config: Substitutions prefer %{...} to %(...)s, document, etc.

[hippotat.git] / src / config.rs

diff --git a/src/config.rs b/src/config.rs
index 76cafdb0620950e4f43f9740b419ebc3872955d8..4b94b3ed73357db4659e2c3fde777e4e67b13e66 100644 (file)
--- a/src/config.rs
+++ b/src/config.rs
@@ -54,11 +54,11 @@ max_batch_up = 4000
 http_retry = 5
 port = 80
 vroutes = ''
-ifname_client = hippo%%d
-ifname_server = shippo%%d
+ifname_client = hippo%d
+ifname_server = shippo%d
 max_clock_skew = 300
 
-ipif = userv root ipif %(local)s,%(peer)s,%(mtu)s,slip,%(ifname)s '%(rnets)s'
+ipif = userv root ipif %{local},%{peer},%{mtu},slip,%{ifname} '%{rnets}'
 
 mtu = 1500
 
@@ -684,6 +684,63 @@ impl InstanceConfig {
         }
       },
     }
+
+    #[throws(AE)]
+    fn subst(var: &mut String,
+             kv: &mut dyn Iterator<Item=(&'static str, &dyn Display)>
+    ) {
+      let substs = kv
+        .map(|(k,v)| (k.to_string(), v.to_string()))
+        .collect::<HashMap<String, String>>();
+      let bad = parking_lot::Mutex::new(vec![]);
+      *var = regex_replace_all!(
+        r#"%(?:%|\((\w+)\)s|\{(\w+)\}|.)"#,
+        &var,
+        |whole, k1, k2| (|| Ok::<_,String>({
+          if whole == "%%" { "%" }
+          else if let Some(&k) = [k1,k2].iter().find(|&&s| s != "") {
+            substs.get(k).ok_or_else(
+              || format!("unknown key %({})s", k)
+            )?
+          } else {
+            throw!(format!("bad percent escape {:?}", &whole));
+          }
+        }))().unwrap_or_else(|e| { bad.lock().push(e); "" })
+      ).into_owned();
+      let bad = bad.into_inner();
+      if ! bad.is_empty() {
+        throw!(anyhow!("substitution failed: {}", bad.iter().format("; ")));
+      }
+    }
+
+    {
+      use LinkEnd::*;
+      type DD<'d> = &'d dyn Display;
+      fn dv<T:Display>(v: &[T]) -> String {
+        format!("{}", v.iter().format(" "))
+      }
+      let mut ipif = mem::take(&mut self.ipif); // lets us borrow all of self
+      let s = &self; // just for abbreviation, below
+      let vnetwork = dv(&s.vnetwork);
+      let vroutes  = dv(&s.vroutes);
+
+      let keys = &["local",       "peer",    "rnets",   "ifname"];
+      let values = match end {
+ Server => [&s.vaddr as DD      , &s.vrelay, &vnetwork, &s.ifname_server],
+ Client => [&s.link.client as DD, &s.vaddr,  &vroutes,  &s.ifname_client],
+      };
+      let always = [
+        ( "mtu",     &s.mtu as DD ),
+      ];
+
+      subst(
+        &mut ipif,
+        &mut keys.iter().cloned()
+          .zip_eq(values)
+          .chain(always.iter().cloned()),
+      ).context("ipif")?;
+      self.ipif = ipif;
+    }
   }
 }