Terraform JSON Paths

An exact location within Terraform JSON data is referred to as a Terraform JSON or tfjson path.

Usage

Example uses in the testing module include:

The ExpectUnknownValue() and ExpectSensitiveValue() built-in plan checks for specifying an attribute to make the check assertion against.

Concepts

Terraform JSON Paths are designed around the underlying Go types corresponding to the Terraform JSON implementation of a schema and schema-based data. The terraform-json library serves as the de-facto documentation for Terraform JSON data. Paths are always absolute and start from the root, or top level, of a JSON object.

Given the tree structure of JSON objects, descriptions of paths and their steps borrow certain hierarchy terminology such as parent and child. A parent path describes a path without one or more of the final steps of a given path, or put differently, a partial path closer to the root of the object. A child path describes a path with one or more additional steps beyond a given path, or put differently, a path containing the given path but further from the root of the object.

Building Paths

The terraform-plugin-testing module implementation for tfjson paths is in the tfjsonpath package, with the tfjsonpath.Path type being the main provider developer interaction point. Call the tfjsonpath.New() function with a property name at the root of the object to begin a path.

Given the following JSON object

{
   "first_name": "John",
   "last_name": "Doe",
   "age": 18,
   "street_address": "123 Terraform Dr.",
   "phone_numbers": [
      { "mobile": "111-111-1111" },
      { "home": "222-222-2222" }
   ]
}

The call to tfjsonpath.New() which matches the location of first_name string value is:

tfjsonpath.New("first_name")

Once a tfjsonpath.Path is started, it supports a builder pattern, which allows for chaining method calls to construct a full path.

The path which matches the location of the string value "222-222-222" is:

tfjsonpath.New("phone_numbers").AtSliceIndex(1).AtMapKey("home")

The most common usage of tfjsonpath.Path is to specify an attribute within Terraform JSON data. When used in this way, the root of the JSON object is the same as the root of a schema. The follow sections show how to build attribute paths for primitive attributes, aggregate attributes, nested attributes, and blocks.

Building Attribute Paths

The following table shows the different tfjsonpath.Path type methods associated with building paths for attribute implementations. Attribute types that cannot be traversed further are shown with N/A (not applicable).

Framework Attribute Type	SDKv2 Attribute Type	Child Path Method
`schema.BoolAttribute`	`schema.TypeBool`	N/A
`schema.Float64Attribute`	`schema.TypeFloat`	N/A
`schema.Int64Attribute`	`schema.TypeInt`	N/A
`schema.ListAttribute`	`schema.TypeList`	`AtSliceIndex()`
`schema.MapAttribute`	`schema.TypeMap`	`AtMapKey()`
`schema.NumberAttribute`	N/A	N/A
`schema.ObjectAttribute`	N/A	`AtMapKey()`
`schema.SetAttribute`	`schema.TypeSet`	`AtSliceIndex()`
`schema.StringAttribute`	`schema.TypeString`	N/A

Given this example schema with a root attribute named example_root_attribute:

//Terraform Plugin Framework
schema.Schema{
    Attributes: map[string]schema.Attribute{
        "example_root_attribute": schema.StringAttribute{
            Required: true,
        },
    },
}

//Terraform Plugin SDKv2
Schema: map[string]*schema.Schema{
    "example_root_attribute": {
        Type:     schema.TypeString,
        Required: true,
    },
},

And the following Terraform JSON object representation of the state:

{
    "example_root_attribute": "example-value"
}

The call to tfjsonpath.New() which matches the location of example_root_attribute string value is:

tfjsonpath.New("example_root_attribute")

For blocks, the beginning of a path is similarly defined.

Given this example schema with a root block named example_root_block:

//Terraform Plugin Framework
schema.Schema{
    Blocks: map[string]schema.Block{
        "example_root_block": schema.ListNestedBlock{
            NestedObject: schema.NestedBlockObject{/* ... */},
        },
    },
}

//Terraform Plugin SDKv2
Schema: map[string]*schema.Schema{
    "example_root_block": {
        Type:     schema.TypeList,
        Elem: &schema.Resource{
            Schema: map[string]*schema.Schema{/* ... */},
        },
    },
},

And the following Terraform JSON object representation of the state:

{
    "example_root_block": [
        {}
    ]
}

The call to tfjsonpath.New() which matches the location of example_root_block slice value is:

tfjsonpath.New("example_root_block")

