schema

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Version: v0.5.3 Latest Latest
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Published: Jun 1, 2015 License: MPL-2.0 Imports: 11 Imported by: 0

README

Terraform Helper Lib: schema

The schema package provides a high-level interface for writing resource providers for Terraform.

If you're writing a resource provider, we recommend you use this package.

The interface exposed by this package is much friendlier than trying to write to the Terraform API directly. The core Terraform API is low-level and built for maximum flexibility and control, whereas this library is built as a framework around that to more easily write common providers.

Documentation

Overview

schema is a high-level framework for easily writing new providers for Terraform. Usage of schema is recommended over attempting to write to the low-level plugin interfaces manually.

schema breaks down provider creation into simple CRUD operations for resources. The logic of diffing, destroying before creating, updating or creating, etc. is all handled by the framework. The plugin author only needs to implement a configuration schema and the CRUD operations and everything else is meant to just work.

A good starting point is to view the Provider structure.

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func HashString added in v0.5.0

func HashString(v interface{}) int

HashString hashes strings. If you want a Set of strings, this is the SchemaSetFunc you want.

Types

type BasicMapReader added in v0.3.7

type BasicMapReader map[string]string

BasicMapReader implements MapReader for a single map.

func (BasicMapReader) Access added in v0.3.7

func (r BasicMapReader) Access(k string) (string, bool)

func (BasicMapReader) Range added in v0.3.7

func (r BasicMapReader) Range(f func(string, string) bool) bool

type ConfigFieldReader added in v0.3.7

type ConfigFieldReader struct {
	Config *terraform.ResourceConfig
	Schema map[string]*Schema
	// contains filtered or unexported fields
}

ConfigFieldReader reads fields out of an untyped map[string]string to the best of its ability. It also applies defaults from the Schema. (The other field readers do not need default handling because they source fully populated data structures.)

func (*ConfigFieldReader) ReadField added in v0.3.7

func (r *ConfigFieldReader) ReadField(address []string) (FieldReadResult, error)

type ConfigureFunc

type ConfigureFunc func(*ResourceData) (interface{}, error)

ConfigureFunc is the function used to configure a Provider.

The interface{} value returned by this function is stored and passed into the subsequent resources as the meta parameter. This return value is usually used to pass along a configured API client, a configuration structure, etc.

type CreateFunc

type CreateFunc func(*ResourceData, interface{}) error

See Resource documentation.

type DeleteFunc

type DeleteFunc func(*ResourceData, interface{}) error

See Resource documentation.

type DiffFieldReader added in v0.3.7

type DiffFieldReader struct {
	Diff   *terraform.InstanceDiff
	Source FieldReader
	Schema map[string]*Schema
}

DiffFieldReader reads fields out of a diff structures.

It also requires access to a Reader that reads fields from the structure that the diff was derived from. This is usually the state. This is required because a diff on its own doesn't have complete data about full objects such as maps.

The Source MUST be the data that the diff was derived from. If it isn't, the behavior of this struct is undefined.

Reading fields from a DiffFieldReader is identical to reading from Source except the diff will be applied to the end result.

The "Exists" field on the result will be set to true if the complete field exists whether its from the source, diff, or a combination of both. It cannot be determined whether a retrieved value is composed of diff elements.

func (*DiffFieldReader) ReadField added in v0.3.7

func (r *DiffFieldReader) ReadField(address []string) (FieldReadResult, error)

type Equal added in v0.3.7

type Equal interface {
	Equal(interface{}) bool
}

Equal is an interface that checks for deep equality between two objects.

type ExistsFunc added in v0.3.7

type ExistsFunc func(*ResourceData, interface{}) (bool, error)

See Resource documentation.

type FieldReadResult added in v0.3.7

type FieldReadResult struct {
	// Value is the actual read value. NegValue is the _negative_ value
	// or the items that should be removed (if they existed). NegValue
	// doesn't make sense for primitives but is important for any
	// container types such as maps, sets, lists.
	Value          interface{}
	ValueProcessed interface{}

	// Exists is true if the field was found in the data. False means
	// it wasn't found if there was no error.
	Exists bool

