Add initial implementation

Author: breml

.gitignore

@@ -0,0 +1,27 @@
+# === Go ===
+
+# If you prefer the allow list template instead of the deny list, see community template:
+# https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
+#
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+ec_check
+
+# Test binary, built with `go test -c`
+*.test
+
+# Output of the go coverage tool, specifically when used with LiteIDE
+*.out
+
+# Dependency directories (remove the comment below to include it)
+# vendor/
+
+# Go workspace file
+go.work
+go.work.sum
+
+dist/

README.md

@@ -2,6 +2,48 @@
 
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 
+`ec_check` is a tool to check Elastic Cloud deployments.
+
+As of now, the main function is to evaluate, if downscaling of an Elasticsearch
+data tier within an Elastic Cloud deployment is possible based on the current
+disk usage.
+
+## Usage
+
+### Downscale Check
+
+By default, for downscaling, only strict vertical downscaling is proposed.
+
+By providing the extra flag `--recommend-zone-change`, `ec_check` will also
+propose a combination of changing the instance size and the number of used zones
+at the same time.  
+**CAUTION**: This mode is not recommended by Elastic. If you strictly require 3
+zones, this feature can not be used.
+
+```bash
+$ ec_check downscale --region <region> --profile <profile> --deployment <name> --username <username> --password <password>
+```
+
+By default, a headroom of 25% is required after downscaling for `ec_check` to
+propose downscaling of a data tier. This can be changed by flag: `--headroom-pct`
+and the respective percentage, e.g.: `--headroom-pct 27.5`
+
+### Elasticsearch Regions
+
+Get the supported list of regions:
+
+```bash
+$ ec_check regions
+```
+
+### Elasticsearch Profiles
+
+Get the supported list of hardware profiles for a given region:
+
+```bash
+$ ec_check profiles --region <region>
+```
+
 ## Community
 
 This project has adopted the code of conduct defined by the [Contributor Covenant](https://contributor-covenant.org/)