Success. The file tree depicted at the bottom of this mail is nearly the
smallest, valid BitBake project that prints "Hello, World!" Here's the output:
$ ../BitBake/bin/bitbake a
Parsing recipes: 100%
|#############################################################| Time: 00:00:00
Parsing of 1 .bb files complete (0 cached, 1 parsed). 1 targets, 0 skipped,
0 masked, 0 errors.
NOTE: Resolving any missing task queue dependencies
NOTE: Preparing runqueue
NOTE: Executing RunQueue Tasks
NOTE: Running task 1 of 1 (ID: 0,
/home/pturley/Workspace/Hello/LayerA/a.bb, do_build)
NOTE: package None: task do_build: Started
Hello, World!
NOTE: package None: task do_build: Succeeded
NOTE: Tasks Summary: Attempted 1 tasks of which 0 didn't need to be rerun
and all succeeded.
A few things to note:
1) This is not the *smallest* such BitBake project. For example, the
"DESCRIPTION" and "PV" variables need not be assigned in "a.bb". I set those
variables because I wanted "show-layers" and "show-recipes" to display
reasonable information.
2) Some of the variables set in "bitbake.conf" have "simplified" values. For
example, you would *not* want to use these values if there were multiple
recipes and you had to disambiguate the output from each of them.
3) On the other hand, *all* the variable assignments in "bitbake.conf" are
*essential* to BitBake itself. If you remove any one of those assignments,
BitBake will either declare an error or die (usually because some internal
variable is set to "None" and the BitBake code can't handle it).
------------------------------------------------------------
├── build
│ │
│ ├── classes
│ │ │
│ │ └── base.bbclass
│ │
│ │ +-----------------------------------------------
│ │ | addtask build
│ │ +-----------------------------------------------
│ │
│ └── conf
│ │
│ ├── bblayers.conf
│ │
│ │ +-----------------------------------------------
│ │ | BBLAYERS ?= " \
│ │ | /home/pturley/Workspace/Hello/LayerA \
│ │ | "
│ │ +-----------------------------------------------
│ │
│ └── bitbake.conf
│
│ +-----------------------------------------------
│ | TMPDIR = "${TOPDIR}/tmp"
│ | CACHE = "${TMPDIR}/cache"
│ | STAMP = "${TMPDIR}/stamps"
│ | T = "${TMPDIR}/work"
│ | B = "${TMPDIR}"
│ +-----------------------------------------------
│
├── LayerA
│ │
│ ├── a.bb
│ │
│ │ +-----------------------------------------------
│ │ | DESCRIPTION = "Layer A Recipe"
│ │ | PN = 'a'
│ │ | PV = '1'
│ │ |
│ │ | python do_build() {
│ │ | bb.plain("Hello, World!");
│ │ | }
│ │ +-----------------------------------------------
│ │
│ └── conf
│ │
│ └── layer.conf
│
│ +-----------------------------------------------
│ | BBPATH .= ":${LAYERDIR}"
│ |
│ | BBFILES += "${LAYERDIR}/*.bb"
│ |
│ | BBFILE_COLLECTIONS += "A"
│ | BBFILE_PATTERN_A := "^${LAYERDIR}/"
│ +-----------------------------------------------
│
└── BitBake
The BitBake directory origin is:
http://git.openembedded.org/bitbake/
I have the 1.15.2 tag checked out, which is what
Yocto denzil uses.
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