Write a recipe in yocto for a python application
Creating Recipes for non-available python apps
Since influxdb-python
and pynmea2
are not available as standard python recipes, I began by creating recipes for them using devtool
.
Steps
use
devtool
to add theinfluxdb-python
devtool add influxdb-python https://github.com/influxdata/influxdb-python/archive/v5.2.0.tar.gz
use
devtool
to add thepynmea2
devtool add pynmea2 https://github.com/Knio/pynmea2/archive/1.7.1.tar.gz
The above mentioned steps creates a folder workspace
in your $BUILD_DIR
and created auto-generated recipes for the repos.
Edit the recipes
devtool edit-recipe influxdb-python
add or check
DEPEND_${PN}
andRDEPENDS_${PN}
to your recipes accordingly. I added all therequirements.txt
forinfluxdb-python
toRDEPENDS_${PN}
viz.RDEPEND_${PN} += "${PYTHON_PN}-modules ${PYTHON_PN}-requests ${PYTHON_PN}-dateutil ${PYTHON_PN}-pytz ${PYTHON_PN}-six"
NOTE: I have not added
pandas
ornumpy
as they aren't relevant for my application.I added
DEPENDS_${PN} = "${PYTHON_PN}-modules
also.
NOTE: Perform the same for
pynmea2
but since it does not have anyrequirements.txt
I addedRDEPENDS_${PN} = "${PYTHON_PN}-modules"
so all major things are available on the target.
Recipe Structure
I followed the meta-python
folder's structure where each of the recipes consists of :
recipe.inc
recipe_version_number.bb
In the influxdb_python.inc
keep all the stuff generated from devtool
viz.
# Recipe created by recipetool# This is the basis of a recipe and may need further editing in order to be fully functional.# (Feel free to remove these comments when editing.)## WARNING: the following LICENSE and LIC_FILES_CHKSUM values are best guesses - it is# your responsibility to verify that the values are complete and correct.LICENSE = "MIT"LIC_FILES_CHKSUM = "file://LICENSE;md5=046523829184aac3703a4c60c0ae2104"HOMEPAGE = "https://github.com/influxdb/influxdb-python"SUMMARY = "InfluxDB client"SRC_URI = "https://github.com/influxdata/influxdb-python/archive/v${PV}.tar.gz"SRC_URI[md5sum] = "105d88695151e241523b31dd1375096e"SRC_URI[sha256sum] = "620de85bcca5207b06ec1565884b6d10b4be01d579a78e08b1e922f453fdac05"DEPENDS_${PN} = "${PYTHON_PN}-modules"RDEPENDS_${PN} = "${PYTHON_PN}-modules ${PYTHON_PN}-requests ${PYTHON_PN}-dateutil ${PYTHON_PN}-pytz ${PYTHON_PN}-six"
In the influxdb_python_5.2.0.bb
I added the following lines:
inherit setuptools3 pypi require influxdb-python.inc
NOTE: I added
setuptools3
since I want my app to be run onpython3.5
. For python2.7 usesetuptools
.
Similarly, I did the same for pynmea2.inc
:
# Recipe created by recipetool# This is the basis of a recipe and may need further editing in order to be fully functional.# (Feel free to remove these comments when editing.)## WARNING: the following LICENSE and LIC_FILES_CHKSUM values are best guesses - it is# your responsibility to verify that the values are complete and correct.LICENSE = "MIT"LIC_FILES_CHKSUM = "file://LICENSE;md5=bb5e173bc54080cb25079199959ba6b6"HOMEPAGE = "https://github.com/Knio/pynmea2"SUMMARY = "Python library for the NMEA 0183 protcol"SRC_URI = "https://github.com/Knio/pynmea2/archive/${PV}.tar.gz"SRC_URI[md5sum] = "a90baf61f4e676bef76099e4bd7c0581"SRC_URI[sha256sum] = "8f8f68623bd2d5dab7f04a9c31813a3f4aa15467db0373cbce6b9b0ae44ca48e"#DEPENDS_${PN} = "${PYTHON_PN}-datetime ${PYTHON_PN}-threading ${PYTHON_PN}-io"DEPENDS_${PN} = "${PYTHON_PN}-modules"# WARNING: the following rdepends are determined through basic analysis of the# python sources, and might not be 100% accurate.RDEPENDS_${PN} = "${PYTHON_PN}-modules"
For pynmea2_1.7.1.bb
:
inherit setuptools3 pypirequire pynmea2.inc
Baking the recipes
You could test them withbitbake -k influxdb-python
and bitbake -k pynmea2
or withdevtool build influxdb-python
and devtool build pynmea2
If you have no errors then you can deploy it on target using:
devtool deploy-target influxdb-python user@machineIP:dest_folder
Checks
You can check by firing the python shell
# python3 >> import influxdb-python >> import pyserial
if the import is throws no missing modules error then it is success!!
Final steps
You can undeploy the modules:
devtool undeploy-target recipe_name [address of target]
send the recipes to you custom meta layer
devtool finish recipe_name ../meta-custom
NOTE: If you are using
krogoth
or lower the you will have to move your recipes to you meta layer manually
- Now include these recipes in your
conf/local.conf
withIMAGE_INSTALL_append = " influxdb-python pynmea2"
andbitbake -k your-image-name
Custom Application
Not tested yet.
But I think I will simple add my app like mentioned in YoctoCookBook Repository for hello-world
with my meta
layer.
NUGGETS
${PYTHON_PN}-modules
is a saviour really. I tried manually added runtime deps and everytime i deployed it on the board there were always some dependencies missing. But adding themodules
solved all the missing deps issue in an instance.I am not sure when to use
DEPENDS_${PN}
but I assume most python applications depend on the basicpython-modules
hence I added them.NOT A YOCTO EXPERT but this is just my finding in the last 2 weeks. There is a lack of proper examples for Python in Yocto. hope this helps someone.