Add Task.add_requirements() to force requirement package into "installed packages"

trains/backend_interface/task/repo/scriptinfo.py

@@ -1,5 +1,6 @@
 import os
 import sys
+from copy import copy
 from tempfile import mkstemp
 
 import attr
@@ -80,6 +81,15 @@ class ScriptRequirements(object):
             except Exception:
                 pass
 
+        # add forced requirements:
+        # noinspection PyBroadException
+        try:
+            from ..task import Task
+            for package, version in Task._force_requirements.items():
+                modules.add(package, 'trains', 0)
+        except Exception:
+            pass
+
         return modules
 
     @staticmethod
@@ -109,6 +119,14 @@ class ScriptRequirements(object):
         except:
             conda_requirements = ''
 
+        # add forced requirements:
+        # noinspection PyBroadException
+        try:
+            from ..task import Task
+            forced_packages = copy(Task._force_requirements)
+        except Exception:
+            forced_packages = {}
+
         # python version header
         requirements_txt = '# Python ' + sys.version.replace('\n', ' ').replace('\r', ' ') + '\n'
 
@@ -120,11 +138,23 @@ class ScriptRequirements(object):
         # requirement summary
         requirements_txt += '\n'
         for k, v in reqs.sorted_items():
+            version = v.version
+            if k in forced_packages:
+                forced_version = forced_packages.pop(k, None)
+                if forced_version:
+                    version = forced_version
             # requirements_txt += ''.join(['# {0}\n'.format(c) for c in v.comments.sorted_items()])
             if k == '-e':
-                requirements_txt += '{0} {1}\n'.format(k, v.version)
+                requirements_txt += '{0} {1}\n'.format(k, version)
             elif v:
-                requirements_txt += '{0} {1} {2}\n'.format(k, '==', v.version)
+                requirements_txt += '{0} {1} {2}\n'.format(k, '==', version)
+            else:
+                requirements_txt += '{0}\n'.format(k)
+
+        # add forced requirements that we could not find installed on the system
+        for k in sorted(forced_packages.keys()):
+            if forced_packages[k]:
+                requirements_txt += '{0} {1} {2}\n'.format(k, '==', forced_packages[k])
             else:
                 requirements_txt += '{0}\n'.format(k)
 

trains/backend_interface/task/task.py

@@ -48,6 +48,7 @@ class Task(IdObjectBase, AccessMixin, SetupUploadMixin):
 
     _anonymous_dataview_id = '__anonymous__'
     _development_tag = 'development'
+    _force_requirements = {}
 
     _store_diff = config.get('development.store_uncommitted_code_diff', False)