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Lam Language

Lam is a DSL for data transformation.

It runs on the Laminar platform and is used to transform data when flows are executed.

Our language documentation is currently under construction. Please check back soon for a full language reference.

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Example

In this example, we will transform the following JSON:

{
  "message": "Hello lam",
  "foo": "delete me",
  "http_status": "200"
}

Into the following JSON:

{
  "message": "Hello lam",
  "timestamp": "2021-01-01T00:00:00Z",
  "http_status_code": 200,
  "status": "success"
}

Using the following lam script:

# Remove some fields
del(.foo)

# Add a timestamp
.timestamp = now()

# Parse HTTP status code into local variable
http_status_code = parse_int!(.http_status)
del(.http_status)

# Add status
if http_status_code >= 200 && http_status_code <= 299 {
    .status = "success"
} else {
    .status = "error"
}

Here’s what’s happening:

• del(.foo) removes the foo field from the input.
• .timestamp = now() adds a new field called timestamp with the current time.
• http_status_code = parse_int!(.http_status) parses the http_status field into a local variable called http_status_code.
• del(.http_status) removes the http_status field from the input.
• if http_status_code >= 200 && http_status_code <= 299 { starts an if statement.
• .status = "success" adds a new field called status with the value success.
• } else { starts the else block.
• .status = "error" adds a new field called status with the value error.
• } ends the if statement.

With the input our script will produce the following output:

{
  "message": "Hello lam",
  "timestamp": "2021-01-01T00:00:00Z",
  "http_status_code": 200,
  "status": "success"
}

We can easily modify the script to produce different output. For example, we can change the status field to be a boolean called succeeded:

# Remove some fields
del(.foo)

# Add a timestamp
.timestamp = now()

# Parse HTTP status code into local variable
http_status_code = parse_int!(.http_status)
del(.http_status)

# Add succeeded
if http_status_code >= 200 && http_status_code <= 299 {
    .succeeded = true
} else {
    .succeeded = false
}

This will produce the following output:

{
  "message": "Hello lam",
  "timestamp": "2021-01-01T00:00:00Z",
  "http_status_code": 200,
  "status": true
}

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