	// Computed is true if the field was found but the value
	// is computed.
	Computed bool
}

FieldReadResult encapsulates all the resulting data from reading a field.

func (*FieldReadResult) ValueOrZero added in v0.3.7

func (r *FieldReadResult) ValueOrZero(s *Schema) interface{}

ValueOrZero returns the value of this result or the zero value of the schema type, ensuring a consistent non-nil return value.

type FieldReader added in v0.3.7

type FieldReader interface {
	ReadField([]string) (FieldReadResult, error)
}

FieldReaders are responsible for decoding fields out of data into the proper typed representation. ResourceData uses this to query data out of multiple sources: config, state, diffs, etc.

type FieldWriter added in v0.3.7

type FieldWriter interface {
	WriteField([]string, interface{}) error
}

FieldWriters are responsible for writing fields by address into a proper typed representation. ResourceData uses this to write new data into existing sources.

type MapFieldReader added in v0.3.7

type MapFieldReader struct {
	Map    MapReader
	Schema map[string]*Schema
}

MapFieldReader reads fields out of an untyped map[string]string to the best of its ability.

func (*MapFieldReader) ReadField added in v0.3.7

func (r *MapFieldReader) ReadField(address []string) (FieldReadResult, error)

type MapFieldWriter added in v0.3.7

type MapFieldWriter struct {
	Schema map[string]*Schema
	// contains filtered or unexported fields
}

MapFieldWriter writes data into a single map[string]string structure.

func (*MapFieldWriter) Map added in v0.3.7

func (w *MapFieldWriter) Map() map[string]string

Map returns the underlying map that is being written to.

func (*MapFieldWriter) WriteField added in v0.3.7

func (w *MapFieldWriter) WriteField(addr []string, value interface{}) error

type MapReader added in v0.3.7

type MapReader interface {
	Access(string) (string, bool)
	Range(func(string, string) bool) bool
}

MapReader is an interface that is given to MapFieldReader for accessing a "map". This can be used to have alternate implementations. For a basic map[string]string, use BasicMapReader.

type MultiLevelFieldReader added in v0.3.7

type MultiLevelFieldReader struct {
	Readers map[string]FieldReader
	Levels  []string
}

MultiLevelFieldReader reads from other field readers, merging their results along the way in a specific order. You can specify "levels" and name them in order to read only an exact level or up to a specific level.

This is useful for saying things such as "read the field from the state and config and merge them" or "read the latest value of the field".

func (*MultiLevelFieldReader) ReadField added in v0.3.7

func (r *MultiLevelFieldReader) ReadField(address []string) (FieldReadResult, error)

func (*MultiLevelFieldReader) ReadFieldExact added in v0.3.7

func (r *MultiLevelFieldReader) ReadFieldExact(
	address []string, level string) (FieldReadResult, error)

func (*MultiLevelFieldReader) ReadFieldMerge added in v0.3.7

func (r *MultiLevelFieldReader) ReadFieldMerge(
	address []string, level string) (FieldReadResult, error)

type MultiMapReader added in v0.3.7

type MultiMapReader []map[string]string

MultiMapReader reads over multiple maps, preferring keys that are founder earlier (lower number index) vs. later (higher number index)

func (MultiMapReader) Access added in v0.3.7

func (r MultiMapReader) Access(k string) (string, bool)

func (MultiMapReader) Range added in v0.3.7

func (r MultiMapReader) Range(f func(string, string) bool) bool

type Provider

type Provider struct {
	// Schema is the schema for the configuration of this provider. If this
	// provider has no configuration, this can be omitted.
	//
	// The keys of this map are the configuration keys, and the value is
	// the schema describing the value of the configuration.
	Schema map[string]*Schema

	// ResourcesMap is the list of available resources that this provider
	// can manage, along with their Resource structure defining their
	// own schemas and CRUD operations.
	//
	// Provider automatically handles routing operations such as Apply,
	// Diff, etc. to the proper resource.
	ResourcesMap map[string]*Resource

	// ConfigureFunc is a function for configuring the provider. If the
	// provider doesn't need to be configured, this can be omitted.
	//
	// See the ConfigureFunc documentation for more information.
	ConfigureFunc ConfigureFunc
	// contains filtered or unexported fields
}

Provider represents a resource provider in Terraform, and properly implements all of the ResourceProvider API.

