Configuration

Driver specific configuration option and instructions can be found on their individual pages.

Configuration is done in a bobgen.yaml file in the same directory. A different configuration file can be passed with the -c or --config flag.

The configuration is marshalled in to the Config struct.

// Config for the running of the commands
type Config struct {
    // Struct tags to generate
    Tags []string `yaml:"tags"`
    // Disable generating factory for models.
    NoFactory bool `yaml:"no_factory"`
    // Disable back referencing in the loaded relationship structs
    NoBackReferencing bool `yaml:"no_back_referencing"`
    // Delete the output folder (rm -rf) before generation to ensure sanity
    Wipe bool `yaml:"wipe"`
    // Decides the casing for go structure tag names. camel, title or snake (default snake)
    StructTagCasing string `yaml:"struct_tag_casing"`
    // Relationship struct tag name
    RelationTag string `yaml:"relation_tag"`
    // List of column names that should have tags values set to '-' (ignored during parsing)
    TagIgnore []string `yaml:"tag_ignore"`

    Types         drivers.Types `yaml:"types"`         // register custom types
    Aliases       Aliases       `yaml:"aliases"`       // customize aliases
    Constraints   Constraints   `yaml:"constraints"`   // define additional constraints
    Relationships Relationships `yaml:"relationships"` // define additional relationships

    Replacements []Replace   `yaml:"replacements"`
    Inflections  Inflections `yaml:"inflections"`

    // Customize the generator name in the top level comment of generated files
    // >>   Code generated by **GENERATOR NAME**. DO NOT EDIT.
    // defaults to "BobGen [driver] [version]"
    Generator string `yaml:"generator"`
}

Name	Description	Default
tags	Struct tags to generate	[]
no_factory	Disable generation factories for models	false
no_back_referencing	If this is set to true, when relationships are loaded, the parent is not added to the loaded object's relations	false
wipe	If to delete the output folder before generation	false
struct_tag_casing	Decides the casing for go structure tag names. camel, title or snake (default snake)	"snake"
relation_tag	Struct tag for the relationship object	"-"
tag_ignore	List of column names that should have tags values set to '-'	[]
types	Register custom types. See more	"{}
aliases	Customize aliases. See more	{}
constraints	Define additional constraints. See more	{}
relationships	Define additional relationships. See more	{}
replacements	Define replacements for types. See more	[]
inflections	Define inflections for pluralization. See more	{}
generator	Customize the generator name in the top level comment of generated files	""

Aliases

Names are automatically generated for you. If you name your database entities properly you will likely have descriptive names generated in the end. However in the case where the names in your database are bad AND unchangeable, or bob's inference doesn't understand the names you do have (even though they are good and correct) you can use aliases to change the name of your tables, columns and relationships in the generated Go code.

Note: It is not required to provide all parts of all names. Anything left out will be inferred by default.

# Although team_names works fine without configuration, we use it here for illustrative purposes
aliases:
  team_names:
    up_plural: "TeamNames"
    up_singular: "TeamName"
    down_plural: "teamNames"
    down_singular: "teamName"
    columns: # Columns can be aliased by name
      uuid: "ID"
    relationships: # Relationships can be aliased by name
      team_id_fkey: "Owner"

Types

Custom types can be registered with the types key.
This will also allow you to edit the configuration of existing types, for example, to change how it is randomized by default.

When defining a type, you should provide the randomExpr. This is an expression that returns a random value of the type. It is used in factory.random_type().

There are things to note about writing the random expression:

• The expression must return a value of type T
• There is an existing variable of f which is of type *faker.Faker

To prevent generating a test for the random expression, set no_randomization_test to true. This is useful for low-cardinality types like bool.

In certain cases, it is necessary to compare values of the type to determine if they are equal. In such cases, you can provide a compareExpr which is an expression that compares two values of the type. Use the placeholders AAA and BBB as the types to be compared.

