Advanced Scripting

New in version 3.4.1.

Warning

Advanced Scripting is recommended for Advanced Users and requires Python language knowledge.

We highly recommend to take a look at Dynamic build flags option where you can use any programming language. Also, this option is useful if you need to apply changes to the project before building/uploading process:

  • Macro with the latest VCS revision/tag “on-the-fly”
  • Generate dynamic headers (*.h)
  • Process media content before generating SPIFFS image
  • Make some changes to source code or related libraries

More details Dynamic build flags.

PlatformIO Build System allows to extend build process with the custom extra_scripts using Python interpreter and SCons construction tool. Build and upload flags, targets, toolchains data, and other information are stored in SCons Construction Environments.

Warning

You can not run/debug these scripts directly with Python interpreter. They will be loaded automatically when you processing project environment using platformio run command.

Launch types

There are 2 launch type of extra scripts:

  1. PRE - executes before a main script of Development Platforms
  2. POST - executes after a main script of Development Platforms

Multiple extra scripts are allowed. Please split them via “, ” (comma + space) in the same line or use multi-line values.

For example, Project Configuration File platformio.ini

[env:my_env_1]
platform = ...
; without prefix, POST script
extra_scripts = post_extra_script.py

[env:my_env_2]
platform = ...
extra_scripts = pre:pre_extra_script1.py, pre:pre_extra_script2.py

[env:my_env_3]
platform = ...
extra_scripts =
  pre:pre_extra_script.py
  post:post_extra_script1.py
  post_extra_script2.py

This option can be set by global environment variable PLATFORMIO_EXTRA_SCRIPTS.

Construction Environments

There are 2 built-in construction environments which PlatformIO Build System uses to process a project:

extra_script.py:

Import("env", "projenv")

# access to global construction environment
print env

# access to project construction environment
print projenv

#
# Dump construction environments (for debug purpose)
print env.Dump()
print projenv.Dump()

See examples below how to import construction environments and modify existing data or add new.

Before/Pre and After/Post actions

PlatformIO Build System has rich API that allows to attach different pre-/post actions (hooks) using env.AddPreAction(target, callback) or env.AddPreAction(target, [callback1, callback2, ...]) function. A first argument target can be a name of target that is passed using platformio run --target command, a name of built-in targets (buildprog, size, upload, program, buildfs, uploadfs, uploadfsota) or path to file which PlatformIO processes (ELF, HEX, BIN, OBJ, etc.).

Examples

extra_script.py file is located on the same level as platformio.ini.

platformio.ini:

[env:pre_and_post_hooks]
extra_scripts = post:extra_script.py

extra_script.py:

Import("env", "projenv")

# access to global build environment
print env

# access to project build environment (is used source files in "src" folder)
print projenv

#
# Dump build environment (for debug purpose)
# print env.Dump()
#

#
# Change build flags in runtime
#
env.ProcessUnFlags("-DVECT_TAB_ADDR")
env.Append(CPPDEFINES=("VECT_TAB_ADDR", 0x123456789))

#
# Upload actions
#

def before_upload(source, target, env):
    print "before_upload"
    # do some actions

    # call Node.JS or other script
    env.Execute("node --version")


def after_upload(source, target, env):
    print "after_upload"
    # do some actions

print "Current build targets", map(str, BUILD_TARGETS)

env.AddPreAction("upload", before_upload)
env.AddPostAction("upload", after_upload)

#
# Custom actions when building program/firmware
#

env.AddPreAction("buildprog", callback...)
env.AddPostAction("buildprog", callback...)

#
# Custom actions for specific files/objects
#

env.AddPreAction("$BUILD_DIR/${PROGNAME}.elf", [callback1, callback2,...])
env.AddPostAction("$BUILD_DIR/${PROGNAME}.hex", callback...)

# custom action before building SPIFFS image. For example, compress HTML, etc.
env.AddPreAction("$BUILD_DIR/spiffs.bin", callback...)

