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log

This document provides an overview of the commands and options available under buck2 log.

buck2 log​

Commands for interacting with buck2 logs

Usage: buck2 log <COMMAND>

Subcommands:​

  • what-ran: Output everything Buck2 ran from selected invocation
  • what-failed: Outputs every command that failed in the selected invocation
  • path: Output the path to the selected log
  • show: Outputs the log in JSON format from selected invocation
  • cmd: Show buck command line arguments from selected invocation
  • what-up: Show the spans that were open when the log ended
  • what-materialized: Outputs materializations from selected invocation
  • what-uploaded: Outputs stats about uploads to RE from the selected invocation
  • critical-path: Show the critical path for a selected build
  • replay: Replay an event log
  • show-user: Converts the event log from a selected invocation into a user event log, in JSONL format
  • summary: Outputs high level statistics about the build
  • diff: Subcommands for diff'ing two buck2 commands
  • external-configs: Display the values and origins of external configs for a selected command

buck2 log what-ran​

Output everything Buck2 ran from selected invocation.

The output is presented as a series of tab-delimited records with the following structure:

The reason for executing a given command. That's either to build or to test.

The identity of this command. This will include the target that ran required it.

The executor for this command. This will either be RE or local.

Details to reproduce it. For RE, that's the action digest. For local, the command.

To reproduce an action that ran on RE, use the following command then follow the instructions. The DIGEST is of the form hash:size.

frecli cas download-action DIGEST

To reproduce an action that ran locally, make sure your working directory is the project root (if unsure, use buck2 root --kind project to find it), then run the command. The command is already shell-quoted.

Usage: buck2 log what-ran [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

  • --format <OUTPUT> Which output format to use for this command

    • Default value: tabulated
    • Possible values:
      • tabulated
      • json
      • csv

  • --emit-cache-queries

  • --skip-cache-hits

  • --skip-remote-executions

  • --skip-local-executions

  • --filter-category <FILTER_CATEGORY> Regular expression to filter commands by given action category (i.e. type of of actions that are similar but operate on different inputs, such as invocations of a C++ compiler (whose category would be cxx_compile)). Matches by full string

  • --failed Show only commands that failed

  • --incomplete Show only commands that were not completed. That is command were running if buck2 process was killed, or command currently running if buck2 is running build now

  • --show-std-err Show also std_err from commands that are run. If the command fails before completing, we display "<command did not finish executing>". If it finishes but there is no error, we display "<stderr is empty>". Otherwise, std_err is shown. For JSON, we show raw values and null for non-completion

  • --omit-empty-std-err Omit commands if their std_err is empty

buck2 log what-failed​

Outputs every command that failed in the selected invocation.

Look at the help for what-ran to understand the output format.

Usage: buck2 log what-failed [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

  • --format <OUTPUT> Which output format to use for this command

    • Default value: tabulated
    • Possible values:
      • tabulated
      • json
      • csv

  • --emit-cache-queries

  • --skip-cache-hits

  • --skip-remote-executions

  • --skip-local-executions

  • --filter-category <FILTER_CATEGORY> Regular expression to filter commands by given action category (i.e. type of of actions that are similar but operate on different inputs, such as invocations of a C++ compiler (whose category would be cxx_compile)). Matches by full string

buck2 log path​

Output the path to the selected log

Usage: buck2 log path [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

  • --all List all the logs

buck2 log show​

Outputs the log in JSON format from selected invocation

Usage: buck2 log show [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

buck2 log cmd​

Show buck command line arguments from selected invocation.

This command output is not machine readable. Robots, please use buck2 log show.

Usage: buck2 log cmd [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

  • --expand Show @-expanded command line arguments instead of the original command line

buck2 log what-up​

Show the spans that were open when the log ended

Usage: buck2 log what-up [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

  • --after <NUMBER> Print the actions that where open after certain amount of milliseconds

buck2 log what-materialized​

Outputs materializations from selected invocation.

The output is a tab-separated list containing the path, the materialization method, the file count, and the total size (after decompression).

Usage: buck2 log what-materialized [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

  • -s, --sort-by-size Sort the output by total bytes in ascending order

  • --aggregate-by-ext Aggregates the output by file extension

  • --format <OUTPUT> Which output format to use for this command

    • Default value: tabulated
    • Possible values:
      • tabulated
      • json
      • csv

buck2 log what-uploaded​

Outputs stats about uploads to RE from the selected invocation

Usage: buck2 log what-uploaded [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

  • --format <OUTPUT> Which output format to use for this command

    • Default value: tabulated
    • Possible values:
      • tabulated
      • json
      • csv

  • --aggregate-by-ext Aggregates the output by file extension

buck2 log critical-path​

Show the critical path for a selected build.

