In this article I have explored all the examples on how to use list of strings with for_each for loop in Terraform resource and output block.
In this first block of example I have defined variable named marvel, it's type is list and value has string names of superheroes inside [ ] square bracket as shown in below example.
variable "marvel" { type = list(any) default = ["IronMan","Thor","Hulk","HawkEye","SpiderMan"] }
In the first demo to use list with for_each loop inside resource block I have simply converted it to set with toset() function. To iterate through the list I am using each.value which has the content of each string element from list. You can also use each.key instead.
resource "null_resource" "avengers_captainmarvel" { for_each = toset(var.marvel) provisioner "local-exec" { command = "echo ${each.value} is an Avenger!" } }
Following in the second example I am using for loop with for_each to create key=value pair map from variable list type. Key and value both will be the same in this case. You can use each.key or each.value to iterate through the list.
resource "null_resource" "avengers_blackwidow" { for_each = { for avenger in var.marvel : avenger => avenger } provisioner "local-exec" { command = "echo ${each.value} is an Avenger!" } }
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In this final example, we'll explore how to utilize list within a resource block using the count and length() functions. Unlike previous examples, all the loop logic is encapsulated within the for_each loop. By leveraging count to retrieve the length of the list, we can use the count index to iterate through the list elements. This approach enables efficient and concise resource creation based on list values.
In this example, count is set to the length of var.marvel, allowing us to access each element using count.index. This technique streamlines resource creation and management, making it a valuable addition to your Terraform toolkit.
In this final example, we'll explore how to utilize list within a resource block using the count and length() functions. Unlike previous examples, all the loop logic is encapsulated within the for_each loop. By leveraging count to retrieve the length of the list, we can use the count index to iterate through the list elements. This approach enables efficient and concise resource creation based on list values.
In this example, count is set to the length of var.marvel, allowing us to access each element using count.index. This technique streamlines resource creation and management, making it a valuable addition to your Terraform toolkit.
resource "null_resource" "avengers_scarletwitch" { count = length(var.marvel) provisioner "local-exec" { command = "echo ${var.marvel[count.index]} is an Avenger!" } }
Apart from resource block, This is how output block is implemented to show list. To display list you can directly use variable name in the value to show the array contents.
output "avengers" { value = var.marvel }
Another approach to achieve this is by using a for loop to create a map from the list. In this map, each key-value pair has the same name for both the key and the value. Note I am using { } curly braces for the same.
output "avengers_infinity_wars" { value = { for avenger in var.marvel : avenger => avenger } }
In this final example I am simply using another for loop variation to show the value from list variable, Note I am using [ ] square brackets.
output "avengers_secret_wars" { value = [ for avenger in var.marvel : avenger ] }
Below is the entire script which you can download Terraform_for_each_list_resources_and_output.tf here or it is also available on the github.com.
variable "marvel" { type = list(any) default = ["IronMan","Thor","Hulk","HawkEye","SpiderMan"] } resource "null_resource" "avengers_captainmarvel" { for_each = toset(var.marvel) provisioner "local-exec" { command = "echo ${each.value} is an Avenger!" } } resource "null_resource" "avengers_blackwidow" { for_each = { for avenger in var.marvel : avenger => avenger } provisioner "local-exec" { command = "echo ${each.value} is an Avenger!" } } resource "null_resource" "avengers_scarletwitch" { count = length(var.marvel) provisioner "local-exec" { command = "echo ${var.marvel[count.index]} is an Avenger!" } } output "avengers" { value = var.marvel } output "avengers_infinity_wars" { value = { for avenger in var.marvel : avenger => avenger } } output "avengers_endgame" { value = toset(var.marvel) } output "avengers_secret_wars" { value = [ for avenger in var.marvel : avenger ] }
In the Below is the output after running terraform apply command. Check and verify how it shows the output for resources and output block.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 |
