tools/devshell/build-profile

#!/bin/bash
# Copyright 2024 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

#### CATEGORY=Other
### manage build profile configuration

## usage:
##  fx build-profile status
##       Show if system profiling during fx build is enabled or disabled.
##
##  fx build-profile enable
##       Enable system profiling during fx build.
##
##  fx build-profile disable
##       Disable system profiling during fx build.
##
## Build profiles contain information about the state of your system
## resources such as CPU, memory, disk I/O.
## 'vmstat' is one such tool that collects this data.
## Build profile data contains no PII.

set -e

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/lib/vars.sh || exit $?
source "${FUCHSIA_DIR}/tools/devshell/lib/style.sh" || exit $?

readonly BUILD_PROFILE_CONFIG="${FUCHSIA_DIR}/.fx/config/build-profile"
readonly BUILD_PROFILE_CONFIG_OLD="${FUCHSIA_DIR}/.fx-build-profile-config"

function usage {
  fx-command-help
}

function styled-status {
  local enabled="$1"
  local profile_status
  if [[ "$BUILD_PROFILE_ENABLED" -eq 1 ]]; then
    profile_status="enabled"
    color="green"
  else
    profile_status="disabled"
    color="red"
  fi
  style::echo --bold "--${color}" "${profile_status}"
}

fx-standard-switches "$@"
set -- "${FX_ARGV[@]}"

if [[ $# -lt 1 ]]; then
  fx-error Invalid syntax
  fx-command-help
  exit 1
fi

action="$1"
shift
action_args=("$@")

function build-profile-read-config {
  BUILD_PROFILE_ENABLED=0
  if [[ -f "${BUILD_PROFILE_CONFIG_OLD}" ]]; then
    fx-info "Moving ${BUILD_PROFILE_CONFIG_OLD} to new location ${BUILD_PROFILE_CONFIG}.  No further action is necessary."
    mv "${BUILD_PROFILE_CONFIG_OLD}" "${BUILD_PROFILE_CONFIG}"
  fi
  if [[ ! -f "${BUILD_PROFILE_CONFIG}" ]]; then
    return 1
  fi
  source "${BUILD_PROFILE_CONFIG}"
  return 0
}

function build-profile-write-config {
  local enabled="$1"
  local -r tempfile="${BUILD_PROFILE_CONFIG}.tmp"

  cat > "${tempfile}" <<EOF
# Autogenerated config file for 'fx build-profile'.
# Run 'fx help build-profile' for more information.
BUILD_PROFILE_ENABLED=${enabled}
EOF
  # Only rewrite the config file if content has changed
  if ! cmp --silent "${tempfile}" "${BUILD_PROFILE_CONFIG}"
  then mv -f "${tempfile}" "${BUILD_PROFILE_CONFIG}"
  else rm -f "${tempfile}"
  fi
}

# Read config in a way that exit code is preserved but doesn't exit because
# of "set -e" if config file doesn't exist
__successfully_read_config=0
build-profile-read-config || __successfully_read_config="$?"

case "$action" in
  -h|--help)
    usage
    exit 0
    ;;

  status)
    echo "Collection of system profiles during builds is currently $(styled-status "$BUILD_PROFILE_ENABLED") for ${FUCHSIA_DIR}"
    echo "To change it, run: fx build-profile <enable|disable>"
    exit 0
    ;;

  enable)
    if [[ "$BUILD_PROFILE_ENABLED" -eq 1 ]]; then
      echo "System profiling during build is already enabled."
      exit 0
    fi
    BUILD_PROFILE_ENABLED=1
    build-profile-write-config "${BUILD_PROFILE_ENABLED}"
    echo "System profiling during build is enabled at user's request"
    ;;

  disable)
    if [[ "$BUILD_PROFILE_ENABLED" -eq 0 ]]; then
      if [[ "${__successfully_read_config}" -ne 0 ]]; then
        # if profile is already disabled but the config file does not exist or
        # is inconsistent, we rewrite the file before exiting
        build-profile-write-config "${BUILD_PROFILE_ENABLED}"
      fi
      echo "System profiling during build is already disabled."
      exit 0
    fi
    BUILD_PROFILE_ENABLED=0
    build-profile-write-config "${BUILD_PROFILE_ENABLED}"
    echo "System profiling during build is disabled at user's request"
    ;;

  *)
    fx-error Invalid syntax
    fx-command-help
    exit 1
    ;;
esac

echo "System profiling during build is now $(styled-status "$BUILD_PROFILE_ENABLED") for ${FUCHSIA_DIR}"