bitbake: fetch/az: Add sanity check and clarify documentation

AZ_SAS token should be prefixed with a question mark. Add a sanity check for
this and fix the documentation.

[YOCTO #15882]

(Bitbake rev: 22011765202514600314732b97f1bb938e21f585)

Signed-off-by: Robbin Van Damme <robbinvandamme@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

2 files changed, 6 insertions, 2 deletions

diff --git a/bitbake/doc/bitbake-user-manual/bitbake-user-manual-fetching.rst b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-fetching.rst
index fb4f0a23d7..eac3cbdfb5 100644
--- a/bitbake/doc/bitbake-user-manual/bitbake-user-manual-fetching.rst
+++ b/bitbake/doc/bitbake-user-manual/bitbake-user-manual-fetching.rst
@@ -686,9 +686,9 @@ Such functionality is set by the variable:
    delegate access to resources, if this variable is set, the Az Fetcher will
    use it when fetching artifacts from the cloud.
 
-You can specify the AZ_SAS variable as shown below::
+You can specify the AZ_SAS variable prefixed with a ? as shown below::
 
-   AZ_SAS = "se=2021-01-01&sp=r&sv=2018-11-09&sr=c&skoid=<skoid>&sig=<signature>"
+   AZ_SAS = "?se=2021-01-01&sp=r&sv=2018-11-09&sr=c&skoid=<skoid>&sig=<signature>"
 
 Here is an example URL::
 
diff --git a/bitbake/lib/bb/fetch2/az.py b/bitbake/lib/bb/fetch2/az.py
index 346124a8bf..1d3664f213 100644
--- a/bitbake/lib/bb/fetch2/az.py
+++ b/bitbake/lib/bb/fetch2/az.py
@@ -36,6 +36,8 @@ class Az(Wget):
 
         az_sas = d.getVar('AZ_SAS')
         if az_sas and az_sas not in ud.url:
+            if not az_sas.startswith('?'):
+                raise FetchError("When using AZ_SAS, it must start with a '?' character to mark the start of the query-parameters.")
             ud.url += az_sas
 
         return Wget.checkstatus(self, fetch, ud, d, try_again)
@@ -62,6 +64,8 @@ class Az(Wget):
         az_sas = d.getVar('AZ_SAS')
 
         if az_sas:
+            if not az_sas.startswith('?'):
+                raise FetchError("When using AZ_SAS, it must start with a '?' character to mark the start of the query-parameters.")
             azuri = '%s%s%s%s' % ('https://', ud.host, ud.path, az_sas)
         else:
             azuri = '%s%s%s' % ('https://', ud.host, ud.path)