Fix id assignment in dot+svg output. (#224)

Previously, web interface was assuming that the ith node in
the dot graph was being assigned the id "node<i+1>".  However,
this assumption was invalid when extra nodes were inserted
into the dot output (e.g., nodelets added for allocation
profiles).  Because of this bug, node selection by clicking
in the webui graph output would sometimes pick a random
string to match against.

The problem is now fixed by manually assigning an id to
every node in the generated dot graph.  dot will propagate
this id reliably to the svg output.

Updated the golden tests to reflect the new dot output.

Extended dotgraph_test.go with an -update flag that can be
used to update golden files.  Also removed a bunch of code
duplication in the test.

internal/driver/testdata/pprof.contention.cum.files.dot

@@ -1,9 +1,9 @@
 digraph "unnamed" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "Build ID: buildid-contention" [shape=box fontsize=16 label="Build ID: buildid-contention\lComment #1\lComment #2\lType: delay\lShowing nodes accounting for 149.50ms, 100% of 149.50ms total\l"] }
-N1 [label="file3000.src\n32.77ms (21.92%)\nof 149.50ms (100%)" fontsize=20 shape=box tooltip="testdata/file3000.src (149.50ms)" color="#b20000" fillcolor="#edd5d5"]
-N2 [label="file1000.src\n51.20ms (34.25%)" fontsize=23 shape=box tooltip="testdata/file1000.src (51.20ms)" color="#b23100" fillcolor="#eddbd5"]
-N3 [label="file2000.src\n65.54ms (43.84%)\nof 75.78ms (50.68%)" fontsize=24 shape=box tooltip="testdata/file2000.src (75.78ms)" color="#b22000" fillcolor="#edd9d5"]
+N1 [label="file3000.src\n32.77ms (21.92%)\nof 149.50ms (100%)" id="node1" fontsize=20 shape=box tooltip="testdata/file3000.src (149.50ms)" color="#b20000" fillcolor="#edd5d5"]
+N2 [label="file1000.src\n51.20ms (34.25%)" id="node2" fontsize=23 shape=box tooltip="testdata/file1000.src (51.20ms)" color="#b23100" fillcolor="#eddbd5"]
+N3 [label="file2000.src\n65.54ms (43.84%)\nof 75.78ms (50.68%)" id="node3" fontsize=24 shape=box tooltip="testdata/file2000.src (75.78ms)" color="#b22000" fillcolor="#edd9d5"]
 N1 -> N3 [label=" 75.78ms" weight=51 penwidth=3 color="#b22000" tooltip="testdata/file3000.src -> testdata/file2000.src (75.78ms)" labeltooltip="testdata/file3000.src -> testdata/file2000.src (75.78ms)"]
 N1 -> N2 [label=" 40.96ms" weight=28 penwidth=2 color="#b23900" tooltip="testdata/file3000.src -> testdata/file1000.src (40.96ms)" labeltooltip="testdata/file3000.src -> testdata/file1000.src (40.96ms)"]
 N3 -> N2 [label=" 10.24ms" weight=7 color="#b29775" tooltip="testdata/file2000.src -> testdata/file1000.src (10.24ms)" labeltooltip="testdata/file2000.src -> testdata/file1000.src (10.24ms)"]

