[meta-OE][PATCH v3] image.bbclass: deploy image artifacts in stages

["Bartosz Golaszewski" <brgl@bgdev.pl>]

From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Make each IMAGE_CMD task an sstate task with its own IMGDEPLOYDIR
override. This way each generated set of artifacts is deployed as soon
as it's ready instead of the do_image_complete task handling the entire
deployement. This allows us to better fine-tune dependencies e.g. we
can make do_image_wic depend on fitImage task which can in turn depend
on do_image_ext4.

We need delete the IMGDEPLOYDIR variable from the data object passed
to each image task so that it gets expanded with the correct override.

In order to make sure that tasks added to SSTATETASKS in anonymous python
functions are correctly setup, move the code that assigns pre- and
postfuncs to an event handler invoked on bb.event.RecipeTaskPreProcess
in sstate.bbclass. This event is fired right after the anonymous
functions.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
Changes since v2:
- dropped the qemuboot patch (already upstream)
- switched to % string formatting instead of using .format() for consistency

 meta/classes/image.bbclass  | 17 +++++++++++++++++
 meta/classes/sstate.bbclass |  4 ++++
 2 files changed, 21 insertions(+)

diff --git a/meta/classes/image.bbclass b/meta/classes/image.bbclass
index 694b58fc9f..3cf8ceb2d6 100644
--- a/meta/classes/image.bbclass
+++ b/meta/classes/image.bbclass
@@ -425,10 +425,12 @@ python () {
         # date/time values. It will get expanded at execution time.
         # Similarly TMPDIR since otherwise we see QA stamp comparision problems
         # Expand PV else it can trigger get_srcrev which can fail due to these variables being unset
+        # Delete IMGDEPLOYDIR so that each task gets its own, overriden value
         localdata.setVar('PV', d.getVar('PV'))
         localdata.delVar('DATETIME')
         localdata.delVar('DATE')
         localdata.delVar('TMPDIR')
+        localdata.delVar('IMGDEPLOYDIR')
         vardepsexclude = (d.getVarFlag('IMAGE_CMD_' + realt, 'vardepsexclude', True) or '').split()
         for dep in vardepsexclude:
             localdata.delVar(dep)
@@ -499,6 +501,21 @@ python () {
 
         bb.debug(2, "Adding task %s before %s, after %s" % (task, 'do_image_complete', after))
         bb.build.addtask(task, 'do_image_complete', after, d)
+
+        imgdeploydir = d.getVar('IMGDEPLOYDIR')
+        task_override = task[3:].replace('_', '-') # 'do_image_ext4' becomes 'image-ext4'
+        taskdeploydir = '%s/deploy-%s-%s' % (os.path.dirname(imgdeploydir),
+                                             d.getVar('PN'), task_override)
+
+        # Each image task gets its own IMGDEPLOYDIR directory and is added to
+        # SSTATETASKS. This way every set of artifacts gets deployed right after
+        # the do_image_foo task completes.
+        d.setVar('IMGDEPLOYDIR_task-%s' % task_override, taskdeploydir)
+        d.appendVar('SSTATETASKS', ' %s' % task)
+        d.setVarFlag(task, 'sstate-inputdirs', taskdeploydir)
+        d.setVarFlag(task, 'sstate-outputdirs', d.getVar('DEPLOY_DIR_IMAGE'))
+        d.setVarFlag(task, 'cleandirs', taskdeploydir)
+        d.setVar('SSTATE_SKIP_CREATION_task-%s' % task_override, '1')
 }
 
 #
diff --git a/meta/classes/sstate.bbclass b/meta/classes/sstate.bbclass
index aa9c30b4e1..5bdada673f 100644
--- a/meta/classes/sstate.bbclass
+++ b/meta/classes/sstate.bbclass
@@ -138,13 +138,17 @@ python () {
         d.setVar('SSTATE_EXTRAPATH', "${NATIVELSBSTRING}/")
         d.setVar('BB_HASHFILENAME', "True ${SSTATE_PKGSPEC} ${SSTATE_SWSPEC}")
         d.setVar('SSTATE_EXTRAPATHWILDCARD', "${NATIVELSBSTRING}/")
+}
 
+python sstate_setup_tasks() {
     unique_tasks = sorted(set((d.getVar('SSTATETASKS') or "").split()))
     d.setVar('SSTATETASKS', " ".join(unique_tasks))
     for task in unique_tasks:
         d.prependVarFlag(task, 'prefuncs', "sstate_task_prefunc ")
         d.appendVarFlag(task, 'postfuncs', " sstate_task_postfunc")
 }
+addhandler sstate_setup_tasks
+sstate_setup_tasks[eventmask] = "bb.event.RecipeTaskPreProcess"
 
 def sstate_init(task, d):
     ss = {}
-- 
2.25.0