Building Aggregate Type Attribute Paths

Given following schema example:

//Terraform Plugin Framework
schema.Schema{
    Attributes: map[string]schema.Attribute{
        "root_map_attribute": schema.MapAttribute{
            ElementType: types.StringType,
            Required: true,
        },
        "root_list_attribute": schema.ListAttribute{
            ElementType: types.StringType,
            Required: true,
        },
        "root_set_attribute": schema.SetAttribute{
            ElementType: types.StringType,
            Required: true,
        },
    },
}

//Terraform Plugin SDKv2
Schema: map[string]*schema.Schema{
    "root_map_attribute": {
        Type: schema.TypeMap,
        Elem: &schema.Schema{
            Type: schema.TypeString,
        },
        Required: true,
    },
    "root_list_attribute": {
        Type: schema.TypeList,
        Elem: &schema.Schema{
            Type: schema.TypeString,
        },
        Required: true,
    },
    "root_set_attribute": {
        Type: schema.TypeSet,
        Elem: &schema.Schema{
            Type: schema.TypeString,
        },
        Required: true,
    },
},

And the following Terraform JSON object representation of the state:

{
    "root_map_attribute": {
        "example-key": "map-value"
    },
    "root_list_attribute": [
        "list-value1",
        "list-value2"
    ],
    "root_set_attribute": [
        "set-value1",
        "set-value2"
    ]
}

The path which matches the string value associated with the map key example-key of the root_map_attribute attribute is:

tfjsonpath.New("root_map_attribute").AtMapKey("example-key")

The path which matches the string value list-value1 in the root_list_attribute attribute is:

tfjsonpath.New("root_list_attribute").AtSliceIndex(0)

The path which matches the string value set-value2 in the root_set_attribute attribute is:

tfjsonpath.New("root_set_attribute").AtSliceIndex(1)

Note that because Sets are unordered in Terraform, the ordering of Set elements in the Terraform JSON data is not guaranteed to be the same as the ordering in the configuration.

Building Nested Attribute Paths

The following table shows the different tfjsonpath.Path type methods associated with building paths for nested attributes.

Nested Attribute Type	Child Path Method(s)
`schema.ListNestedAttribute`	`AtSliceIndex().AtMapKey()`
`schema.MapNestedAttribute`	`AtMapKey().AtMapKey()`
`schema.SetNestedAttribute`	`AtSliceIndex().AtMapKey()`
`schema.SingleNestedAttribute`	`AtMapKey()`

Nested attributes eventually follow the same path rules as attributes at child paths, which follow the methods shown in the Building Attribute Paths section.

Building List Nested Attributes Paths

An attribute that implements schema.ListNestedAttribute conceptually is a slice containing a map with attribute names as keys.

Given the following schema example:

schema.Schema{
    Attributes: map[string]schema.Attribute{
        "root_list_attribute": schema.ListNestedAttribute{
            NestedObject: schema.NestedAttributeObject{
                Attributes: map[string]schema.Attribute{
                    "nested_string_attribute": schema.StringAttribute{
                        Required: true,
                    },
                },
            },
            Required: true,
        },
    },
}

And the following Terraform JSON object representation of the state:

{
    "root_list_attribute": [
        {
          "nested_string_attribute": "value"
        }
    ]
}

The path which matches the slice associated with the root_list_attribute attribute is:

tfjsonpath.New("root_list_attribute")

The path which matches the first map in the slice associated with the root_list_attribute attribute is:

tfjsonpath.New("root_list_attribute").AtSliceIndex(0)

The path which matches the nested_string_attribute map key in the first map in the slice associated with root_list_attribute attribute is:

tfjsonpath.New("root_list_attribute").AtSliceIndex(0).AtMapKey("nested_string_attribute")

Building Map Nested Attributes Paths

An attribute that implements schema.MapNestedAttribute conceptually is a map containing values of maps with attribute names as keys.

