Merge pull request #6557 from grondo/flux-root-opt

add `flux --root` option

doc/man1/flux.rst

@@ -37,6 +37,11 @@ OPTIONS
    :envvar:`FLUX_KVS_NAMESPACE` if current instance is confined to a KVS
    namespace in the parent. This option may be specified multiple times.
 
+.. option:: -r, --root
+
+   Like :option:`--parent`, but connect to the top-level, or root, instance.
+   This overrides any other uses of the :option:`--parent` option.
+
 .. option:: -v, --verbose
 
    Display command environment, and the path search for *CMD*.

src/cmd/flux.c

@@ -38,17 +38,29 @@ void setup_keydir (struct environment *env, int flags);
 static void print_environment (struct environment *env);
 static void register_builtin_subcommands (optparse_t *p);
 static void push_parent_environment (optparse_t *p, struct environment *env);
+static int current_instance_level (optparse_t *p);
 
 static struct optparse_option opts[] = {
-    { .name = "verbose",         .key = 'v', .has_arg = 0,
+    { .name = "verbose",
+      .key = 'v',
+      .has_arg = 0,
       .usage = "Be verbose about environment and command search",
     },
-    { .name = "version",         .key = 'V', .has_arg = 0,
+    { .name = "version",
+      .key = 'V',
+      .has_arg = 0,
       .usage = "Display command and component versions",
     },
-    { .name = "parent",         .key = 'p', .has_arg = 0,
+    { .name = "parent",
+      .key = 'p',
+      .has_arg = 0,
       .usage = "Set environment of parent instead of current instance",
     },
+    { .name = "root",
+      .key = 'r',
+      .has_arg = 0,
+      .usage = "Set environment of root instead of current instance",
+    },
     OPTPARSE_TABLE_END
 };
 
@@ -64,7 +76,8 @@ void usage (optparse_t *p)
     const char *val = getenv ("FLUX_CMDHELP_PATTERN");
     const char *def = default_cmdhelp_pattern (p);
 
-    if (asprintf (&help_pattern, "%s%s%s",
+    if (asprintf (&help_pattern,
+                  "%s%s%s",
                   def ? def : "",
                   val ? ":" : "",
                   val ? val : "") < 0)
@@ -121,6 +134,7 @@ int main (int argc, char *argv[])
     const char *argv0 = argv[0];
     int flags = FLUX_CONF_INSTALLED;
     int optindex;
+    int n;
 
     log_init ("flux");
 
@@ -221,9 +235,14 @@ int main (int argc, char *argv[])
 
     environment_apply (env);
 
-    /* If --parent, push parent environment for each occurrence
+    /* If --parent, push parent environment for each occurrence.
+     * If --root, act as if --parent was used instance-level times.
      */
-    for (int n = optparse_getopt (p, "parent", NULL); n > 0; n--) {
+    if (optparse_hasopt (p, "root"))
+        n = current_instance_level (p);
+    else
+        n = optparse_getopt (p, "parent", NULL);
+    while (n-- > 0) {
         push_parent_environment (p, env);
         environment_apply (env);
     }
@@ -317,8 +336,10 @@ void setup_path (struct environment *env, const char *argv0)
 /* Check for a flux-<command>.py in dir and execute it under the configured
  * PYTHON_INTERPRETER if found.
  */
-void exec_subcommand_py (bool vopt, const char *dir,
-                         int argc, char *argv[],
+void exec_subcommand_py (bool vopt,
+                         const char *dir,
+                         int argc,
+                         char *argv[],
 	                     const char *prefix)
 {
     char *path = xasprintf ("%s%s%s%s.py",
@@ -345,13 +366,16 @@ void exec_subcommand_py (bool vopt, const char *dir,
     free (path);
 }
 
-void exec_subcommand_dir (bool vopt, const char *dir, char *argv[],
-        const char *prefix)
+void exec_subcommand_dir (bool vopt,
+                          const char *dir,
+                          char *argv[],
+                          const char *prefix)
 {
     char *path = xasprintf ("%s%s%s%s",
                             dir ? dir : "",
                             dir ? "/" : "",
-                            prefix ? prefix : "", argv[0]);
+                            prefix ? prefix : "",
+                            argv[0]);
     if (vopt)
         log_msg ("trying to exec %s", path);
     execvp (path, argv); /* no return if successful */
@@ -381,7 +405,7 @@ void exec_subcommand (const char *searchpath, bool vopt, int argc, char *argv[])
     }
 }
 
-static flux_t *flux_open_internal (optparse_t *p, const char *uri)
+static flux_t *flux_open_internal (optparse_t *p)
 {
     flux_t *h = NULL;
     if ((h = optparse_get_data (p, "flux_t")))
@@ -400,11 +424,32 @@ static void flux_close_internal (optparse_t *p)
     }
 }
 
+static int current_instance_level (optparse_t *p)
+{
+    const char *s;
+    char *endptr;
+    long int l;
+    flux_t *h;
+
+    if (!(h = flux_open_internal (p)))
+        log_err_exit ("flux_open");
+
+    if (!(s = flux_attr_get (h, "instance-level")))
+        log_err_exit ("failed to get instance-level attribute");
+
+    errno = 0;
+    l = strtol (s, &endptr, 10);
+    if (errno != 0 || *endptr != '\0')
+        log_err_exit ("got invalid instance-level attribute: %s", s);
+
+    return (int) l;
+}
+
 static void push_parent_environment (optparse_t *p, struct environment *env)
 {
     const char *uri;
     const char *ns;
-    flux_t *h = flux_open_internal (p, NULL);
+    flux_t *h = flux_open_internal (p);
 
     if (h == NULL)
         log_err_exit ("flux_open");
@@ -425,11 +470,10 @@ static void push_parent_environment (optparse_t *p, struct environment *env)
     else
         environment_unset (env, "FLUX_KVS_NAMESPACE");
 
-    /*  Now close current handle and connect to parent URI.
+    /*  Now close current handle. Next call to `flux_open()` will
+     *  have FLUX_URI set to parent after environment_apply() is called.
      */
     flux_close_internal (p);
-    if (!(h = flux_open_internal (p, uri)))
-        log_err_exit ("flux_open (parent)");
 }
 
 static void print_environment (struct environment *env)
@@ -442,7 +486,7 @@ static void print_environment (struct environment *env)
 
 flux_t *builtin_get_flux_handle (optparse_t *p)
 {
-    return flux_open_internal (p, NULL);
+    return flux_open_internal (p);
 }
 
 static void register_builtin_subcommands (optparse_t *p)

t/t3100-flux-in-flux.t

@@ -50,6 +50,19 @@ test_expect_success "flux --parent --parent works in subinstance" '
 	test_cmp guest2.test.exp guest2.test
 '
 
+test_expect_success "flux --root works in subinstance" '
+	id=$(flux batch -n1 --wrap \
+		flux run flux start ${ARGS} \
+		flux --root getattr instance-level) &&
+	flux job wait-event -vt 30 $id clean &&
+	test_debug "cat flux-${id}.out" &&
+	test "$(cat flux-${id}.out)" -eq 0
+'
+
+test_expect_success 'flux --root returns current instance at depth 0' '
+	test $(flux --root getattr instance-level) -eq 0
+'
+
 test_expect_success "instance-level attribute = 0 in new standalone instance" '
 	flux start ${ARGS} flux getattr instance-level >level_new.out &&
 	echo 0 >level_new.exp &&