By defining a schema for the configuration of the provider, the map of supporting resources, and a configuration function, the schema framework takes over and handles all the provider operations for you.

After defining the provider structure, it is unlikely that you'll require any of the methods on Provider itself.

func (*Provider) Apply

Apply implementation of terraform.ResourceProvider interface.

func (*Provider) Configure

func (p *Provider) Configure(c *terraform.ResourceConfig) error

Configure implementation of terraform.ResourceProvider interface.

func (*Provider) Diff

Diff implementation of terraform.ResourceProvider interface.

func (*Provider) Input added in v0.3.0

Input implementation of terraform.ResourceProvider interface.

func (*Provider) InternalValidate

func (p *Provider) InternalValidate() error

InternalValidate should be called to validate the structure of the provider.

This should be called in a unit test for any provider to verify before release that a provider is properly configured for use with this library.

func (*Provider) Meta

func (p *Provider) Meta() interface{}

Meta returns the metadata associated with this provider that was returned by the Configure call. It will be nil until Configure is called.

func (*Provider) Refresh

Refresh implementation of terraform.ResourceProvider interface.

func (*Provider) Resources

func (p *Provider) Resources() []terraform.ResourceType

Resources implementation of terraform.ResourceProvider interface.

func (*Provider) SetMeta

func (p *Provider) SetMeta(v interface{})

SetMeta can be used to forcefully set the Meta object of the provider. Note that if Configure is called the return value will override anything set here.

func (*Provider) Validate

func (p *Provider) Validate(c *terraform.ResourceConfig) ([]string, []error)

Validate implementation of terraform.ResourceProvider interface.

func (*Provider) ValidateResource

func (p *Provider) ValidateResource(
	t string, c *terraform.ResourceConfig) ([]string, []error)

ValidateResource implementation of terraform.ResourceProvider interface.

type ReadFunc

type ReadFunc func(*ResourceData, interface{}) error

See Resource documentation.

type Resource

type Resource struct {
	// Schema is the schema for the configuration of this resource.
	//
	// The keys of this map are the configuration keys, and the values
	// describe the schema of the configuration value.
	//
	// The schema is used to represent both configurable data as well
	// as data that might be computed in the process of creating this
	// resource.
	Schema map[string]*Schema

	// SchemaVersion is the version number for this resource's Schema
	// definition. The current SchemaVersion stored in the state for each
	// resource. Provider authors can increment this version number
	// when Schema semantics change. If the State's SchemaVersion is less than
	// the current SchemaVersion, the InstanceState is yielded to the
	// MigrateState callback, where the provider can make whatever changes it
	// needs to update the state to be compatible to the latest version of the
	// Schema.
	//
	// When unset, SchemaVersion defaults to 0, so provider authors can start
	// their Versioning at any integer >= 1
	SchemaVersion int

	// MigrateState is responsible for updating an InstanceState with an old
	// version to the format expected by the current version of the Schema.
	//
	// It is called during Refresh if the State's stored SchemaVersion is less
	// than the current SchemaVersion of the Resource.
	//
	// The function is yielded the state's stored SchemaVersion and a pointer to
	// the InstanceState that needs updating, as well as the configured
	// provider's configured meta interface{}, in case the migration process
	// needs to make any remote API calls.
	MigrateState StateMigrateFunc