Given the following schema example:

schema.Schema{
    Attributes: map[string]schema.Attribute{
        "root_map_attribute": schema.MapNestedAttribute{
            NestedObject: schema.NestedAttributeObject{
                Attributes: map[string]schema.Attribute{
                    "nested_string_attribute": schema.StringAttribute{
                        Required: true,
                    },
                },
            },
            Required: true,
        },
    },
}

And the following Terraform JSON object representation of the state:

{
    "root_map_attribute": {
        "example-key" : {
          "nested_string_attribute": "value"
        }
    }
}

The path which matches the map associated with the root_map_attribute attribute is:

tfjsonpath.New("root_map_attribute")

The path which matches the "example-key" object in the map associated with the root_map_attribute attribute is:

tfjsonpath.New("root_map_attribute").AtMapKey("example-key")

The path which matches the nested_string_attribute string value in a "example-key" object in the map associated with root_map_attribute attribute is:

tfjsonpath.New("root_map_attribute").AtMapKey("example-key").AtMapKey("nested_string_attribute")

Building Set Nested Attributes Paths

An attribute that implements schema.SetNestedAttribute conceptually is a slice containing maps with attribute names as keys.

Given the following schema example:

schema.Schema{
    Attributes: map[string]schema.Attribute{
        "root_set_attribute": schema.SetNestedAttribute{
            NestedObject: schema.NestedAttributeObject{
                Attributes: map[string]schema.Attribute{
                    "nested_string_attribute": schema.StringAttribute{
                        Required: true,
                    },
                },
            },
            Required: true,
        },
    },
}

And the following Terraform JSON object representation of the state:

{
    "root_set_attribute": [
        {
          "nested_string_attribute": "value"
        }
    ]
}

The path which matches the set associated with the root_set_attribute attribute is:

tfjsonpath.New("root_set_attribute")

The path which matches the first map in the slice associated with the root_set_attribute attribute is:

tfjsonpath.New("root_set_attribute").AtSliceIndex(0)

Note that because Sets are unordered in Terraform, the ordering of Set elements in the Terraform JSON data is not guaranteed to be the same as the ordering in the configuration.

The path which matches the nested_string_attribute map key in the first map in the slice associated with root_set_attribute attribute is:

tfjsonpath.New("root_set_attribute").AtSliceIndex(0).AtMapKey("nested_string_attribute")

Building Single Nested Attributes Paths

An attribute that implements schema.SingleNestedAttribute conceptually is a map with attribute names as keys.

Given the following schema example:

schema.Schema{
    Attributes: map[string]schema.Attribute{
        "root_grouped_attributes": schema.SingleNestedAttribute{
            Attributes: map[string]schema.Attribute{
                "nested_string_attribute": schema.StringAttribute{
                    Required: true,
                },
            },
            Required: true,
        },
    },
}

And the following Terraform JSON object representation of the state:

{
    "root_grouped_attributes": {
      "nested_string_attribute": "value"
    }
}

The path which matches the map associated with the root_grouped_attributes attribute is:

tfjsonpath.New("root_grouped_attributes")

The path which matches the nested_string_attribute string value in the map associated with the root_grouped_attributes attribute is:

tfjsonpath.New("root_grouped_attributes").AtMapKey("nested_string_attribute")

Building Block Paths

The following table shows the different tfjsonpath.Path type methods associated with building paths for blocks.

Block Type	Child Path Method(s)
`ListNestedBlock`	`AtSliceIndex().AtMapKey()`
`SetNestedBlock`	`AtSliceIndex().AtMapKey()`
`SingleNestedBlock`	`AtMapKey()`

Blocks can implement nested blocks. Paths can continue to be built using the associated method with each level of the block type.

Blocks eventually follow the same path rules as attributes at child paths, which follow the methods shown in the Building Attribute Paths section. Blocks cannot contain nested attributes.

Building List Block Paths

A ListNestedBlock conceptually is a slice containing maps with attribute or block names as keys.

Given following schema example:

//Terraform Plugin Framework
schema.Schema{
    Blocks: map[string]schema.Block{
        "root_list_block": schema.ListNestedBlock{
            NestedObject: schema.NestedBlockObject{
                Attributes: map[string]schema.Attribute{
                    "block_string_attribute": schema.StringAttribute{
                        Required: true,
                    },
                },
                Blocks: map[string]schema.Block{
                    "nested_list_block": schema.ListNestedBlock{
                        NestedObject: schema.NestedBlockObject{
                            Attributes: map[string]schema.Attribute{
                                "nested_block_string_attribute": schema.StringAttribute{
                                    Required: true,
                                },
                            },
                        },
                    },
                },
            },
        },
    },
}