types:
  xml:
    # OPTIONAL: If this type is an alias of another type
    # this is useful to have custom randomization for a type e.g. xml
    alias_of: "string"
    # If this depends on another type, you can specify the type here
    depends_on:
      - "string"
    # The random expression for this type
    random_expr: |-
      tag := f.Lorem().Word()
      return fmt.Sprintf("<%s>%s</%s>", tag, f.Lorem().Word(), tag)
  type.JSON[json.RawMessage]:
    # If true, a test for the random expression will not be generated
    no_randomization_test: false
    imports:
      - '"encoding/json"'
      - '"github.com/stephenafamo/bob/types"'
    # To be used in factory.random_type
    # a variable `f` of type `faker.Faker` is available
    random_expr: |-
      s := &bytes.Buffer{}
      s.WriteRune('{')
      for i := 0; i < f.IntBetween(1, 5); i++ {
          if i > 0 {
              fmt.Fprint(s, ", ")
          }
          fmt.Fprintf(s, "%q:%q", f.Lorem().Word(), f.Lorem().Word())
      }
      s.WriteRune('}')
      return types.NewJSON[json.RawMessage](s.Bytes())`
    # Imports for the random expression
    random_expr_imports:
      - '"bytes"'
      - '"fmt"'
    # CompareExpr is used to compare two values of this type
    # if not provided, == is used
    # Used AAA and BBB as placeholders for the two values
    compare_expr: |-
      bytes.Equal(AAA.Val, BBB.Val)
    # Imports for the compare expression
    compare_expr_imports:
      - '"bytes"'

Replacements

There exists the ability to override types that the driver has inferred. The way to accomplish this is through the config file.

replacements:
  - tables: ["table_name"] # What tables to look inside. Matches all tables if empty

    # The match is a drivers.Column struct, and matches on almost all fields.
    # Notable exception for the unique bool. Matches are done
    # with "logical and" meaning it must match all specified matchers.
    # Boolean values are only checked if all the string specifiers match first,
    # and they must always match.
    #
    # Note there is precedence for types.match, more specific things should appear
    # further down in the config as once a matching rule is found it is executed
    # immediately.
    match:
      name: "username" # Matches the column name
      db_type: "varchar(255)" # Matches the database type
      default: "NULL" # Matches the default value
      comment: "The username" # Matches the column comment
      nullable: true # Matches the nullable value. Defaults to false.
      generated: false # Matches the generated value. Defaults to false.
      autoincr: false # Matches the autoincr value. Defaults to false.

    # The replace directive should either reference a pre-configured type, or a type
    # defined in the `types` configuration.
    replace: "mynull.String"

Constraints

It is possible to manually define additional constraints for your database. This is particularly useful if your database system or driver does not support constraints

This can also be used to create relationships since those are derived from foreign key constraints.

constraints:
  pilots:
    primary: # This will overwirte any existing primary key on the table
      name: "pilots_pkey"
      columns: [id]
    uniques: # These will be added to existing unique constraints
      - name: "pilot_name_unique"
        columns: [name]
      - name: "pilot_nickname_unique"
        columns: [nickname]
    foreign: # These will be added to existing foreign constraints
      - name: "pilot_to_jets"
        columns: [id]
        foreign_table: "jets"
        foreign_columns: [pilot_id]

Relationships

Relationships are automatically inferred from foreign key constraints. However, in certain cases, it is either not possible or not desireable to add a foreign key relationship.

We can manually describe relationships in the configuration:

relationships:
  users: # The table name
    - name: "custom_videos_relationship" # A unique identifier used to configure aliases
      never_required: true # If true, the relationship would never be assumed to be required. This means that the factory will never auto-generate related objects for it.
      sides:
        - from: "users" # Name of the source of the relationship
          to: "videos" # Table name of the other side of the relation
          # mapping of columns from source to destination
          columns:
            - [id, user_id]

          # Which side to modify, "from" or "to"
          # If not set, it will try to "guess" which side to modify
          # - if only one of the sides contains a primary key,
          #   it will choose to modify the other side
          # - If (both or none) of them contains a primary key,
          #   it will try with "Unique" columns
          # - If it still cannot choose, it defaults to "to"
          modify: "" | from" | "to"

Related Through

The configuration also allows us to describe relationships that span multiple tables. We achieve this by having multiple sides.

In this example configuration, we add a relationship of users to videos through teams. The generated user model with have a Videos relation.

relationships:
  users:
    - name: "users_to_videos_through_teams"
      sides:
        - from: "users"
          to: "teams"
          columns: [[team_id, id]]
        - from: "teams"
          to: "videos"
          columns: [[id, team_id]]

Related Where

The configuration also allows us to describe relationships that are not only based on matching columns but also columns with static values. For example, we may want to add a relationship to teams for verified members.

relationships:
  users:
    - name: "users_to_videos_through_teams"
      sides:
        - from: "teams"
          to: "users"
          columns: [[id, team_id]]
          to_where:
            - column: "verified"
              sql_value: "true"
              go_value: "true"

Inflections

With inflections, you can control the rules used to generate singular/plural variants. This is useful if a certain word or suffix is used multiple times and you do not wnat to create aliases for every instance.

inflections:
  plural: # Rules to convert a suffix to its plural form
    ium: ia
  plural_exact: # Rul