diff --git a/nix/ofborg-carnix.nix b/nix/ofborg-carnix.nix
index ae804a3..b22d24e 100644
--- a/nix/ofborg-carnix.nix
+++ b/nix/ofborg-carnix.nix
@@ -182,6 +182,13 @@ rec {
     sha256 = "1bxsh6fags7nr36vlz07ik2a1rzyipc8x1y30kjk832hf2pzadmw";
     inherit dependencies buildDependencies features;
   };
+  either_1_4_0_ = { dependencies?[], buildDependencies?[], features?[] }: buildRustCrate {
+    crateName = "either";
+    version = "1.4.0";
+    authors = [ "bluss" ];
+    sha256 = "04kpfd84lvyrkb2z4sljlz2d3d5qczd0sb1yy37fgijq2yx3vb37";
+    inherit dependencies buildDependencies features;
+  };
   enum_primitive_0_1_1_ = { dependencies?[], buildDependencies?[], features?[] }: buildRustCrate {
     crateName = "enum_primitive";
     version = "0.1.1";
@@ -974,6 +981,17 @@ rec {
   dtoa_0_4_2_features = f: updateFeatures f (rec {
     dtoa_0_4_2.default = (f.dtoa_0_4_2.default or true);
   }) [];
+  either_1_4_0 = { features?(either_1_4_0_features {}) }: either_1_4_0_ {
+    dependencies = mapFeatures features ([]);
+    features = mkFeatures (features.either_1_4_0 or {});
+  };
+  either_1_4_0_features = f: updateFeatures f (rec {
+    either_1_4_0.default = (f.either_1_4_0.default or true);
+    either_1_4_0.use_std =
+      (f.either_1_4_0.use_std or false) ||
+      (f.either_1_4_0.default or false) ||
+      (either_1_4_0.default or false);
+  }) [];
   enum_primitive_0_1_1 = { features?(enum_primitive_0_1_1_features {}) }: enum_primitive_0_1_1_ {
     dependencies = mapFeatures features ([ num_traits_0_1_41 ]);
   };
@@ -1325,10 +1343,11 @@ rec {
     num_cpus_1_8_0.default = (f.num_cpus_1_8_0.default or true);
   }) [ libc_0_2_36_features ];
   ofborg_0_1_1 = { features?(ofborg_0_1_1_features {}) }: ofborg_0_1_1_ {
-    dependencies = mapFeatures features ([ amqp_0_1_0 env_logger_0_4_3 fs2_0_4_3 hubcaps_0_3_16 hyper_0_10_13 hyper_native_tls_0_2_4 log_0_3_8 lru_cache_0_1_1 md5_0_3_6 serde_1_0_27 serde_derive_1_0_27 serde_json_1_0_9 tempfile_2_2_0 uuid_0_4_0 ]);
+    dependencies = mapFeatures features ([ amqp_0_1_0 either_1_4_0 env_logger_0_4_3 fs2_0_4_3 hubcaps_0_3_16 hyper_0_10_13 hyper_native_tls_0_2_4 log_0_3_8 lru_cache_0_1_1 md5_0_3_6 serde_1_0_27 serde_derive_1_0_27 serde_json_1_0_9 tempfile_2_2_0 uuid_0_4_0 ]);
   };
   ofborg_0_1_1_features = f: updateFeatures f (rec {
     amqp_0_1_0.default = true;
+    either_1_4_0.default = true;
     env_logger_0_4_3.default = true;
     fs2_0_4_3.default = true;
     hubcaps_0_3_16.default = true;
@@ -1344,7 +1363,7 @@ rec {
     tempfile_2_2_0.default = true;
     uuid_0_4_0.default = true;
     uuid_0_4_0.v4 = true;
-  }) [ amqp_0_1_0_features env_logger_0_4_3_features fs2_0_4_3_features hubcaps_0_3_16_features hyper_0_10_13_features hyper_native_tls_0_2_4_features log_0_3_8_features lru_cache_0_1_1_features md5_0_3_6_features serde_1_0_27_features serde_derive_1_0_27_features serde_json_1_0_9_features tempfile_2_2_0_features uuid_0_4_0_features ];
+  }) [ amqp_0_1_0_features either_1_4_0_features env_logger_0_4_3_features fs2_0_4_3_features hubcaps_0_3_16_features hyper_0_10_13_features hyper_native_tls_0_2_4_features log_0_3_8_features lru_cache_0_1_1_features md5_0_3_6_features serde_1_0_27_features serde_derive_1_0_27_features serde_json_1_0_9_features tempfile_2_2_0_features uuid_0_4_0_features ];
   openssl_0_9_23 = { features?(openssl_0_9_23_features {}) }: openssl_0_9_23_ {
     dependencies = mapFeatures features ([ bitflags_0_9_1 foreign_types_0_3_2 lazy_static_1_0_0 libc_0_2_36 openssl_sys_0_9_24 ]);
     features = mkFeatures (features.openssl_0_9_23 or {});
diff --git a/ofborg/Cargo.lock b/ofborg/Cargo.lock
index e766847..beaf34a 100644
--- a/ofborg/Cargo.lock
+++ b/ofborg/Cargo.lock
@@ -132,6 +132,11 @@ name = "dtoa"
 version = "0.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "either"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "enum_primitive"
 version = "0.1.1"
@@ -377,6 +382,7 @@ name = "ofborg"
 version = "0.1.1"
 dependencies = [
  "amqp 0.1.0 (git+https://github.com/grahamc/rust-amqp.git)",
+ "either 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "fs2 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "hubcaps 0.3.16 (git+https://github.com/grahamc/hubcaps.git)",
@@ -761,6 +767,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum core-foundation 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "25bfd746d203017f7d5cbd31ee5d8e17f94b6521c7af77ece6c9e4b2d4b16c67"
 "checksum core-foundation-sys 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "065a5d7ffdcbc8fa145d6f0746f3555025b9097a9e9cda59f7467abae670c78d"
 "checksum dtoa 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)" = "09c3753c3db574d215cba4ea76018483895d7bff25a31b49ba45db21c48e50ab"
+"checksum either 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "740178ddf48b1a9e878e6d6509a1442a2d42fd2928aae8e7a6f8a36fb01981b3"
 "checksum enum_primitive 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "be4551092f4d519593039259a9ed8daedf0da12e5109c5280338073eaeb81180"
 "checksum env_logger 0.3.5 (registry+https://github.com/rust-lang/crates.io-index)" = "15abd780e45b3ea4f76b4e9a26ff4843258dd8a3eed2775a0e7368c2e7936c2f"
 "checksum env_logger 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "3ddf21e73e016298f5cb37d6ef8e8da8e39f91f9ec8b0df44b7deb16a9f8cd5b"
diff --git a/ofborg/Cargo.toml b/ofborg/Cargo.toml
index 9607cc4..d7e3f78 100644
--- a/ofborg/Cargo.toml
+++ b/ofborg/Cargo.toml
@@ -7,6 +7,7 @@ build = "build.rs"
 