terraform apply --auto-approve Terraform used the selected providers to generate the following execution plan. Resource actions are indicated with the following symbols: + create Terraform will perform the following actions: # null_resource.avengers_blackwidow["HawkEye"] will be created + resource "null_resource" "avengers_blackwidow" { + id = (known after apply) } # null_resource.avengers_blackwidow["Hulk"] will be created + resource "null_resource" "avengers_blackwidow" { + id = (known after apply) } # null_resource.avengers_blackwidow["IronMan"] will be created + resource "null_resource" "avengers_blackwidow" { + id = (known after apply) } # null_resource.avengers_blackwidow["SpiderMan"] will be created + resource "null_resource" "avengers_blackwidow" { + id = (known after apply) } # null_resource.avengers_blackwidow["Thor"] will be created + resource "null_resource" "avengers_blackwidow" { + id = (known after apply) } # null_resource.avengers_captainmarvel["HawkEye"] will be created + resource "null_resource" "avengers_captainmarvel" { + id = (known after apply) } # null_resource.avengers_captainmarvel["Hulk"] will be created + resource "null_resource" "avengers_captainmarvel" { + id = (known after apply) } # null_resource.avengers_captainmarvel["IronMan"] will be created + resource "null_resource" "avengers_captainmarvel" { + id = (known after apply) } # null_resource.avengers_captainmarvel["SpiderMan"] will be created + resource "null_resource" "avengers_captainmarvel" { + id = (known after apply) } # null_resource.avengers_captainmarvel["Thor"] will be created + resource "null_resource" "avengers_captainmarvel" { + id = (known after apply) } # null_resource.avengers_scarletwitch[0] will be created + resource "null_resource" "avengers_scarletwitch" { + id = (known after apply) } # null_resource.avengers_scarletwitch[1] will be created + resource "null_resource" "avengers_scarletwitch" { + id = (known after apply) } # null_resource.avengers_scarletwitch[2] will be created + resource "null_resource" "avengers_scarletwitch" { + id = (known after apply) } # null_resource.avengers_scarletwitch[3] will be created + resource "null_resource" "avengers_scarletwitch" { + id = (known after apply) } # null_resource.avengers_scarletwitch[4] will be created + resource "null_resource" "avengers_scarletwitch" { + id = (known after apply) } Plan: 15 to add, 0 to change, 0 to destroy. Changes to Outputs: + avengers = [ + "IronMan", + "Thor", + "Hulk", + "HawkEye", + "SpiderMan", ] + avengers_endgame = [ + "HawkEye", + "Hulk", + "IronMan", + "SpiderMan", + "Thor", ] + avengers_infinity_wars = { + HawkEye = "HawkEye" + Hulk = "Hulk" + IronMan = "IronMan" + SpiderMan = "SpiderMan" + Thor = "Thor" } + avengers_secret_wars = [ + "IronMan", + "Thor", + "Hulk", + "HawkEye", + "SpiderMan", ] null_resource.avengers_captainmarvel["HawkEye"]: Creating... null_resource.avengers_captainmarvel["Hulk"]: Creating... null_resource.avengers_blackwidow["HawkEye"]: Creating... null_resource.avengers_blackwidow["IronMan"]: Creating... null_resource.avengers_blackwidow["Hulk"]: Creating... null_resource.avengers_scarletwitch[2]: Creating... null_resource.avengers_captainmarvel["IronMan"]: Creating... null_resource.avengers_blackwidow["HawkEye"]: Provisioning with 'local-exec'... null_resource.avengers_captainmarvel["Hulk"]: Provisioning with 'local-exec'... null_resource.avengers_captainmarvel["SpiderMan"]: Creating... null_resource.avengers_blackwidow["SpiderMan"]: Creating... null_resource.avengers_blackwidow["Thor"]: Creating... null_resource.avengers_scarletwitch[2]: Provisioning with 'local-exec'... null_resource.avengers_captainmarvel["IronMan"]: Provisioning with 'local-exec'... null_resource.avengers_blackwidow["IronMan"]: Provisioning with 'local-exec'... null_resource.avengers_captainmarvel["SpiderMan"]: Provisioning with 'local-exec'... null_resource.avengers_scarletwitch[2] (local-exec): Executing: ["cmd" "/C" "echo Hulk is an Avenger!"] null_resource.avengers_blackwidow["SpiderMan"]: Provisioning with 'local-exec'... null_resource.avengers_captainmarvel["IronMan"] (local-exec): Executing: ["cmd" "/C" "echo IronMan is an Avenger!"] null_resource.avengers_captainmarvel["SpiderMan"] (local-exec): Executing: ["cmd" "/C" "echo SpiderMan is an Avenger!"] null_resource.avengers_blackwidow["Hulk"]: Provisioning with 'local-exec'... null_resource.avengers_blackwidow["SpiderMan"] (local-exec): Executing: ["cmd" "/C" "echo SpiderMan is an Avenger!"] null_resource.avengers_blackwidow["Thor"]: Provisioning with 'local-exec'... null_resource.avengers_captainmarvel["Hulk"] (local-exec): Executing: ["cmd" "/C" "echo Hulk is an Avenger!"] null_resource.avengers_blackwidow["Thor"] (local-exec): Executing: ["cmd" "/C" "echo Thor is an Avenger!"] null_resource.avengers_blackwidow["HawkEye"] (local-exec): Executing: ["cmd" "/C" "echo HawkEye is an Avenger!"] null_resource.avengers_captainmarvel["HawkEye"]: Provisioning with 'local-exec'... null_resource.avengers_blackwidow["IronMan"] (local-exec): Executing: ["cmd" "/C" "echo IronMan is an Avenger!"] null_resource.avengers_blackwidow["Hulk"] (local-exec): Executing: ["cmd" "/C" "echo Hulk is an Avenger!"] null_resource.avengers_captainmarvel["HawkEye"] (local-exec): Executing: ["cmd" "/C" "echo HawkEye is an Avenger!"] null_resource.avengers_scarletwitch[2] (local-exec): Hulk is an Avenger! null_resource.avengers_captainmarvel["SpiderMan"] (local-exec): SpiderMan is an Avenger! null_resource.avengers_captainmarvel["SpiderMan"]: Creation complete after 0s [id=9192055606425142333] null_resource.avengers_scarletwitch[2]: Creation complete after 0s [id=7063158102767413277] null_resource.avengers_captainmarvel["Hulk"] (local-exec): Hulk is an Avenger! null_resource.avengers_scarletwitch[3]: Creating... null_resource.avengers_captainmarvel["Thor"]: Creating... null_resource.avengers_captainmarvel["Hulk"]: Creation complete after 0s [id=7770242689606045898] null_resource.avengers_scarletwitch[3]: Provisioning with 'local-exec'... null_resource.avengers_scarletwitch[3] (local-exec): Executing: ["cmd" "/C" "echo HawkEye is an Avenger!"] null_resource.avengers_captainmarvel["IronMan"] (local-exec): IronMan is an Avenger! null_resource.avengers_captainmarvel["IronMan"]: Creation complete after 0s [id=1981800038228562201] null_resource.avengers_captainmarvel["Thor"]: Provisioning with 'local-exec'... null_resource.avengers_captainmarvel["Thor"] (local-exec): Executing: ["cmd" "/C" "echo Thor is an Avenger!"] null_resource.avengers_scarletwitch[4]: Creating... null_resource.avengers_blackwidow["SpiderMan"] (local-exec): SpiderMan is an Avenger! null_resource.avengers_scarletwitch[1]: Creating... null_resource.avengers_scarletwitch[4]: Provisioning with 'local-exec'... null_resource.avengers_scarletwitch[4] (local-exec): Executing: ["cmd" "/C" "echo SpiderMan is an Avenger!"] null_resource.avengers_scarletwitch[1]: Provisioning with 'local-exec'... null_resource.avengers_blackwidow["SpiderMan"]: Creation complete after 0s [id=5302315061282559139] null_resource.avengers_scarletwitch[1] (local-exec): Executing: ["cmd" "/C" "echo Thor is an Avenger!"] null_resource.avengers_blackwidow["Thor"] (local-exec): Thor is an Avenger! null_resource.avengers_blackwidow["Thor"]: Creation complete after 0s [id=845785058948536104] null_resource.avengers_scarletwitch[0]: Creating... null_resource.avengers_scarletwitch[0]: Provisioning with 'local-exec'... null_resource.avengers_blackwidow["HawkEye"] (local-exec): HawkEye is an Avenger! null_resource.avengers_scarletwitch[0] (local-exec): Executing: ["cmd" "/C" "echo IronMan is an Avenger!"] null_resource.avengers_blackwidow["HawkEye"]: Creation complete after 0s [id=7106059011530237974] null_resource.avengers_blackwidow["IronMan"] (local-exec): IronMan is an Avenger! null_resource.avengers_blackwidow["IronMan"]: Creation complete after 0s [id=865390357854072773] null_resource.avengers_blackwidow["Hulk"] (local-exec): Hulk is an Avenger! null_resource.avengers_blackwidow["Hulk"]: Creation complete after 0s [id=6432483903170596779] null_resource.avengers_captainmarvel["HawkEye"] (local-exec): HawkEye is an Avenger! null_resource.avengers_captainmarvel["HawkEye"]: Creation complete after 0s [id=3649154194512024566] null_resource.avengers_scarletwitch[3] (local-exec): HawkEye is an Avenger! null_resource.avengers_scarletwitch[3]: Creation complete after 0s [id=2121556317005986060] null_resource.avengers_captainmarvel["Thor"] (local-exec): Thor is an Avenger! null_resource.avengers_captainmarvel["Thor"]: Creation complete after 0s [id=381719455332942953] null_resource.avengers_scarletwitch[1] (local-exec): Thor is an Avenger! null_resource.avengers_scarletwitch[1]: Creation complete after 0s [id=6117933928361479405] null_resource.avengers_scarletwitch[4] (local-exec): SpiderMan is an Avenger! null_resource.avengers_scarletwitch[4]: Creation complete after 0s [id=5375947507644832841] null_resource.avengers_scarletwitch[0] (local-exec): IronMan is an Avenger! null_resource.avengers_scarletwitch[0]: Creation complete after 0s [id=288149830994279046] Apply complete! Resources: 15 added, 0 changed, 0 destroyed. Outputs: avengers = tolist([ "IronMan", "Thor", "Hulk", "HawkEye", "SpiderMan", ]) avengers_endgame = toset([ "HawkEye", "Hulk", "IronMan", "SpiderMan", "Thor", ]) avengers_infinity_wars = { "HawkEye" = "HawkEye" "Hulk" = "Hulk" "IronMan" = "IronMan" "SpiderMan" = "SpiderMan" "Thor" = "Thor" } avengers_secret_wars = [ "IronMan", "Thor", "Hulk", "HawkEye", "SpiderMan", ] |
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