Add CLI argument to dispatch endpoint

In this way, the user can specify which execution endpoint
to use depending on the execution properties.

4 files changed, 33 insertions, 2 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index fe57bcc7..bdb281ac 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,7 +7,9 @@ A feature release on top of `1.1.0`, backwards compatible.
 - Actions can now define additional execution properties and in
   that way chose a specific remote execution image, as well as a
   factor to scale the time out. This also applies to the built-in
-  `generic` rule.
+  `generic` rule. Additionally, the remote-execution endpoint can
+  be dispatched based on the remote-execution properties using
+  the `--endpoint-configuration` argument.
 - Relative non-upwards symbolic links are now treated as first-class
   objects. This introduces a new artifact type and allows the free use
   of such symbolic links throughout the build process.
diff --git a/share/man/just.1.md b/share/man/just.1.md
index 19a748cc..aaa4e4f5 100644
--- a/share/man/just.1.md
+++ b/share/man/just.1.md
@@ -495,6 +495,20 @@ Supported by: analyse|build|install|rebuild|traverse.
 Address of the remote execution service.  
 Supported by: analyse|build|install-cas|install|rebuild|traverse.
 
+**`--endpoint-configuration`** FILE  
+File containing a description on how to dispatch to different
+remote-execution endpoints based on the the execution properties.
+The format is a JSON list of pairs (lists of length two) of an object
+of strings and a string. The first entry describes a condition (the
+remote-execution properties have to agree on the domain of this
+object), the is remote-exeuction address in the NAME:PORT format as
+for the **`-r`** option. The first matching entry (if any) is taken;
+in none matches the default execution endpoint is taken (either
+as specified by **`-r`**, or local execution if no endpoint is
+specified).  
+Supported by: analyse|build|install-cas|install|rebuild|traverse.
+
+
 Authentication options
 ----------------------
 
diff --git a/src/buildtool/common/cli.hpp b/src/buildtool/common/cli.hpp
index d3d15409..74ff0cce 100644
--- a/src/buildtool/common/cli.hpp
+++ b/src/buildtool/common/cli.hpp
@@ -90,6 +90,7 @@ struct EndpointArguments {
     std::optional<std::filesystem::path> local_root{};
     std::optional<std::string> remote_execution_address;
     std::vector<std::string> platform_properties;
+    std::optional<std::filesystem::path> remote_execution_dispatch_file{};
 };
 
 /// \brief Arguments required for building.
@@ -378,8 +379,13 @@ static inline auto SetupEndpointArguments(
     gsl::not_null<EndpointArguments*> const& clargs) {
     app->add_option("-r,--remote-execution-address",
                     clargs->remote_execution_address,
-                    "Address of the remote execution service.")
+                    "Address of the remote-execution service.")
         ->type_name("NAME:PORT");
+    app->add_option("--endpoint-configuration",
+                    clargs->remote_execution_dispatch_file,
+                    "File with dispatch instructions to use different "
+                    "remote-execution services, depending on the properties")
+        ->type_name("PATH");
     app->add_option(
            "--remote-execution-property",
            clargs->platform_properties,
diff --git a/src/buildtool/main/main.cpp b/src/buildtool/main/main.cpp
index ceecc77c..846fe257 100644
--- a/src/buildtool/main/main.cpp
+++ b/src/buildtool/main/main.cpp
@@ -330,6 +330,15 @@ void SetupExecutionConfig(EndpointArguments const& eargs,
             std::exit(kExitFailure);
         }
     }
+    if (eargs.remote_execution_dispatch_file) {
+        if (not RemoteConfig::SetRemoteExecutionDispatch(
+                *eargs.remote_execution_dispatch_file)) {
+            Logger::Log(LogLevel::Error,
+                        "setting remote execution dispatch based on file '{}'",
+                        eargs.remote_execution_dispatch_file->string());
+            std::exit(kExitFailure);
+        }
+    }
     if (rargs.cache_endpoint) {
         if (not(RemoteConfig::SetCacheAddress(*rargs.cache_endpoint) ==
                 (*rargs.cache_endpoint != "local"))) {