topotato: has_logmsg & has_defun for templates

Already have these implemented for requirements checks, also allow using
them in templates to determine what to put in FRR configs.

Signed-off-by: David Lamparter <[email protected]>

topotato/frr/params.py

@@ -103,7 +103,7 @@ def __init__(self, instance: TopotatoNetwork, name: str):
                     router=router,
                     routers=rtrmap,
                     topo=topo,
-                    frr=TemplateUtils(router, daemon),
+                    frr=TemplateUtils(router, daemon, self),
                 )
 
         # TODO: rework mgmtd integration, particularly for supporting older
@@ -176,17 +176,41 @@ def require_defun(self, cmd: str, contains: Optional[str] = None) -> None:
                         f"DEFUN {cmd!r} does not contain {contains!r}"
                     )
 
-    def require_logmsg(self, msgid: str) -> None:
+    def has_defun(self, cmd: str, contains: Optional[str] = None) -> bool:
+        """
+        Wrap :py:meth:`require_defun`, but return a bool rather than throwing
+        an exception.
+
+        This wrapper is "the other way around" because the exception thrown
+        above contains additional information beyond what can be conveyed in a
+        ``bool``.
+        """
+        try:
+            self.require_defun(cmd, contains)
+            return True
+        except FRRRequirementNotMet:
+            return False
+
+    def has_logmsg(self, msgid: str) -> bool:
         """
         Check that a log message exists in this FRR version by looking up its
         unique ID in ``frr.xref``.
 
+        :param msgid: ID (``XXXXX-XXXXX``) of the log message to look for.
+        """
+        return msgid in (self.frr.xrefs or {}).get("refs", {})
+
+    def require_logmsg(self, msgid: str) -> None:
+        """
+        Wrap :py:meth:`has_logmsg` and raise exception if given log message
+        does not exist in this FRR version.
+
         :param msgid: ID (``XXXXX-XXXXX``) of the log message to look for.
         :raises FRRRequirementNotMet: if the log message is not found.  This
             causes the test to be skipped, but can be caught (e.g. if there
             are multiple alternatives to check.)
         """
-        if msgid not in (self.frr.xrefs or {}).get("refs", {}):
+        if not self.has_logmsg(msgid):
             raise FRRRequirementNotMet(f"missing log message {msgid!r}")
 
     def requirements(self) -> None:

topotato/frr/templating.py

@@ -11,6 +11,7 @@
     Callable,
     List,
     Literal,
+    Optional,
     Set,
     Tuple,
     Union,
@@ -21,6 +22,7 @@
 
 if typing.TYPE_CHECKING:
     from .. import toponom
+    from .params import FRRParams
 
 jenv = jinlinja.InlineEnv()
 
@@ -52,6 +54,7 @@
 class TemplateUtils:
     router: "toponom.Router"
     daemon: str
+    params: "FRRParams"
 
     def static_route_for(
         self,
@@ -95,3 +98,23 @@ def static_route_for(
                 queue.append((nbr, nbr_path))
 
         raise RuntimeError(f"no route for {dst!r} on {self.router!r}")
+
+    def has_defun(self, cmd: str, contains: Optional[str] = None) -> bool:
+        """
+        Expose :py:meth:`FRRParams.has_defun` for template use.
+
+        :param cmd: Name of the command as defined in the C source, i.e.
+            second argument to `DEFUN` macro.  Generally ends in ``_cmd``.
+        :param contains: String that must appear in the command's syntax
+            definition (use if some new option is added to an existing
+            command.)
+        """
+        return self.params.has_defun(cmd, contains)
+
+    def has_logmsg(self, msgid: str) -> bool:
+        """
+        Expose :py:meth:`FRRParams.has_logmsg` for template use.
+
+        :param msgid: ID (``XXXXX-XXXXX``) of the log message to look for.
+        """
+        return self.params.has_logmsg(msgid)