	// The functions below are the CRUD operations for this resource.
	//
	// The only optional operation is Update. If Update is not implemented,
	// then updates will not be supported for this resource.
	//
	// The ResourceData parameter in the functions below are used to
	// query configuration and changes for the resource as well as to set
	// the ID, computed data, etc.
	//
	// The interface{} parameter is the result of the ConfigureFunc in
	// the provider for this resource. If the provider does not define
	// a ConfigureFunc, this will be nil. This parameter should be used
	// to store API clients, configuration structures, etc.
	//
	// If any errors occur during each of the operation, an error should be
	// returned. If a resource was partially updated, be careful to enable
	// partial state mode for ResourceData and use it accordingly.
	//
	// Exists is a function that is called to check if a resource still
	// exists. If this returns false, then this will affect the diff
	// accordingly. If this function isn't set, it will not be called. It
	// is highly recommended to set it. The *ResourceData passed to Exists
	// should _not_ be modified.
	Create CreateFunc
	Read   ReadFunc
	Update UpdateFunc
	Delete DeleteFunc
	Exists ExistsFunc
}

Resource represents a thing in Terraform that has a set of configurable attributes and a lifecycle (create, read, update, delete).

The Resource schema is an abstraction that allows provider writers to worry only about CRUD operations while off-loading validation, diff generation, etc. to this higher level library.

func (*Resource) Apply

func (r *Resource) Apply(
	s *terraform.InstanceState,
	d *terraform.InstanceDiff,
	meta interface{}) (*terraform.InstanceState, error)

Apply creates, updates, and/or deletes a resource.

func (*Resource) Diff

Diff returns a diff of this resource and is API compatible with the ResourceProvider interface.

func (*Resource) InternalValidate

func (r *Resource) InternalValidate(topSchemaMap schemaMap) error

InternalValidate should be called to validate the structure of the resource.

This should be called in a unit test for any resource to verify before release that a resource is properly configured for use with this library.

Provider.InternalValidate() will automatically call this for all of the resources it manages, so you don't need to call this manually if it is part of a Provider.

func (*Resource) Refresh

func (r *Resource) Refresh(
	s *terraform.InstanceState,
	meta interface{}) (*terraform.InstanceState, error)

Refresh refreshes the state of the resource.

func (*Resource) Validate

func (r *Resource) Validate(c *terraform.ResourceConfig) ([]string, []error)

Validate validates the resource configuration against the schema.

type ResourceData

type ResourceData struct {
	// contains filtered or unexported fields
}

ResourceData is used to query and set the attributes of a resource.

ResourceData is the primary argument received for CRUD operations on a resource as well as configuration of a provider. It is a powerful structure that can be used to not only query data, but check for changes, define partial state updates, etc.

The most relevant methods to take a look at are Get, Set, and Partial.

func (*ResourceData) ConnInfo

func (d *ResourceData) ConnInfo() map[string]string

ConnInfo returns the connection info for this resource.

func (*ResourceData) Get

func (d *ResourceData) Get(key string) interface{}

Get returns the data for the given key, or nil if the key doesn't exist in the schema.

If the key does exist in the schema but doesn't exist in the configuration, then the default value for that type will be returned. For strings, this is "", for numbers it is 0, etc.

If you want to test if something is set at all in the configuration, use GetOk.

func (*ResourceData) GetChange

func (d *ResourceData) GetChange(key string) (interface{}, interface{})

GetChange returns the old and new value for a given key.

HasChange should be used to check if a change exists. It is possible that both the old and new value are the same if the old value was not set and the new value is. This is common, for example, for boolean fields which have a zero value of false.

func (*ResourceData) GetOk

func (d *ResourceData) GetOk(key string) (interface{}, bool)

GetOk returns the data for the given key and whether or not the key has been set to a non-zero value at some point.

The first result will not necessarilly be nil if the value doesn't exist. The second result should be checked to determine this information.

func (*ResourceData) HasChange

func (d *ResourceData) HasChange(key string) bool

HasChange returns whether or not the given key has been changed.

func (*ResourceData) Id

func (d *ResourceData) Id() string

Id returns the ID of the resource.

func (*ResourceData) Partial

func (d *ResourceData) Partial(on bool)

Partial turns partial state mode on/off.

When partial state mode is enabled, then only key prefixes specified by SetPartial will be in the final state. This allows providers to return partial states for partially applied resources (when errors occur).

func (*ResourceData) Set

func (d *ResourceData) Set(key string, value interface{}) error

Set sets the value for the given key.