 
 [dependencies]
+either = "1.4.0"
 log = "= 0.3.8"
 env_logger = "= 0.4.3"
 # amqp = { path = "./rust-amqp/" } # for testing patches
diff --git a/ofborg/src/lib.rs b/ofborg/src/lib.rs
index bda70db..509efa1 100644
--- a/ofborg/src/lib.rs
+++ b/ofborg/src/lib.rs
@@ -9,7 +9,7 @@ extern crate log;
 extern crate hubcaps;
 extern crate hyper;
 extern crate hyper_native_tls;
-
+extern crate either;
 extern crate lru_cache;
 extern crate tempfile;
 extern crate amqp;
diff --git a/ofborg/src/message/buildlogmsg.rs b/ofborg/src/message/buildlogmsg.rs
index e88379b..00f44dc 100644
--- a/ofborg/src/message/buildlogmsg.rs
+++ b/ofborg/src/message/buildlogmsg.rs
@@ -1,5 +1,5 @@
 
-#[derive(Serialize, Deserialize, Debug)]
+#[derive(Serialize, Deserialize, Debug, Clone)]
 pub struct BuildLogMsg {
     pub system: String,
     pub identity: String,
@@ -8,7 +8,7 @@ pub struct BuildLogMsg {
     pub output: String,
 }
 
-#[derive(Serialize, Deserialize, Debug)]
+#[derive(Serialize, Deserialize, Debug, Clone)]
 pub struct BuildLogStart {
     pub system: String,
     pub identity: String,
diff --git a/ofborg/src/tasks/log_message_collector.rs b/ofborg/src/tasks/log_message_collector.rs
index 64d1e81..623c36a 100644
--- a/ofborg/src/tasks/log_message_collector.rs
+++ b/ofborg/src/tasks/log_message_collector.rs
@@ -1,14 +1,16 @@
 extern crate amqp;
 extern crate env_logger;
 
