp/1609226585.4889503/itamae20201229-1116-q23exp\"]}"]
DEBUG :         [:post, "/v1.16/exec/79aed478e6cafa39be49f337c867cc03cb1ec045c75bdb5558780f242a912bd2/start", {}, "{\"Tty\":false,\"Detach\":false}"]
DEBUG :         [:get, "/v1.16/exec/79aed478e6cafa39be49f337c867cc03cb1ec045c75bdb5558780f242a912bd2/json", {}, nil]
DEBUG :         exited with 1
 INFO :       --- /tmp/http_request_headers.html (BEFORE)
 INFO :       +++ /tmp/http_request_headers.html (AFTER)
 INFO :       @@ -0,0 +1,12 @@
 INFO :       +{
 INFO :       +  "args": {},
 INFO :       +  "headers": {
 INFO :       +    "Accept": "*/*",
 INFO :       +    "Accept-Encoding": "gzip;q=1.0,deflate;q=0.6,identity;q=0.3",
 INFO :       +    "Host": "httpbin.org",
 INFO :       +    "User-Agent": "Itamae",
 INFO :       +    "X-Amzn-Trace-Id": "Root=1-5fead958-248552aa65b288073c116324"
 INFO :       +  },
 INFO :       +  "origin": "118.240.233.119",
 INFO :       +  "url": "https://httpbin.org/get"
 INFO :       +}
DEBUG :       (in action_get)

before	after

[unasuke]

LGTM!

[unasuke]

Released as v1.11.1