If the key is invalid or the value is not a correct type, an error will be returned.

func (*ResourceData) SetConnInfo

func (d *ResourceData) SetConnInfo(v map[string]string)

SetConnInfo sets the connection info for a resource.

func (*ResourceData) SetId

func (d *ResourceData) SetId(v string)

SetId sets the ID of the resource. If the value is blank, then the resource is destroyed.

func (*ResourceData) SetPartial

func (d *ResourceData) SetPartial(k string)

SetPartial adds the key to the final state output while in partial state mode. The key must be a root key in the schema (i.e. it cannot be "list.0").

If partial state mode is disabled, then this has no effect. Additionally, whenever partial state mode is toggled, the partial data is cleared.

func (*ResourceData) State

func (d *ResourceData) State() *terraform.InstanceState

State returns the new InstanceState after the diff and any Set calls.

type Schema

type Schema struct {
	// Type is the type of the value and must be one of the ValueType values.
	//
	// This type not only determines what type is expected/valid in configuring
	// this value, but also what type is returned when ResourceData.Get is
	// called. The types returned by Get are:
	//
	//   TypeBool - bool
	//   TypeInt - int
	//   TypeFloat - float64
	//   TypeString - string
	//   TypeList - []interface{}
	//   TypeMap - map[string]interface{}
	//   TypeSet - *schema.Set
	//
	Type ValueType

	// If one of these is set, then this item can come from the configuration.
	// Both cannot be set. If Optional is set, the value is optional. If
	// Required is set, the value is required.
	//
	// One of these must be set if the value is not computed. That is:
	// value either comes from the config, is computed, or is both.
	Optional bool
	Required bool

	// If this is non-nil, then this will be a default value that is used
	// when this item is not set in the configuration/state.
	//
	// DefaultFunc can be specified if you want a dynamic default value.
	// Only one of Default or DefaultFunc can be set.
	//
	// If Required is true above, then Default cannot be set. DefaultFunc
	// can be set with Required. If the DefaultFunc returns nil, then there
	// will be no default and the user will be asked to fill it in.
	//
	// If either of these is set, then the user won't be asked for input
	// for this key if the default is not nil.
	Default     interface{}
	DefaultFunc SchemaDefaultFunc

	// Description is used as the description for docs or asking for user
	// input. It should be relatively short (a few sentences max) and should
	// be formatted to fit a CLI.
	Description string

	// InputDefault is the default value to use for when inputs are requested.
	// This differs from Default in that if Default is set, no input is
	// asked for. If Input is asked, this will be the default value offered.
	InputDefault string

	// The fields below relate to diffs.
	//
	// If Computed is true, then the result of this value is computed
	// (unless specified by config) on creation.
	//
	// If ForceNew is true, then a change in this resource necessitates
	// the creation of a new resource.
	//
	// StateFunc is a function called to change the value of this before
	// storing it in the state (and likewise before comparing for diffs).
	// The use for this is for example with large strings, you may want
	// to simply store the hash of it.
	Computed  bool
	ForceNew  bool
	StateFunc SchemaStateFunc

	// The following fields are only set for a TypeList or TypeSet Type.
	//
	// Elem must be either a *Schema or a *Resource only if the Type is
	// TypeList, and represents what the element type is. If it is *Schema,
	// the element type is just a simple value. If it is *Resource, the
	// element type is a complex structure, potentially with its own lifecycle.
	Elem interface{}

	// The following fields are only valid for a TypeSet type.
	//
	// Set defines a function to determine the unique ID of an item so that
	// a proper set can be built.
	Set SchemaSetFunc

	// ComputedWhen is a set of queries on the configuration. Whenever any
	// of these things is changed, it will require a recompute (this requires
	// that Computed is set to true).
	//
	// NOTE: This currently does not work.
	ComputedWhen []string

	// ConflictsWith is a set of schema keys that conflict with this schema
	ConflictsWith []string

	// When Deprecated is set, this attribute is deprecated.
	//
	// A deprecated field still works, but will probably stop working in near
	// future. This string is the message shown to the user with instructions on
	// how to address the deprecation.
	Deprecated string

	// When Removed is set, this attribute has been removed from the schema
	//
	// Removed attributes can be left in the Schema to generate informative error
	// messages for the user when they show up in resource configurations.
	// This string is the message shown to the user with instructions on
	// what do to about the removed attribute.
	Removed string
}

Schema is used to describe the structure of a value.

