From 3da577280a137ff98fffd67d307372b8c881f6eb Mon Sep 17 00:00:00 2001
From: Tino Reichardt <milky-zfs@mcmilk.de>
Date: Mon, 13 Mar 2023 23:31:44 +0100
Subject: [PATCH] Add colored output to zfs list

Use a bold header row and colorize the AVAIL column based on
the used space percentage of volume.

We define these colors:
- when > 80%, use yellow
- when > 90%, use red

Reviewed-by: WHR <msl0000023508@gmail.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Ethan Coe-Renner <coerenner1@llnl.gov>
Signed-off-by: Tino Reichardt <milky-zfs@mcmilk.de>
Closes #14621
Closes #14350
---
 cmd/zfs/zfs_main.c | 30 ++++++++++++++++++++++++++++++
 man/man8/zfs.8     |  2 ++
 2 files changed, 32 insertions(+)

diff --git a/cmd/zfs/zfs_main.c b/cmd/zfs/zfs_main.c
index 02b19e7163..7191fbdf47 100644
--- a/cmd/zfs/zfs_main.c
+++ b/cmd/zfs/zfs_main.c
@@ -3474,6 +3474,8 @@ print_header(list_cbdata_t *cb)
 	boolean_t first = B_TRUE;
 	boolean_t right_justify;
 
+	color_start(ANSI_BOLD);
+
 	for (; pl != NULL; pl = pl->pl_next) {
 		if (!first) {
 			(void) printf("  ");
@@ -3500,9 +3502,31 @@ print_header(list_cbdata_t *cb)
 			(void) printf("%-*s", (int)pl->pl_width, header);
 	}
 
+	color_end();
+
 	(void) printf("\n");
 }
 
+/*
+ * Decides on the color that the avail value should be printed in.
+ * > 80% used = yellow
+ * > 90% used = red
+ */
+static const char *
+zfs_list_avail_color(zfs_handle_t *zhp)
+{
+	uint64_t used = zfs_prop_get_int(zhp, ZFS_PROP_USED);
+	uint64_t avail = zfs_prop_get_int(zhp, ZFS_PROP_AVAILABLE);
+	int percentage = (int)((double)avail / MAX(avail + used, 1) * 100);
+
+	if (percentage > 20)
+		return (NULL);
+	else if (percentage > 10)
+		return (ANSI_YELLOW);
+	else
+		return (ANSI_RED);
+}
+
 /*
  * Given a dataset and a list of fields, print out all the properties according
  * to the described layout.
@@ -3565,6 +3589,9 @@ print_dataset(zfs_handle_t *zhp, list_cbdata_t *cb)
 			right_justify = B_FALSE;
 		}
 
+		if (pl->pl_prop == ZFS_PROP_AVAILABLE)
+			color_start(zfs_list_avail_color(zhp));
+
 		/*
 		 * If this is being called in scripted mode, or if this is the
 		 * last column and it is left-justified, don't include a width
@@ -3576,6 +3603,9 @@ print_dataset(zfs_handle_t *zhp, list_cbdata_t *cb)
 			(void) printf("%*s", (int)pl->pl_width, propstr);
 		else
 			(void) printf("%-*s", (int)pl->pl_width, propstr);
+
+		if (pl->pl_prop == ZFS_PROP_AVAILABLE)
+			color_end();
 	}
 
 	(void) printf("\n");
diff --git a/man/man8/zfs.8 b/man/man8/zfs.8
index 2fc2f3166a..23220b7f3e 100644
--- a/man/man8/zfs.8
+++ b/man/man8/zfs.8
@@ -708,6 +708,8 @@ command will be undone if the share is ever unshared (like via a reboot).
 .It Sy ZFS_COLOR
 Use ANSI color in
 .Nm zfs Cm diff
+and
+.Nm zfs Cm list
 output.
 .El
 .Bl -tag -width "ZFS_MOUNT_HELPER"