//Terraform Plugin SDKv2
Schema: map[string]*schema.Schema{
    "root_list_block": {
        Type:     schema.TypeList,
        Elem: &schema.Resource{
            Schema: map[string]*schema.Schema{
                "block_string_attribute": {
                    Type:     schema.TypeString,
                    Required: true,
                },
                "nested_list_block": {
                    Type: schema.TypeList,
                    Elem: &schema.Resource{
                        Schema: map[string]*schema.Schema{
                            "nested_block_string_attribute": {
                                Type: schema.TypeString,
                                Required: true,
                            },
                        },
                    },
                },
            },
        },
    },
},

And the following Terraform JSON object representation of the state:

{
    "root_list_block": [
      {
        "block_string_attribute": "value1",
        "nested_list_block": [
            {"nested_block_string_attribute":  "value2"}
        ]
      }
    ]
}

The path which matches the slice associated with the root_list_block block is:

tfjsonpath.New("root_list_block")

The path which matches the first map in the slice associated with the root_list_block block is:

tfjsonpath.New("root_list_block").AtSliceIndex(0)

The path which matches the block_string_attribute string value in the first map in the slice associated with root_list_block block is:

tfjsonpath.New("root_list_block").AtSliceIndex(0).AtMapKey("block_string_attribute")

The path which matches the nested_list_block slice in the first object in the slice associated with root_list_block block is:

tfjsonpath.New("root_list_block").AtSliceIndex(0).AtMapKey("nested_list_block")

The path which matches the nested_block_string_attribute string value in the first map in the slice associated with the nested_list_block slice in the first map in the slice associated with root_list_block block is:

tfjsonpath.New("root_list_block").AtSliceIndex(0).AtMapKey("nested_list_block").AtSliceIndex(0).AtMapKey("nested_block_string_attribute")

Building Set Block Paths

A SetNestedBlock conceptually is a slice containing maps with attribute or block names as keys.

Given following schema example:

//Terraform Plugin Framework
schema.Schema{
    Blocks: map[string]schema.Block{
        "root_set_block": schema.SetNestedBlock{
            NestedObject: schema.NestedBlockObject{
                Attributes: map[string]schema.Attribute{
                    "block_string_attribute": schema.StringAttribute{
                        Optional: true,
                    },
                },
            },
        },
    },
}

//Terraform Plugin SDKv2
Schema: map[string]*schema.Schema{
    "root_set_block": {
        Type:     schema.TypeSet,
        Elem: &schema.Resource{
            Schema: map[string]*schema.Schema{
                "block_string_attribute": {
                    Type:     schema.TypeString,
                    Optional: true,
                },
            },
        },
    },
},

And the following Terraform JSON object representation of the state:

{
    "root_set_block": [
      {
        "block_string_attribute": "value1"
      }
    ]
}

The path which matches the slice associated with the root_set_block block is:

tfjsonpath.New("root_set_block")

The path which matches the first map in the slice associated with the root_set_block block is:

tfjsonpath.New("root_set_block").AtSliceIndex(0)

Note that because sets are unordered in Terraform, the ordering of set elements in the Terraform JSON data is not guaranteed to be the same as the ordering in the configuration.

The path which matches the block_string_attribute string value in the first map in the slice associated with root_set_block block is:

tfjsonpath.New("root_set_block").AtSliceIndex(0).AtMapKey("block_string_attribute")

Building Single Block Paths

A SingleNestedBlock conceptually is a map with attribute or block names as keys.

Given following schema example:

//Terraform Plugin Framework
schema.Schema{
    Blocks: map[string]schema.Block{
        "root_single_block": schema.SingleNestedBlock{
            Attributes: map[string]schema.Attribute{
                "block_string_attribute": schema.StringAttribute{
                    Required: true,
                },
            },
            Blocks: map[string]schema.Block{
                "nested_single_block": schema.SingleNestedBlock{
                    Attributes: map[string]schema.Attribute{
                        "nested_block_string_attribute": schema.StringAttribute{
                            Required: true,
                        },
                    },
                },
            },
        },
    },
}

The path which matches the map associated with the root_single_block block is:

tfjsonpath.New("root_single_block")

The path which matches the block_string_attribute string value in the map associated with root_single_block block is:

tfjsonpath.New("root_single_block").AtMapKey("block_string_attribute")

The path which matches the nested_single_block map in the map associated with root_single_block block is:

tfjsonpath.New("root_single_block").AtMapKey("nested_single_block")

The path which matches the nested_block_string_attribute string value in the map associated with the nested_single_block in the map associated with root_single_block block is:

tfjsonpath.New("root_single_block").AtMapKey("nested_single_block").AtMapKey("nested_block_string_attribute")