Read the documentation of the struct elements for important details.

func (*Schema) DefaultValue added in v0.3.7

func (s *Schema) DefaultValue() (interface{}, error)

Returns a default value for this schema by either reading Default or evaluating DefaultFunc. If neither of these are defined, returns nil.

func (*Schema) GoString

func (s *Schema) GoString() string

type SchemaDefaultFunc added in v0.3.0

type SchemaDefaultFunc func() (interface{}, error)

SchemaDefaultFunc is a function called to return a default value for a field.

func EnvDefaultFunc added in v0.3.7

func EnvDefaultFunc(k string, dv interface{}) SchemaDefaultFunc

EnvDefaultFunc is a helper function that returns the value of the given environment variable, if one exists, or the default value otherwise.

func MultiEnvDefaultFunc added in v0.3.7

func MultiEnvDefaultFunc(ks []string, dv interface{}) SchemaDefaultFunc

MultiEnvDefaultFunc is a helper function that returns the value of the first environment variable in the given list that returns a non-empty value. If none of the environment variables return a value, the default value is returned.

type SchemaSetFunc

type SchemaSetFunc func(interface{}) int

SchemaSetFunc is a function that must return a unique ID for the given element. This unique ID is used to store the element in a hash.

type SchemaStateFunc

type SchemaStateFunc func(interface{}) string

SchemaStateFunc is a function used to convert some type to a string to be stored in the state.

type Set

type Set struct {
	F SchemaSetFunc
	// contains filtered or unexported fields
}

Set is a set data structure that is returned for elements of type TypeSet.

func CopySet added in v0.5.0

func CopySet(otherSet *Set) *Set

CopySet returns a copy of another set.

func NewSet added in v0.3.1

func NewSet(f SchemaSetFunc, items []interface{}) *Set

NewSet is a convenience method for creating a new set with the given items.

func (*Set) Add

func (s *Set) Add(item interface{})

Add adds an item to the set if it isn't already in the set.

func (*Set) Contains

func (s *Set) Contains(item interface{}) bool

Contains checks if the set has the given item.

func (*Set) Difference

func (s *Set) Difference(other *Set) *Set

Differences performs a set difference of the two sets, returning a new third set that has only the elements unique to this set.

func (*Set) Equal added in v0.3.7

func (s *Set) Equal(raw interface{}) bool

func (*Set) GoString added in v0.3.7

func (s *Set) GoString() string

func (*Set) Intersection

func (s *Set) Intersection(other *Set) *Set

Intersection performs the set intersection of the two sets and returns a new third set.

func (*Set) Len

func (s *Set) Len() int

Len returns the amount of items in the set.

func (*Set) List

func (s *Set) List() []interface{}

List returns the elements of this set in slice format.

The order of the returned elements is deterministic. Given the same set, the order of this will always be the same.

func (*Set) Remove added in v0.5.0

func (s *Set) Remove(item interface{})

Remove removes an item if it's already in the set. Idempotent.

func (*Set) Union

func (s *Set) Union(other *Set) *Set

Union performs the set union of the two sets and returns a new third set.

type StateMigrateFunc added in v0.4.0

type StateMigrateFunc func(
	int, *terraform.InstanceState, interface{}) (*terraform.InstanceState, error)

See Resource documentation.

type UpdateFunc

type UpdateFunc func(*ResourceData, interface{}) error

See Resource documentation.

type ValueType

type ValueType int

ValueType is an enum of the type that can be represented by a schema.

const (
	TypeInvalid ValueType = iota
	TypeBool
	TypeInt
	TypeFloat
	TypeString
	TypeList
	TypeMap
	TypeSet
)

func (ValueType) String added in v0.3.7

func (i ValueType) String() string

func (ValueType) Zero added in v0.3.7

func (t ValueType) Zero() interface{}

Zero returns the zero value for a type.

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