Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/proger/erlsh
Erlang shell tools
https://github.com/proger/erlsh
Last synced: 2 months ago
JSON representation
Erlang shell tools
- Host: GitHub
- URL: https://github.com/proger/erlsh
- Owner: proger
- License: isc
- Created: 2013-08-28T08:42:31.000Z (over 11 years ago)
- Default Branch: master
- Last Pushed: 2022-04-17T14:58:10.000Z (over 2 years ago)
- Last Synced: 2024-08-02T02:14:39.388Z (5 months ago)
- Language: Erlang
- Homepage:
- Size: 13.7 KB
- Stars: 61
- Watchers: 4
- Forks: 12
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- freaking_awesome_elixir - Erlang - Family of functions and ports involving interacting with the system shell, paths and external programs. (Utilities)
- fucking-awesome-elixir - erlsh - Family of functions and ports involving interacting with the system shell, paths and external programs. (Utilities)
- awesome-elixir - erlsh - Family of functions and ports involving interacting with the system shell, paths and external programs. (Utilities)
README
## erlsh
Family of functions and ports involving interacting with the system shell, paths and external programs.
Reason why not `os:cmd/1`:
```erlang
> Email = "hacker+/somepath&reboot#@example.com". % this is a valid email!
> os:cmd(["mkdir -p ", Email]).
% path clobbering and a reboot may happen here!
```
Examples with `erlsh:run/1,2,3,4`, `erlsh:oneliner/1,2`, `erlsh_path:escape/1`:
```erlang
> erlsh:oneliner("uname -v"). % oneliner/1,2 funs do not include newlines
{done,0,
<<"Darwin Kernel Version 12.4.0: Wed May 1 17:57:12 PDT 2013; root:xnu-2050.24.15~1/RELEASE_X86_64">>}
> erlsh:oneliner("git describe --always").
{done,128,<<"fatal: Not a valid object name HEAD">>}
> erlsh:oneliner("git describe --always", "/tank/proger/vxz/otp").
{done,0,<<"OTP_R16B01">>}
> erlsh:run(["git", "clone", "https://github.com/proger/darwinkit.git"], binary, "/tmp").
{done,0,<<"Cloning into 'darwinkit'...\n">>}
> UserUrl = "https://github.com/proger/darwinkit.git".
"https://github.com/proger/darwinkit.git"
> erlsh:run(["git", "clone", UserUrl], binary, "/tmp").
{done,128,
<<"fatal: destination path 'darwinkit' already exists and is not an empty directory.\n">>}
> Path = erlsh_path:escape("email+=/[email protected]").
"email+=%[email protected]"
> erlsh:oneliner(["touch", filename:join("/tmp/", Path)]).
{done,0,<<>>}
> erlsh:run(["ifconfig"], "/tmp/output.log", "/tank/proger/vxz/otp").
{done,0,"/tmp/output.log"}
% cat /tmp/output.log
>>> {{2013,8,28},{8,39,14}} /sbin/ifconfig
lo0: flags=8049 mtu 16384
options=3
inet6 fe80::1%lo0 prefixlen 64 scopeid 0x1
inet 127.0.0.1 netmask 0xff000000
inet6 ::1 prefixlen 128
gif0: flags=8010 mtu 1280
stf0: flags=0<> mtu 1280
en0: flags=8863 mtu 1500
ether 7c:d1:c3:e9:24:65
inet6 fe80::7ed1:c3ff:fee9:2465%en0 prefixlen 64 scopeid 0x4
inet 192.168.63.163 netmask 0xfffffc00 broadcast 192.168.63.255
media: autoselect
status: active
p2p0: flags=8843 mtu 2304
ether 0e:d1:c3:e9:24:65
media: autoselect
status: inactive
>>> {{2013,8,28},{8,39,14}} exit status: 0
```
### fdlink port
Consider a case of spawning a port that does not actually read its standard input (e.g. `socat` that bridges `AF_UNIX` with `AF_INET`):
``` shell
# pstree -A -a $(pgrep make)
make run
`-sh -c...
`-beam.smp -- -root /usr/lib/erlang -progname erl -- -home /root -- -pa ebin -config run/sys.config -eval[ok = application:
|-socat tcp-listen:32133,reuseaddr,bind=127.0.0.1 unix-connect:/var/run/docker.sock
`-16*[{beam.smp}]
```
If you terminate the node, `beam` will close the port but the process will still remain alive (thus, it will leak).
To mitigate this issue, you can use `fdlink` that will track `stdin` availability for you:
``` shell
# pstree -A -a $(pgrep make)
make run
`-sh -c...
`-beam.smp -- -root /usr/lib/erlang -progname erl -- -home /root -- -pa ebin -config run/sys.config -eval[ok = application:
|-fdlink /usr/bin/socat tcp-listen:32133,reuseaddr,bind=127.0.0.1 unix-connect:/var/run/docker.sock
| `-socat tcp-listen:32133,reuseaddr,bind=127.0.0.1 unix-connect:/var/run/docker.sock
`-16*[{beam.smp}]
```
Using `fdlink` is easy:
```erlang
> Fdlink = erlsh:fdlink_executable(). % make sure your app dir is setup correctly
> Fdlink = filename:join("./priv", "fdlink"). % in case you're running directly from erlsh root
> erlang:open_port({spawn_executable, Fdlink}, [stream, exit_status, {args, ["/usr/bin/socat"|RestOfArgs]}).
```
`fdlink` will also close the standard input of its child process.