`s3_presign_url`

Generate a presigned URL (or presigned DELETE/HEAD/PUT URL) for S3 operations.

Parameters

bucketstringrequireddefault env S3_BUCKET: Bucket name used for signing.
keystringrequired: Object key to access.
methodstringdefault "GET": One of GET, PUT, HEAD, DELETE.
expires_innumberdefault 3600: URL validity in seconds (1..604800).
content_typestringdefault "application/octet-stream": Optional content type for presigned PUT.
content_lengthnumber: Optional content length hint for presigned PUT.
regionstringdefault S3_REGION / AWS_REGION: Explicit AWS/S3 region override.
endpoint_urlstringdefault env AWS_ENDPOINT_URL: Optional custom S3-compatible endpoint.
force_path_stylebooldefault false: Force path-style bucket addressing.
output_keystringdefault "s3": Prefix for context output keys.

Context Output

{output_key}_bucket — Bucket used for signing.
{output_key}_key — Object key used for signing.
{output_key}_method — HTTP method used.
{output_key}_expires_in — Expiration window in seconds.
{output_key}_url — Presigned URL string.
{output_key}_headers — Required headers for signing (if any).
{output_key}_success — true on success.

Example

local flow = Flow.new("s3_presign")

flow:step("setup", nodes.s3_put_object({
    bucket = env("S3_BUCKET"),
    key = "raw/temp/demo/presign.txt",
    content = "Hello from presign flow",
    output_key = "upload"
}))

flow:step("presign", nodes.s3_presign_url({
    bucket = env("S3_BUCKET"),
    key = "raw/temp/demo/presign.txt",
    method = "GET",
    expires_in = 600,
    output_key = "presigned"
})):depends_on("setup")

flow:step("read", nodes.http_get({
    url = "${ctx.presigned_url}",
    output_key = "download"
})):depends_on("presign")

flow:step("cleanup", nodes.s3_delete_object({
    bucket = env("S3_BUCKET"),
    key = "raw/temp/demo/presign.txt",
    output_key = "deleted"
})):depends_on("read")

flow:step("log", nodes.log({
    message = "Presigned URL generated (${ctx.presigned_expires_in}s): ${ctx.presigned_url}"
})):depends_on("cleanup")

return flow