This produces tab-delimited output listing every node on the critical path.

It includes the kind of node, its name, category and identifier, as well as total duration (runtime of this node), user duration (duration the user can improve) and potential improvement before this node stops being on the critical path.

All durations are in microseconds.

Usage: buck2 log critical-path [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

  • --format <FORMAT> Which output format to use for this command

    • Default value: tabulated
    • Possible values:
      • tabulated
      • json
      • csv

buck2 log replay​

Replay an event log.

This command allows visualizing an existing event log in a Superconsole.

Usage: buck2 log replay [OPTIONS] [PATH] [OVERRIDE_ARGS]...

Arguments:​

  • <PATH> A path to an event-log file to read from

  • <OVERRIDE_ARGS> Override the arguments

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

  • --speed <NUMBER> Control the playback speed using a float (i.e. 0.5, 2, etc)

  • --preload Preload the event log. This is typically only useful for benchmarking

  • --console <super|simple|...> Which console to use for this command

    • Default value: auto
    • Possible values:
      • auto
      • none
      • simple
      • simplenotty
      • simpletty
      • super

  • --ui <UI> Configure additional superconsole ui components.

    Accepts a comma-separated list of superconsole components to add. Possible values are:

    dice - shows information about evaluated dice nodes debugevents - shows information about the flow of events from buckd

    These components can be turned on/off interactively. Press 'h' for help when superconsole is active.

    • Possible values:
      • dice
      • debugevents
      • io: I/O panel
      • re: RE panel

  • --no-interactive-console Disable console interactions

buck2 log show-user​

Converts the event log from a selected invocation into a user event log, in JSONL format

Usage: buck2 log show-user [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

buck2 log summary​

Outputs high level statistics about the build

Usage: buck2 log summary [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

buck2 log diff​

Subcommands for diff'ing two buck2 commands

Usage: buck2 log diff <COMMAND>

Subcommands:​

  • action-divergence: Identifies the first divergent action between two builds. Divergence is identified by the same action having differing outputs. Useful for identifying non-determinism
  • external-configs: Identifies the diff between external buckconfigs between two commands

buck2 log diff action-divergence​

Identifies the first divergent action between two builds. Divergence is identified by the same action having differing outputs. Useful for identifying non-determinism

Usage: buck2 log diff action-divergence <--path1 <PATH1>|--trace-id1 <TRACE_ID1>|--recent1 <NUMBER>> <--path2 <PATH2>|--trace-id2 <TRACE_ID2>|--recent2 <NUMBER>>

Options:​

  • --path1 <PATH1> A path to an event-log file of the first command

  • --trace-id1 <TRACE_ID1> Trace id of the first command

  • --recent1 <NUMBER> Open the event-log file from a recent command for the first command

  • --path2 <PATH2> A path to an event-log file of the second command

  • --trace-id2 <TRACE_ID2> Trace id of the second command

  • --recent2 <NUMBER> Open the event-log file from a recent command for the second command

buck2 log diff external-configs​

Identifies the diff between external buckconfigs between two commands

Usage: buck2 log diff external-configs <--path1 <PATH1>|--trace-id1 <TRACE_ID1>|--recent1 <NUMBER>> <--path2 <PATH2>|--trace-id2 <TRACE_ID2>|--recent2 <NUMBER>>

Options:​

  • --path1 <PATH1> A path to an event-log file of the first command

  • --trace-id1 <TRACE_ID1> Trace id of the first command

  • --recent1 <NUMBER> Open the event-log file from a recent command for the first command

  • --path2 <PATH2> A path to an event-log file of the second command

  • --trace-id2 <TRACE_ID2> Trace id of the second command

  • --recent2 <NUMBER> Open the event-log file from a recent command for the second command

buck2 log external-configs​

Display the values and origins of external configs for a selected command.

Buckconfigs are computed by joining together values from various inputs (repo, well-known directories, CLI flags). Each of these is logged in the given order, with later components overriding earlier ones. For config files originating from the repo (i.e. project-relative paths), except .buckconfig.local, we log the path, not the actual values.

Usage: buck2 log external-configs [OPTIONS] [PATH]

Arguments:​

  • <PATH> A path to an event-log file to read from

Options:​

  • --recent <NUMBER> Open the event-log file from a recent command

  • --trace-id <ID> Show log by trace id

  • --allow-remote This option does nothing

  • --no-remote Do not allow downloading the log from manifold if it's not found locally

  • --format <FORMAT> Which output format to use for this command

    • Default value: tabulated
    • Possible values:
      • tabulated
      • json
      • csv