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message when deleted inside retry processor, does not apply

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
45/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
go, postgresql
Domain
backend, databases

Research direction

Reproduce the supplied pipeline with the retry processor and sql_insert output, then trace how a deleted message moves from the retry processors to the output. Confirm the behavior against the PostgreSQL example; done means a message deleted inside retry processing does not cause sql_insert to execute.

Written by the indexing model from the issue text.

Description

Seeing something abnormal with retry processor, if the message was deleted in one of the retry processors and using a sql_insert output, was not expecting execution of sql_insert. But sql_insert fails with a error. Here is a sample pipeline that fails.

input:
  generate:
    interval: 1m
    mapping: |-
      root = { "p1": "test val" }
pipeline:
  processors:
  - retry:
      backoff:
        initial_interval: 500ms
        max_interval: 10s
        max_elapsed_time: 0s
      processors:
        - log:
            message: 'incoming msg ${! content() }'
        - mapping: root = deleted()
output:
  sql_insert:
    driver: postgres
    dsn: postgres://${DB_USER}:${DB_PASSWORD}@${DB_HOST}:5432/${DB_NAME}?sslmode=disable
    conn_max_idle_time: 1m
    table: test_table
    columns:
      - p1
    args_mapping: |
      root = [
        this.p1
      ]
    init_statement:
      CREATE TABLE IF NOT EXISTS test_table (
        p1 varchar
      )

and console output:

INFO incoming msg {"p1":"test_value"}              @service=benthos custom_source=true label="" path=root.pipeline.processors.0.retry.processors.0
INFO Output type sql_insert is now active          @service=benthos label="" path=root.output
ERRO Failed to send message to sql_insert: insert statements must have at least one set of values or select clause  @service=benthos label="" path=root.output
INFO incoming msg {"p1":"test_value"}              @service=benthos custom_source=true label="" path=root.pipeline.processors.0.retry.processors.0
ERRO Failed to send message to sql_insert: insert statements must have at least one set of values or select clause  @service=benthos label="" path=root.output
INFO incoming msg {"p1":"test_value"}              @service=benthos custom_source=true label="" path=root.pipeline.processors.0.retry.processors.0

Could workaround it by deleting message in a pre-processor to sql_insert, like below:

output:
  sql_insert:
    driver: postgres
    dsn: postgres://${DB_USER}:${DB_PASSWORD}@${DB_HOST}:5432/${DB_NAME}?sslmode=disable
    conn_max_idle_time: 1m
    table: test_table
    columns:
      - p1
    args_mapping: |
      root = [
        this.p1
      ]
    init_statement:
      CREATE TABLE IF NOT EXISTS test_table (
        p1 varchar
      )
  processors:
    - mapping: |-
        root = if this == null {
          deleted()
        }
Dominant language
Go
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571
Forks
121
Avg merge
1d 13h
Merged PRs (30d)
15

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