write_all

Concatenates one field from all input events into a byte stream.

write_all field

Description

The write_all operator takes one field selector and appends the field’s values in input order. It accepts fields of type blob and string.

For blob fields, write_all appends the bytes verbatim. For string fields, it appends the existing string bytes without adding separators or escaping.

The operator skips null values and events where the selected field is missing. It emits no bytes if all values are skipped.

Examples

Write strings without separators

from {data: "hello"}, {data: " "}, {data: "world"}
to_stdout {
  write_all data
}

hello world

Copy a binary file

Use read_all with binary=true to read a file into a blob field, then write that field back as raw bytes.

from_file "/tmp/report.pdf" {
  read_all binary=true
}
to_file "/tmp/report-copy.pdf" {
  write_all data
}

Write a nested field

from {payload: {data: b"foo"}}, {payload: {data: b"bar"}}
to_file "/tmp/payload.bin" {
  write_all payload.data
}