#10372 bug: meltano run console output hides block failure reason ("Block run completed" with no error) Issue created by visch (Ai Generated issue): Not sure how you all feel about these, but it does a much better job than I will giving all the details Meltano Version 4.4.0 (also present on

main

) Python Version 3.14 Bug scope CLI (options, error messages, logging, etc.) Operating System Linux Description When a block in

meltano run

fails, the default console output doesn't say why:

[error    ] meltano      Block run completed
[info     ] meltano      Run completed

The exit code is 1, but the output gives no reason.

meltano invoke

on the same command shows the error. The failure reason is attached to the log event.

cli/run.py

logs it as structured keys: logger.error( "Block run completed", set_number=idx, block_type=blk_name, success=False, err=err.args[0] if err.args else err.class.name, exit_codes=err.exitcodes, duration_seconds=round(block_duration, 3), ) But

MeltanoConsoleRenderer.__call__

(

core/logging/renderers.py

) drops every key that isn't in

default_keys

, unless

all_keys

or

include_keys

is set: elif not self._all_keys: event_dict = {k: v for k, v in event_dict.items() if k in self.default_keys}

err

and

exit_codes

aren't in

default_keys

, so the reason is dropped.

status

on the final "Run completed" event is dropped the same way, so a failed run and a successful one look alike apart from the level. Steps to reproduce # meltano.yml version: 1 default_environment: dev environments: - name: dev plugins: utilities: - name: my-utility namespace: my_utility executable: echo $ meltano run my-utility:hello [error ] meltano Block run completed [info ] meltano Run completed $ echo $? 1 $ meltano invoke my-utility:hello UnknownCommandError: Command 'hello' could not be found. Utility 'my-utility' does not define any commands. The information is there with `--log-format=json`: {"block_type": "InvokerCommand", "success": false, "err": "Cannot start plugin: Command 'hello' could not be found. Utility 'my-utility' does not define any commands.", "exit_codes": {}, "event": "Block run completed", "level": "error", ...} Workaround A project

logging.yaml

that passes

include_keys

to the console formatter shows the reason: version: 1 disable_existing_loggers: false formatters: console: (): meltano.core.logging.console_log_formatter colors: true include_keys: [err, exit_codes, status] handlers: console: class: logging.StreamHandler level: INFO formatter: console stream: ext://sys.stderr root: level: INFO handlers: [console]

[error    ] meltano      Block run completed            err="Cannot start plugin: Command 'hello' could not be found. Utility 'my-utility' does not define any commands." exit_codes={}
[info     ] meltano      Run completed                  status=failure

A custom

logging.yaml

replaces the default logging setup completely, so

--log-level

and

--log-format

stop working. Users shouldn't need one to find out why a run failed. Expected behavior The default console output of a failed

meltano run

should include the failure reason. Suggested fix Add

err

,

exit_codes

and

status

to

MeltanoConsoleRenderer.default_keys

. This is the same change the workaround makes, applied by default. The trade-off is that successful blocks also print

err=None

. If that's unwanted,

run.py

could leave out

err

on success, or put the reason in the event text on failure, e.g.

"Block run failed: {err}"

. Related: #7372 (closed as stale). It covers

meltano run

output being harder to understand than

meltano invoke

. meltano/meltano