# custom action for project's main.cpp
env.AddPostAction("$BUILD_DIR/src/main.cpp.o", callback...)

# Custom HEX from ELF
env.AddPostAction(
    "$BUILD_DIR/${PROGNAME}.elf",
    env.VerboseAction(" ".join([
        "$OBJCOPY", "-O", "ihex", "-R", ".eeprom",
        "$BUILD_DIR/${PROGNAME}.elf", "$BUILD_DIR/${PROGNAME}.hex"
    ]), "Building $BUILD_DIR/${PROGNAME}.hex")
)

Examples

Take a look at the multiple snippets/answers for the user questions:

Custom options in platformio.ini

platformio.ini:

[env:my_env]
platform = ...
extra_scripts = extra_script.py

custom_option1 = value1
custom_option2 = value2

extra_script.py:

from platformio import util

config = util.load_project_config()

value1 = config.get("my_env", "custom_option1")
value2 = config.get("my_env", "custom_option2")

Split C/C++ build flags

platformio.ini:

[env:my_env]
platform = ...
extra_scripts = extra_script.py

extra_script.py (place it near platformio.ini):

Import("env")

# General options that are passed to the C and C++ compilers
env.Append(CCFLAGS=["flag1", "falg2"])

# General options that are passed to the C compiler (C only; not C++).
env.Append(CFLAGS=["flag1", "flag2"])

# General options that are passed to the C++ compiler
env.Append(CXXFLAGS=["flag1", "flag2"])

Extra Linker Flags without -Wl, prefix

Sometimes you need to pass extra flags to GCC linker without Wl,. You could use build_flags option but it will not work. PlatformIO will not parse these flags to LINKFLAGS scope. In this case, simple extra script will help:

platformio.ini:

[env:env_extra_link_flags]
platform = windows_x86
extra_scripts = extra_script.py

extra_script.py (place it near platformio.ini):

Import("env")

#
# Dump build environment (for debug)
# print env.Dump()
#

env.Append(
  LINKFLAGS=[
      "-static",
      "-static-libgcc",
      "-static-libstdc++"
  ]
)

Custom upload tool

You can override default upload command of development platform using extra script. There is the common environment variable UPLOADCMD which PlatformIO Build System will handle when you platformio run -t upload.

Please note that some development platforms can have more than 1 upload command. For example, Atmel AVR has UPLOADHEXCMD (firmware) and UPLOADEEPCMD (EEPROM data).

See examples below:

platformio.ini:

[env:my_custom_upload_tool]
platform = ...
# place it into the root of project or use full path
extra_scripts = extra_script.py
upload_protocol = custom
upload_flags = -arg1 -arg2 -argN

extra_script.py (place it near platformio.ini):

Import("env")

# please keep $SOURCE variable, it will be replaced with a path to firmware

# Generic
env.Replace(
    UPLOADER="executable or path to executable"
    UPLOADCMD="$UPLOADER $UPLOADERFLAGS $SOURCE"
)

# In-line command with arguments
env.Replace(
    UPLOADCMD="executable -arg1 -arg2 $SOURCE"
)

# Python callback
def on_upload(source, target, env):
    print source, target
    firmware_path = str(source[0])
    # do something
    env.Execute("executable arg1 arg2")

env.Replace(UPLOADCMD=on_upload)

Custom firmware/program name

Sometime is useful to have a different firmware/program name in build_dir.

platformio.ini:

[env:env_custom_prog_name]
platform = espressif8266
board = nodemcuv2
framework = arduino
build_flags = -D VERSION=13
extra_scripts = pre:extra_script.py

extra_script.py:

Import("env")

my_flags = env.ParseFlags(env['BUILD_FLAGS'])
defines = {k: v for (k, v) in my_flags.get("CPPDEFINES")}
# print defines

env.Replace(PROGNAME="firmware_%s" % defines.get("VERSION"))

Custom build target

There is a list with built-in targets which could be processed using platformio run --target option. You can create unlimited number of the own targets and declare custom handlers for them.

Let’s create a simple ping target and process it with platformio run --target ping command:

platformio.ini:

[env:env_custom_target]
platform = ...
...
extra_scripts = extra_script.py
custom_ping_host = google.com

extra_script.py:

from platformio import util
from SCons.Script import AlwaysBuild
Import("env")

config = util.load_project_config()
host = config.get("env_custom_target", "custom_ping_host")

def mytarget_callback(*args, **kwargs):
    print "Hello PlatformIO!"
    env.Execute("ping " + host)


AlwaysBuild(env.Alias("ping", "", mytarget_callback))