File functions (file, templatefile) in Terraform - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to read the contents of a file named "config.txt".

Terraform

content = file("[1]")

Drag options to blanks, or click blank then click option'

Atemplate.tpl

Bconfig.txt

Cdata.txt

Dconfig.json

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong file name.

Confusing file with templatefile.

The file function reads the entire content of the specified file. Here, the file name is "config.txt".

2fill in blank

medium

Complete the code to load a template file named "server.tpl".

Terraform

template_content = templatefile("[1]", { port = 8080 })

Drag options to blanks, or click blank then click option'

Adata.json

Bconfig.txt

Cserver.tpl

Dmain.tf

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-template file with templatefile.

Misspelling the file name.

The templatefile function loads a template file. Here, the file is "server.tpl".

3fill in blank

hard

Fix the error in the code to correctly read a file named "data.json".

Terraform

data = file([1])

Drag options to blanks, or click blank then click option'

A"data.json"

Bdata.json

Cdata

D'data.json'

Attempts:

3 left

💡 Hint

Common Mistakes

Passing the file name without quotes.

Using single quotes instead of double quotes.

The file function requires the file path as a quoted string. So, use double quotes around "data.json".

4fill in blank

hard

Fill both blanks to read a template file "app.tpl" and pass the variable "version" with value "1.2.3".

Terraform

app_config = templatefile("[1]", { [2] = "1.2.3" })

Drag options to blanks, or click blank then click option'

Aapp.tpl

Bversion

Cconfig.tpl

Drelease

Attempts:

3 left

💡 Hint

Common Mistakes

Using the wrong file name.

Using incorrect variable names.

The first blank is the template file name "app.tpl". The second blank is the variable name "version" passed to the template.

5fill in blank

hard

Fill all three blanks to read a file "settings.conf", read a template "deploy.tpl", and pass variable "env" with value "prod".

Terraform

settings = file("[1]")
deploy_script = templatefile("[2]", { [3] = "prod" })

Drag options to blanks, or click blank then click option'

Asettings.conf

Bdeploy.tpl

Cenv

Dconfig.json

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing file names between file and templatefile.

Using wrong variable names.

The first blank is the file name "settings.conf" for the file function. The second blank is the template file "deploy.tpl". The third blank is the variable name "env" passed to the template.

Practice

1. What does the Terraform function file() do?

easy

A. Writes content to a file

B. Reads a file and replaces variables inside it

C. Reads the entire content of a file as plain text

D. Deletes a file from the system

Solution

1. Step 1: Understand the purpose of file()

   The file() function reads the content of a file and returns it as plain text without any processing.

2. Step 2: Compare with other functions

   templatefile() replaces variables inside a file, but file() just reads raw content.

3. Final Answer:

   Reads the entire content of a file as plain text -> Option C

4. Quick Check:

   file() reads file content [OK]

Hint: file() just reads text, no variable replacement [OK]

Common Mistakes:

• Confusing file() with templatefile()
• Thinking file() modifies file content
• Assuming file() writes to files

2. Which of the following is the correct syntax to use templatefile() in Terraform?

easy

A. templatefile("path/to/file.tpl", { var1 = "value1" })

B. templatefile(path = "file.tpl", vars = { var1 = "value1" })

C. templatefile("file.tpl", var1 = "value1")

D. templatefile("file.tpl")

Solution

1. Step 1: Recall the correct function signature

   templatefile() requires two arguments: the file path as a string and a map of variables.

2. Step 2: Match the syntax

   templatefile("path/to/file.tpl", { var1 = "value1" }) correctly passes the file path and a map with variable assignments. Other options either use wrong parameter names or omit the variables map.

3. Final Answer:

   templatefile("path/to/file.tpl", { var1 = "value1" }) -> Option A

4. Quick Check:

   templatefile(path, vars map) syntax [OK]

Hint: templatefile needs path string and vars map [OK]

Common Mistakes:

• Using named parameters instead of positional
• Passing variables outside a map
• Omitting the variables map argument

3. Given the file message.tpl with content:

Hello, ${name}!

What is the output of this Terraform expression?
templatefile("message.tpl", { name = "Alice" })

medium

A. Hello, Alice!

B. Hello, ${name}!

C. templatefile("message.tpl", { name = "Alice" })

D. Error: variable 'name' not found

Solution

1. Step 1: Understand templatefile variable replacement

   The templatefile() function reads the file and replaces variables like ${name} with the provided value.

2. Step 2: Apply the variable substitution

   Since name is set to "Alice", the output becomes "Hello, Alice!".

3. Final Answer:

   Hello, Alice! -> Option A

4. Quick Check:

   templatefile replaces variables [OK]

Hint: templatefile replaces ${var} with values from map [OK]

Common Mistakes:

• Expecting raw template text output
• Confusing file() with templatefile() output
• Missing variable in map causing error

4. You wrote this Terraform code:

output "config" {
  value = templatefile("config.tpl", { env = "prod" })
}

But Terraform shows an error: File not found: config.tpl. What is the likely cause?

medium

A. The file config.tpl is empty

B. The variable env is missing in the map

C. templatefile() cannot be used in output blocks

D. The file config.tpl does not exist in the working directory

Solution

1. Step 1: Analyze the error message

   The error says "File not found", which means Terraform cannot locate the file config.tpl.

2. Step 2: Check file existence and path

   Most likely, the file is missing or the path is incorrect. Variables missing or empty files do not cause this error.

3. Final Answer:

   The file config.tpl does not exist in the working directory -> Option D

4. Quick Check:

   File not found error means missing file [OK]

Hint: Check file path and existence if 'File not found' error [OK]

Common Mistakes:

• Assuming variable map causes file not found
• Thinking templatefile() is invalid in output
• Ignoring file path correctness

5. You want to create a Terraform output that reads a JSON file data.json and replaces a placeholder ${region} inside it with your variable var.region. Which approach is best?

hard

A. Use file() to read data.json and then use replace() to substitute ${region}

B. Use templatefile() with data.json and pass { region = var.region } as variables

C. Use file() only, since it automatically replaces variables

D. Use templatefile() but pass an empty map for variables

Solution

1. Step 1: Understand the difference between file() and templatefile()

   file() reads raw content without variable substitution. templatefile() reads and replaces variables inside the file.

2. Step 2: Choose the correct function and usage

   Since you want to replace ${region} with var.region, templatefile() with a variables map is the best choice.

3. Final Answer:

   Use templatefile() with data.json and pass { region = var.region } as variables -> Option B

4. Quick Check:

   templatefile() replaces placeholders with variables [OK]

Hint: Use templatefile() to replace placeholders with variables [OK]

Common Mistakes:

• Expecting file() to replace variables
• Passing empty variable map to templatefile()
• Using replace() manually instead of templatefile()