resilient: promises to check backup integrity shouldn't fail if proofs do no exist

stack/resilient/buildout.cfg

@@ -50,7 +50,7 @@ mode = 0644
 recipe = slapos.recipe.template
 url = ${:_profile_base_location_}/pbsready-import.cfg.in
 output = ${buildout:directory}/pbsready-import.cfg
-md5sum = cdebc491a50a61fecc3391a5eb311bdb
+md5sum = 89619b0d8626c76402a11bb08e7ba8a1
 mode = 0644
 
 [pbsready-export]
@@ -66,7 +66,7 @@ mode = 0644
 recipe = slapos.recipe.template
 url = ${:_profile_base_location_}/instance-pull-backup.cfg.in
 output = ${buildout:directory}/instance-pull-backup.cfg
-md5sum = 232fcad0892e56d62f45e79ec01c7c3e
+md5sum = fba98fd740d564525fc3f236662f5d64
 mode = 0644
 
 [template-replicated]

stack/resilient/instance-pull-backup.cfg.in

@@ -269,8 +269,16 @@ monitor-username = $${htpasswd:username}
 recipe = slapos.recipe.template:jinja2
 template = inline:
   #!${dash:location}/bin/dash
+  # Raise an error if signatures are different
+  # Error cannot be deduced if files do not exist
   cd $${directory:pbs-backup}
- diff proof.signature $(find . -name backup.signature -maxdepth 2)
+  if [ ! -f "proof.signature" ]; then exit 0; fi
+  backup_signature=$(find . -maxdepth 2 -name backup.signature)
+  if [ -z "$backup_signature" ]; then
+    exit 0;
+  else
+    diff "proof.signature" "$backup_signature";
+  fi
 rendered = $${basedirectory:promises}/backup-transfer-integrity-promise
 mode = 700
 

stack/resilient/pbsready-import.cfg.in

@@ -82,7 +82,17 @@ callback = $${post-notification-run:output}
 recipe = slapos.recipe.template:jinja2
 template = inline:
   #!/${bash:location}/bin/bash
-  if [ "$(wc -l $${post-notification-run:diff-file} | cut -d \  -f1)" -eq 0 ]; then exit 0; else exit 1; fi
+  backup_diff_file=$${post-notification-run:diff-file}
+  if [ -f "$backup_diff_file" ]; then
+    if [ $(wc -l "$backup_diff_file" | cut -d \  -f1) -eq 0 ]; then
+      exit 0;
+    else
+      exit 1;
+    fi
+  else
+    # If file doesn't exist, promise should raise false positive
+    exit 0;
+  fi
 rendered = $${basedirectory:promises}/backup-transfer-integrity-promise
 mode = 700