expose graphviz-file arg from nix

README.md

@@ -270,6 +270,10 @@ onix.env {
   # Example: `opam-lock = ./my-project.opam.locked;`
   opam-lock = null;
 
+  # The path to the graphviz "dot" file with a dependency graph.
+  # Example: `graphviz-file = ./onix-lock.dot;`
+  graphviz-file = null;
+
   # Package variables.
   vars = {
     "with-test" = false;

nix/api.nix

@@ -34,6 +34,10 @@ let
     "onix: env-file argument must be a path or a null value, found: ${
       builtins.toJSON envFile
     }";
+  errInvalidGraphvizFile = path:
+    "onix: graphviz-file argument must be a path or a null value, found: ${
+      builtins.toJSON path
+    }";
   errInvalidVars = "onix: vars argument must be an attrset";
   errInvalidOverlay = "onix: overlay must be a function or a null value";
   errRequiredRootPath =
@@ -144,6 +148,12 @@ let
     else
       throw errInvalidOverlay;
 
+  validateGraphvizFile = path:
+    if isString path || isPath path || isNull path then
+      path
+    else
+      throw (errInvalidGraphvizFile path);
+
   # Process arguments.
 
   processRootPath = { gitignore, rootPath }:
@@ -256,6 +266,11 @@ in {
       # The path to the opam lock file.
     , opam-lock ? null
 
+      # The path to the graphviz "dot" file that will be generated. This file
+      # will contain the dependency tree graph. If "null" (the default), the file will
+      # not be generated.
+    , graphviz-file ? null
+
       # Package variables.
     , vars ? { }
 
@@ -276,6 +291,7 @@ in {
         vars = validateVars vars;
         env-file = validateEnvFile env-file;
         opam-lock = validateLock opam-lock;
+        graphviz-file = validateGraphvizFile graphviz-file;
         overlay = validateOverlay overlay;
       };
 
@@ -292,6 +308,7 @@ in {
           processPathRelativeToRoot validatedArgs.rootPath validatedArgs.lock;
         opam-lock = processPathRelativeToRoot validatedArgs.rootPath
           validatedArgs.opam-lock;
+        graphviz-file = processPathRelativeToRoot validatedArgs.rootPath validatedArgs.graphviz-file;
         vars = processVars validatedArgs.vars;
         env-file = processPathRelativeToRoot validatedArgs.rootPath
           validatedArgs.env-file;
@@ -325,6 +342,7 @@ in {
         constraints = config.constraints;
         vars = config.vars;
         opamFiles = config.opamFiles;
+        graphvizPath = config.graphviz-file;
       };
 
       pkgs = allPkgs;

nix/core.nix

@@ -283,7 +283,7 @@ let
 
 in {
   lock =
-    { lockPath, opamLockPath, opamFiles, repositoryUrls, constraints, vars }:
+    { lockPath, opamLockPath, opamFiles, repositoryUrls, constraints, vars, graphvizPath }:
     let
       repositoryUrlsArg = lib.strings.concatStringsSep "," (map (repositoryUrl:
         if repositoryUrl ? "rev" then
@@ -308,11 +308,15 @@ in {
         " --lock-file=${lockPath}";
       opamLockPathOpt =
         if isNull opamLockPath then "" else " --opam-lock-file=${opamLockPath}";
+      graphvizPathOpt = if isNull graphvizPath then
+        ""
+      else
+        " --graphviz-file=${graphvizPath}";
 
     in pkgs.mkShell {
       buildInputs = [ onix ];
       shellHook = ''
-        onix lock${lockPathOpt}${opamLockPathOpt} \
+        onix lock${lockPathOpt}${opamLockPathOpt}${graphvizPathOpt} \
           --repository-urls='${repositoryUrlsArg}' \
           --resolutions='${mkResolutionsArg constraints}' \
           --with-test=${builtins.toJSON vars.with-test} \

src/onix_lock_graphviz/Onix_lock_graphviz.ml

@@ -56,4 +56,4 @@ let gen ~graphviz_file_path (lock_file : Lock_file.t) =
       let out = Format.formatter_of_out_channel chan in
       Fmt.pf out "%a" pp pkgs);
   Logs.info (fun log ->
-      log "Created an opam lock file at %S." graphviz_file_path)
+      log "Created an graphviz file at %S." graphviz_file_path)