README.md

godif

Go dependency injection for functions (and not only...)

Usage Example

• Service implementation

Usage

Provide func implementation

• Declare: var toInject func()
• Register to be injected: godif.Require(&toInject)
• Provide implementation: godif.Provide(&toInject, f)
• Resolve: godif.ResolveAll()
  • Non-assignable var provided on Require() or Provide() call -> error, further validation is skipped
  • Incompatible types -> error
  • More than one implementations provided -> error
  • No implementation -> error
  • Something provided from a package but nothing is required for the package -> error (package is not used)
  • Not required -> no error, no implementation

Provide key-value

• Declare: var MyMap map[string]int
• Implement
  • Manually: MyMap = map[string]int{}
  • Provide implementation: godif.Provide(&MyMap, map[string]int{})
• Provide data: godif.ProvideKeyValue(&MyMap, "key1", 1)
• Resolve: godif.ResolveAll()
  • Non-assignable var provided or ProvideKeyValue() call -> error, further validation is skipped
  • Data provided but not implemented -> error
  • Implementation provided but no data provided -> no error, assume not required -> no implementation
  • Use godif.Provide() if implemented manually -> error
  • If implementation provided
    • Multiple implementations -> error
    • Non-map or map of incompatible key or value type -> error
  • Multiple values per key -> error
  • Key or value of different types provided -> error

Provide key-slice

• Declare: var MyMap map[string][]int
• Implement
  • Manually: MyMap = map[string][]int{}
  • Provide implementation: godif.Provide(&MyMap, map[string][]int{})
• Add initial data if needed: MyMap["key1"] = append(MyMap["key1"], 42)
  • Further godif.ProvideKeyValue() calls will append data to the existing slice
• Provide data:
  • godif.ProvideKeyValue(&MyMap, "key1", 1)
  • godif.ProvideKeyValue(&MyMap, "key1", 2)
  • godif.ProvideKeyValue(&MyMap, "key1", []int{3, 4})
• Resolve: godif.ResolveAll()
  • Non-assignable var provided on ProvideKeyValue() call -> error, further validation is skipped
  • Data provided but not implemented -> error
  • Use godif.Provide() if implemented manually -> error
  • If implementation provided
    • Multiple implementations -> error
    • Slice of incompatible element type -> error
  • Data and implementation are provided but implementation is not required -> error (target map will be nil)

Provide slice element

• Declare: var MySlice []string
• Require: Require(&MySlice)
• Implementation for slices is not neccessary but possible:
  • Manually: MySlice = []string{}
  • Provide implementation: godif.Provide(&MySlice, []string{})
• Add initial data if needed: MySlice = append(MySlice, 42)
  • Further godif.ProvideSliceElement() calls will append data to the existing slice
• Provide data:
  • godif.ProvideSliceElement(&MySlice, "str1")
  • godif.ProvideSliceElement(&MySlice, []string{"str3", "str4"})
• Resolve: godif.ResolveAll()
  • Non-assignable var provided on ProvideSliceElement() call -> error, further validation is skipped
  • Use godif.Provide() if implemented manually -> error
  • Multiple implementations -> error
  • Incompatible types -> error

Reset all injections

• godif.Reset()
• Provided and required vars will be nilled
• Provided not required vars with data provided by ProvideKeyValue() or ProvideSciceElement() (assume required) will be nilled
• Manually inited vars will be kept
• Data injected into manually inited vars will be kept