+use either::{Either, Left, Right};
 use lru_cache::LruCache;
 use serde_json;
 use std::fs;
 use std::fs::{OpenOptions, File};
 use std::path::{Component, PathBuf};
+use std::io::Write;
 
 use ofborg::writetoline::LineWriter;
-use ofborg::message::buildlogmsg::BuildLogMsg;
+use ofborg::message::buildlogmsg::{BuildLogStart, BuildLogMsg};
 use ofborg::worker;
 use amqp::protocol::basic::{Deliver, BasicProperties};
 
@@ -26,7 +28,7 @@ pub struct LogMessageCollector {
 #[derive(Debug)]
 pub struct LogMessage {
     from: LogFrom,
-    message: BuildLogMsg,
+    message: Either<BuildLogStart, BuildLogMsg>,
 }
 
 fn validate_path_segment(segment: &PathBuf) -> Result<(), String> {
@@ -58,14 +60,32 @@ impl LogMessageCollector {
         };
     }
 
+    pub fn write_metadata(&mut self, from: &LogFrom, data: &BuildLogStart) -> Result<(), String>{
+        let metapath = self.path_for_metadata(&from)?;
+        let mut fp = self.open_file(metapath)?;
+
+        match serde_json::to_string(data) {
+            Ok(data) => {
+                if let Err(e) = fp.write(&data.as_bytes()) {
+                    Err(format!("Failed to write metadata: {:?}", e))
+                } else {
+                    Ok(())
+                }
+            },
+            Err(e) => {
+                Err(format!("Failed to stringify metadata: {:?}", e))
+            }
+        }
+    }
+
     pub fn handle_for(&mut self, from: &LogFrom) -> Result<&mut LineWriter, String> {
         if self.handles.contains_key(&from) {
             return Ok(self.handles.get_mut(&from).expect(
                 "handles just contained the key",
             ));
         } else {
-            let logpath = self.path_for(&from)?;
-            let fp = self.open_log(logpath)?;
+            let logpath = self.path_for_log(&from)?;
+            let fp = self.open_file(logpath)?;
             let writer = LineWriter::new(fp);
             self.handles.insert(from.clone(), writer);
             if let Some(handle) = self.handles.get_mut(&from) {
@@ -78,7 +98,13 @@ impl LogMessageCollector {
         }
     }
 
-    fn path_for(&self, from: &LogFrom) -> Result<PathBuf, String> {
+    fn path_for_metadata(&self, from: &LogFrom) -> Result<PathBuf, String> {
+        let mut path = self.path_for_log(from)?;
+        path.set_extension("metadata.json");
+        return Ok(path);
+    }
+
+    fn path_for_log(&self, from: &LogFrom) -> Result<PathBuf, String> {
         let mut location = self.log_root.clone();
 
         let routing_key = PathBuf::from(from.routing_key.clone());
@@ -100,7 +126,7 @@ impl LogMessageCollector {
         }
     }
 
-    fn open_log(&self, path: PathBuf) -> Result<File, String> {
+    fn open_file(&self, path: PathBuf) -> Result<File, String> {
         let dir = path.parent().unwrap();
         fs::create_dir_all(dir).unwrap();
 
@@ -114,7 +140,7 @@ impl LogMessageCollector {
         match attempt {
             Ok(handle) => Ok(handle),
             Err(e) => Err(format!(
-                "Failed to open the log file for {:?}, err: {:?}",
+                "Failed to open the file for {:?}, err: {:?}",
                 &path,
                 e
             )),
@@ -144,14 +170,22 @@ impl worker::SimpleWorker for LogMessageCollector {
                 routing_key: deliver.routing_key.clone(),
                 attempt_id: message.attempt_id.clone(),
             },
-            message: message,
+            message: Right(message),
         })
     }
 
     fn consumer(&mut self, job: &LogMessage) -> worker::Actions {
-        let handle = self.handle_for(&job.from).unwrap();
+        match job.message {
+            Left(ref start) => {
+                self.write_metadata(&job.from, &start).expect("failed to write metadata");
+            },
+            Right(ref message) => {
+                let handle = self.handle_for(&job.from).unwrap();
 
-        handle.write_to_line((job.message.line_number - 1) as usize, &job.message.output);
+                handle.write_to_line((message.line_number - 1) as usize,
+                                     &message.output);
+            }
+        }
 
         return vec![worker::Action::Ack];
     }
@@ -194,12 +228,29 @@ mod tests {
     }
 
