weed shell: add ec.shard.unmount command (#10204)

Unmount, and optionally delete, EC volume shards from the shell, so broken
or over-replicated shards can be handled without stopping volume servers and
deleting files by hand.

Default action is unmount; --delete also removes the shard files. Targets
resolve against the live topology, with shardId:host:port to disambiguate
co-located or over-replicated shards. Dry-run by default; pass --apply.

weed/shell/command_ec_shard_unmount_test.go

@@ -0,0 +1,102 @@
+package shell
+
+import (
+	"testing"
+
+	"github.com/seaweedfs/seaweedfs/weed/storage/erasure_coding"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEcShardsFromString(t *testing.T) {
+	tests := []struct {
+		name    string
+		in      string
+		want    []*ecShard
+		wantErr bool
+	}{
+		{
+			name: "single id",
+			in:   "2",
+			want: []*ecShard{{ShardID: 2}},
+		},
+		{
+			name: "list of ids",
+			in:   "0, 3 ,5",
+			want: []*ecShard{{ShardID: 0}, {ShardID: 3}, {ShardID: 5}},
+		},
+		{
+			name: "qualified keeps host:port",
+			in:   "3@10.200.18.88:9007",
+			want: []*ecShard{{ShardID: 3, NodeAddress: "10.200.18.88:9007"}},
+		},
+		{
+			name: "mixed bare and qualified",
+			in:   "2,3@10.200.18.88:9007",
+			want: []*ecShard{{ShardID: 2}, {ShardID: 3, NodeAddress: "10.200.18.88:9007"}},
+		},
+		{
+			name:    "colon without node marker is not a shard ID",
+			in:      "3:10.200.18.88:9007",
+			wantErr: true,
+		},
+		{
+			// shard IDs beyond the default 10+4 total are valid on custom-ratio volumes.
+			name: "shard id within MaxShardCount",
+			in:   "20",
+			want: []*ecShard{{ShardID: 20}},
+		},
+		{
+			name:    "shard id at MaxShardCount is rejected",
+			in:      "32",
+			wantErr: true,
+		},
+		{
+			name:    "negative shard id",
+			in:      "-1",
+			wantErr: true,
+		},
+		{
+			// must not wrap through uint32 into a valid-looking shard ID (4294967301 -> 5)
+			name:    "out-of-range shard id does not wrap",
+			in:      "4294967301",
+			wantErr: true,
+		},
+		{
+			name:    "non-numeric shard id",
+			in:      "abc",
+			wantErr: true,
+		},
+		{
+			name:    "empty element",
+			in:      "1,,2",
+			wantErr: true,
+		},
+	}
+
+	// guard the assumption the bound test relies on
+	assert.Equal(t, uint32(32), uint32(erasure_coding.MaxShardCount))
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ecShardsFromString(tt.in)
+			if tt.wantErr {
+				assert.Error(t, err)
+				return
+			}
+			assert.NoError(t, err)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}
+
+// the printed topology form must parse back, so entries can be copied verbatim.
+func TestEcShardStringRoundTrips(t *testing.T) {
+	for _, s := range []*ecShard{
+		{ShardID: 2},
+		{ShardID: 3, NodeAddress: "10.200.18.88:9007"},
+	} {
+		got, err := ecShardsFromString(s.String())
+		assert.NoError(t, err)
+		assert.Equal(t, []*ecShard{s}, got)
+	}
+}