[PATCH 2/6] base: Implement bitbake build ID

[Anton Mikanovich <amikan@ilbers.de>]

Add internal ID which is unique for any single bitabake run.
BITBAKE_BUILD_ID is calculated as a hash of two variables defined by
bitbake itself at build start:
BUILDNAME - defined as "${DATE}${TIME}" of cooker execution.
TOPDIR - build dir where Isar is building.
Both of them guarantee uniqueness by time and directory.

Signed-off-by: Anton Mikanovich <amikan@ilbers.de>
---
 meta/classes/base.bbclass | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/meta/classes/base.bbclass b/meta/classes/base.bbclass
index 4ec2c81..f6b6a32 100644
--- a/meta/classes/base.bbclass
+++ b/meta/classes/base.bbclass
@@ -278,3 +278,12 @@ def base_set_filespath(path, d):
             if p != "":
                 filespath.append(os.path.join(p, o))
     return ":".join(filespath)
+
+calculate_build_id[vardepsexclude] = "BUILDNAME"
+def calculate_build_id(d):
+    import hashlib
+    build_name = d.getVar("BUILDNAME", True) or ""
+    build_dir = d.getVar("TOPDIR", True) or ""
+    return hashlib.sha1((build_dir + build_name).encode("utf-8")).hexdigest()
+
+BITBAKE_BUILD_ID = "${@ calculate_build_id(d)}"
-- 
2.17.1