Project Patterns

References: [Examples](examples.md)

Functional Options

[Example](examples.md#functional-options)

Use With* functions for configurable constructors:

func NewClient(baseURL string, options ...ClientOption) *Client {
    opts := defaultOptions()
    for _, option := range options {
        option(opts)
    }
    // create client...
}

client := NewClient(url, WithTimeout(30*time.Second), WithRetryCount(3))

Must Pattern

[Example](examples.md#must-pattern)

Allowed only in cmd/, internal/apps/ - to fail fast on misconfiguration.

func Must[T any](f func() (T, error)) T {
    v, err := f()
    if err != nil { panic(err) }
    return v
}

Caching Decorator

[Example](examples.md#caching-decorator)

Wrap clients with cache layer for transparent caching.

Error Handling

[Example](examples.md#error-handling)

Configuration

[Example](examples.md#configuration)

Rules: No ARNs in app config, no secrets in files, use time.Duration with custom unmarshaler

HTTP Client with Retry

[Example](examples.md#http-client)

client := tracing.NewRestyClient(baseURL,
    tracing.WithTimeout(30*time.Second),
    tracing.WithRetryCount(3),
    tracing.WithExponentialBackoff(true),
)

DynamoDB Key Design

[Example](examples.md#dynamodb)

Use composite keys (PK + SK), GSIs for query patterns.

Feature Flags

[Example](examples.md#feature-flags)

Fallback defaults, check at service layer, log evaluations.

JSON Tags

[Example](examples.md#json-tags)

Use camelCase for JSON tags and query params.

Request Validation

[Example](examples.md#validation)

Use ozzo-validation for struct validation.

Libraries