     #[test]
-    fn test_path_for() {
-        let p = TestScratch::new_dir("log-message-collector-path_for");
+    fn test_path_for_metadata() {
+        let p = TestScratch::new_dir("log-message-collector-path_for_metadata");
         let worker = make_worker(p.path());
 
         let path = worker
-            .path_for(&LogFrom {
+            .path_for_metadata(&LogFrom {
+                attempt_id: String::from("my-attempt-id"),
+                routing_key: String::from("my-routing-key"),
+            })
+            .expect("the path should be valid");
+
+
+        assert!(path.starts_with(p.path()));
+        assert!(path.as_os_str().to_string_lossy().ends_with("my-routing-key/my-attempt-id.metadata.json"));
+    }
+
+    #[test]
+    fn test_path_for_log() {
+        let p = TestScratch::new_dir("log-message-collector-path_for_log");
+        let worker = make_worker(p.path());
+
+        let path = worker
+            .path_for_log(&LogFrom {
                 attempt_id: String::from("my-attempt-id"),
                 routing_key: String::from("my-routing-key"),
             })
@@ -211,11 +262,11 @@ mod tests {
     }
 
     #[test]
-    fn test_path_for_malicious() {
+    fn test_path_for_log_malicious() {
         let p = TestScratch::new_dir("log-message-collector-for_malicious");
         let worker = make_worker(p.path());
 
-        let path = worker.path_for(&LogFrom {
+        let path = worker.path_for_log(&LogFrom {
             attempt_id: String::from("./../../"),
             routing_key: String::from("./../../foobar"),
         });
@@ -242,52 +293,75 @@ mod tests {
 
 
     #[test]
-    fn test_open_log() {
-        let p = TestScratch::new_dir("log-message-collector-open_log");
+    fn test_open_file() {
+        let p = TestScratch::new_dir("log-message-collector-open_file");
         let worker = make_worker(p.path());
 
         assert!(
             worker
-                .open_log(worker.path_for(&make_from("a")).unwrap())
+                .open_file(worker.path_for_log(&make_from("a")).unwrap())
                 .is_ok()
         );
         assert!(
             worker
-                .open_log(worker.path_for(&make_from("b.foo/123")).unwrap())
+                .open_file(worker.path_for_log(&make_from("b.foo/123")).unwrap())
                 .is_ok()
         );
     }
 
     #[test]
     pub fn test_logs_collect() {
+        let mut logmsg = BuildLogMsg {
+            attempt_id: String::from("my-attempt-id"),
+            identity: String::from("my-identity"),
+            system: String::from("foobar-x8664"),
+            line_number: 1,
+            output: String::from("line-1"),
+        };
         let mut job = LogMessage {
             from: make_from("foo"),
-            message: BuildLogMsg {
-                attempt_id: String::from("my-attempt-id"),
-                identity: String::from("my-identity"),
-                system: String::from("foobar-x8664"),
-                line_number: 1,
-                output: String::from("line-1"),
-            },
+            message: Right(logmsg.clone()),
         };
 
-        let p = TestScratch::new_dir("log-message-collector-path_for");
+        let p = TestScratch::new_dir("log-message-collector-path_for_log");
 
         {
             let mut worker = make_worker(p.path());
+            assert_eq!(vec![worker::Action::Ack],
+                       worker.consumer(&
+                                       LogMessage {
+                                           from: make_from("foo"),
+                                           message: Left(BuildLogStart {
+                                               attempt_id: String::from("my-attempt-id"),
+                                               identity: String::from("my-identity"),
+                                               system: String::from("foobar-x8664"),
+                                           })
+                                       }
+                       )
+            );
+
             assert_eq!(vec![worker::Action::Ack], worker.consumer(&job));
 
-            job.message.line_number = 5;
-            job.message.output = String::from("line-5");
+            logmsg.line_number = 5;
+            logmsg.output = String::from("line-5");
+            job.message = Right(logmsg.clone());
             assert_eq!(vec![worker::Action::Ack], worker.consumer(&job));
 
             job.from.attempt_id = String::from("my-other-attempt");
-            job.message.attempt_id = String::from("my-other-attempt");
-            job.message.line_number = 3;
-            job.message.output = String::from("line-3");
+            logmsg.attempt_id = String::from("my-other-attempt");
+            logmsg.line_number = 3;
+            logmsg.output = String::from("line-3");
+            job.message = Right(logmsg.clone());
             assert_eq!(vec![worker::Action::Ack], worker.consumer(&job));
         }
 
+        let mut pr = p.path();
+        let mut s = String::new();
+        pr.push("routing-key-foo/attempt-id-foo.metadata.json");
+        File::open(pr).unwrap().read_to_string(&mut s).unwrap();
+        assert_eq!(&s, "{\"system\":\"foobar-x8664\",\"identity\":\"my-identity\",\"attempt_id\":\"my-attempt-id\"}");
+
+
         let mut pr = p.path();
         let mut s = String::new();
         pr.push("routing-key-foo/attempt-id-foo");