_frontend: Added App.shell() to call instead of directly invoking the Element._shell()

And use this place to format a custom prompt for PS1, here
we have click and we use the ANSI colors in PS1 only if colors are
enabled.

2 files changed, 20 insertions, 2 deletions

diff --git a/buildstream/_frontend/cli.py b/buildstream/_frontend/cli.py
index c5fc87bab..29bae1da4 100644
--- a/buildstream/_frontend/cli.py
+++ b/buildstream/_frontend/cli.py
@@ -510,7 +510,8 @@ def shell(app, element, sysroot, isolate, build, command):
         sys.exit(-1)
 
     try:
-        exitcode = app.pipeline.targets[0]._shell(scope, sysroot, isolate=isolate, command=command)
+        element = app.pipeline.targets[0]
+        exitcode = app.shell(element, scope, sysroot, isolate=isolate, command=command)
         sys.exit(exitcode)
     except BstError as e:
         click.echo("", err=True)
diff --git a/buildstream/_frontend/main.py b/buildstream/_frontend/main.py
index dc251748d..9d30dd7fa 100644
--- a/buildstream/_frontend/main.py
+++ b/buildstream/_frontend/main.py
@@ -342,7 +342,7 @@ class App():
                 if choice == 'shell':
                     click.echo("\nDropping into an interactive shell in the failed build sandbox\n", err=True)
                     try:
-                        element._shell(Scope.BUILD, failure.sandbox, isolate=True)
+                        self.shell(element, Scope.BUILD, failure.sandbox, isolate=True)
                     except BstError as e:
                         click.echo("Error while attempting to create interactive shell: {}".format(e), err=True)
                 elif choice == 'log':
@@ -364,6 +364,23 @@ class App():
                     queue.failed_elements.remove(element)
                     queue.enqueue([element])
 
+    def shell(self, element, scope, directory, isolate=False, command=None):
+        _, key, dim = element._get_full_display_key()
+        element_name = element._get_full_name()
+
+        if self.colors:
+            p = Profile()
+            prompt = self.format_profile.fmt('[') + \
+                self.content_profile.fmt(key, dim=dim) + \
+                self.format_profile.fmt('@') + \
+                p.fmt(element_name, fg='blue', bold=True) + \
+                self.format_profile.fmt(']') + ':' + \
+                p.fmt('$PWD', fg='blue', bold=True) + '$ '
+        else:
+            prompt = '[{}@{}]:${{PWD}}$ '.format(key, element_name)
+
+        return element._shell(scope, directory, isolate=isolate, prompt=prompt, command=command)
+
     def tick(self, elapsed):
         self.maybe_render_status()