ceph-csi/docs/coding.md

# Coding Conventions

Please follow coding conventions and guidelines described in the following documents:

* [Go proverbs](https://go-proverbs.github.io/) - highly recommended read
* [CodeReviewComments](https://github.com/golang/go/wiki/CodeReviewComments)
* [Effective Go](https://golang.org/doc/effective_go.html)
* [How to Write a Git Commit Message](https://chris.beams.io/posts/git-commit/)

Here's a list of some more specific conventions that are often followed in
the code and will be pointed out in the review process:

## General

* Keep variable names short for variables that are local to the function.
* Do not export a function or variable name outside the package until you
  have an external consumer for it.

### Imports

We use the following convention for specifying imports:

```
<import standard library packages>

<import ceph-csi packages>

<import third-party packages>
```

Example:

```go
import (
 "os"
 "path"
 "strings"
 "time"

 "github.com/ceph/ceph-csi/internal/util"

 "github.com/pborman/uuid"
)
```

### Error Handling

* Use variable name `err` to denote error variable during a function call.
* Reuse the previously declared `err` variable as long as it is in scope.
  For example, do not use `errWrite` or `errRead`.
* Do not panic() for errors that can be bubbled up back to user. Use panic()
  only for fatal errors which shouldn't occur.
* Do not ignore errors using `_` variable unless you know what you're doing.
* Error strings should not start with a capital letter.
* If error requires passing of extra information, you can define a new type
* Error types should end with `Error`.

### Logging

* The inner-most utility functions should never log. Logging must almost always
  be done by the caller on receiving an `error`.
* Always use log level `DEBUG` to provide useful **diagnostic information** to
  developers or sysadmins.
* Use log level `INFO` to provide information to users or sysadmins. This is the
  kind of information you'd like to log in an out-of-the-box configuration in
  happy scenario.
* Use log level `WARN` when something fails but there's a workaround or fallback
  or retry for it and/or is fully recoverable.
* Use log level `ERROR` when something occurs which is fatal to the operation,
  but not to the service or application.