power_shell
===========
Advanced system-wide Erlang shell capabilities
[](https://travis-ci.com/WhatsApp/power_shell)
Build with rebar3:
rebar3 compile
Versions supported: tested with OTP-22, 21 and 20.
There is no support for older OTP versions, due to changes made for R20.
Basic eval() worked down to R16B.
Documentation can be built with edoc: `rebar3 edoc`
License
-------
power_shell license is available in the LICENSE file in the root directory of this source tree.
Usage
--------------
power_shell can be used as an application, and in form of a library. When started as application, power_shell examines
**shell_integration** configuration parameter. It can be set to shell_default, or user_default. Depending on the
parameter, power_shell can load itself as user_default module (if none was loaded before), or add proxy calls to
already loaded user_default module.
### Evaluating non-exported functions
Enter `power_shell:eval(Mod, Fun, [Arg1, Arg2, Arg3]).` in the shell to evaluate function Fun in module Mod. It does
not need to be exported.
If module Mod is currently loaded, power_shell will try to locate corresponding *.beam file, load debug info chunk and
evaluate function Fun with supplied arguments.
If module is not loaded, but *.beam file can be found, power_shell does not attempt to load it. However, if there is a
remote (fully qualified) call, Erlang VM (BEAM) will load the file automatically.
When shell integration (injection) is enabled, evaluating non-exported functions is simplified to just `eval(Mod, Fun, [Args].`
### Debugging shortcuts
Available with shell integration.
### Coverage Analysis Tool for Erlang
Modules that were patched by 'cover' application are also supported. If a module was cover_compiled, and it is being
evaluated with power_shell:eval, coverage analysis works as expected.
Configuration
-------------
During application startup, power_shell examines following application environment variables:
- **cache_code** (boolean, default false) - start code cache process. This process keeps decompiled beam files in
memory, speeding up execution if code does not change
- **shell_integration** (atom, shell_default | user_default, default is user_default) - apply shell integration,
making `power_shell:eval(Mod, Fun, Args)` available in shell, `eval(Mod, Fun, Args)`
It is possible to supply values using sys.config file, or via command line when starting BEAM:
erl -power_shell cache_code true
Features planned
----------------
- [ ] shell integration, allowing to execute non-exported functions directly from the shell, using convenient syntax:
`some_mod:non_exported(Arg1, Arg2, Arg3).` and not `eval(some_mod, non_exported, [Arg1, Arg2, Arg3]).`
- [ ] ectl library integration
- [ ] monitoring library integration
- [ ] additional shell commands for debugging & troubleshooting