internal/driver/testdata/pprof.contention.flat.addresses.dot.focus.ignore

@@ -1,9 +1,9 @@
 digraph "unnamed" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "Build ID: buildid-contention" [shape=box fontsize=16 label="Build ID: buildid-contention\lComment #1\lComment #2\lType: delay\lActive filters:\l   focus=[X1]000\l   ignore=[X3]002\lShowing nodes accounting for 40.96ms, 27.40% of 149.50ms total\l"] }
-N1 [label="0000000000001000\nline1000\nfile1000.src:1\n40.96ms (27.40%)" fontsize=24 shape=box tooltip="0000000000001000 line1000 testdata/file1000.src:1 (40.96ms)" color="#b23900" fillcolor="#edddd5"]
-N2 [label="0000000000003001\nline3000\nfile3000.src:5\n0 of 40.96ms (27.40%)" fontsize=8 shape=box tooltip="0000000000003001 line3000 testdata/file3000.src:5 (40.96ms)" color="#b23900" fillcolor="#edddd5"]
-N3 [label="0000000000003001\nline3001\nfile3000.src:3\n0 of 40.96ms (27.40%)" fontsize=8 shape=box tooltip="0000000000003001 line3001 testdata/file3000.src:3 (40.96ms)" color="#b23900" fillcolor="#edddd5"]
+N1 [label="0000000000001000\nline1000\nfile1000.src:1\n40.96ms (27.40%)" id="node1" fontsize=24 shape=box tooltip="0000000000001000 line1000 testdata/file1000.src:1 (40.96ms)" color="#b23900" fillcolor="#edddd5"]
+N2 [label="0000000000003001\nline3000\nfile3000.src:5\n0 of 40.96ms (27.40%)" id="node2" fontsize=8 shape=box tooltip="0000000000003001 line3000 testdata/file3000.src:5 (40.96ms)" color="#b23900" fillcolor="#edddd5"]
+N3 [label="0000000000003001\nline3001\nfile3000.src:3\n0 of 40.96ms (27.40%)" id="node3" fontsize=8 shape=box tooltip="0000000000003001 line3001 testdata/file3000.src:3 (40.96ms)" color="#b23900" fillcolor="#edddd5"]
 N2 -> N3 [label=" 40.96ms\n (inline)" weight=28 penwidth=2 color="#b23900" tooltip="0000000000003001 line3000 testdata/file3000.src:5 -> 0000000000003001 line3001 testdata/file3000.src:3 (40.96ms)" labeltooltip="0000000000003001 line3000 testdata/file3000.src:5 -> 0000000000003001 line3001 testdata/file3000.src:3 (40.96ms)"]
 N3 -> N1 [label=" 40.96ms" weight=28 penwidth=2 color="#b23900" tooltip="0000000000003001 line3001 testdata/file3000.src:3 -> 0000000000001000 line1000 testdata/file1000.src:1 (40.96ms)" labeltooltip="0000000000003001 line3001 testdata/file3000.src:3 -> 0000000000001000 line1000 testdata/file1000.src:1 (40.96ms)"]
 }

internal/driver/testdata/pprof.cpu.flat.functions.call_tree.dot

@@ -1,17 +1,17 @@
 digraph "testbinary" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "File: testbinary" [shape=box fontsize=16 label="File: testbinary\lType: cpu\lDuration: 10s, Total samples = 1.12s (11.20%)\lShowing nodes accounting for 1.11s, 99.11% of 1.12s total\lDropped 3 nodes (cum <= 0.06s)\l" tooltip="testbinary"] }
-N1 [label="line1000\n1s (89.29%)" fontsize=24 shape=box tooltip="line1000 (1s)" color="#b20500" fillcolor="#edd6d5"]
-N1_0 [label = "key1:tag1\nkey2:tag1" fontsize=8 shape=box3d tooltip="1s"]
+N1 [label="line1000\n1s (89.29%)" id="node1" fontsize=24 shape=box tooltip="line1000 (1s)" color="#b20500" fillcolor="#edd6d5"]
+N1_0 [label = "key1:tag1\nkey2:tag1" id="N1_0" fontsize=8 shape=box3d tooltip="1s"]
 N1 -> N1_0 [label=" 1s" weight=100 tooltip="1s" labeltooltip="1s"]
-N2 [label="line3000\n0 of 1.12s (100%)" fontsize=8 shape=box tooltip="line3000 (1.12s)" color="#b20000" fillcolor="#edd5d5"]
-N3 [label="line3001\n0 of 1.11s (99.11%)" fontsize=8 shape=box tooltip="line3001 (1.11s)" color="#b20000" fillcolor="#edd5d5"]
-N4 [label="line1000\n0.10s (8.93%)" fontsize=14 shape=box tooltip="line1000 (0.10s)" color="#b28b62" fillcolor="#ede8e2"]
-N4_0 [label = "key1:tag2\nkey3:tag2" fontsize=8 shape=box3d tooltip="0.10s"]
+N2 [label="line3000\n0 of 1.12s (100%)" id="node2" fontsize=8 shape=box tooltip="line3000 (1.12s)" color="#b20000" fillcolor="#edd5d5"]
+N3 [label="line3001\n0 of 1.11s (99.11%)" id="node3" fontsize=8 shape=box tooltip="line3001 (1.11s)" color="#b20000" fillcolor="#edd5d5"]
+N4 [label="line1000\n0.10s (8.93%)" id="node4" fontsize=14 shape=box tooltip="line1000 (0.10s)" color="#b28b62" fillcolor="#ede8e2"]
+N4_0 [label = "key1:tag2\nkey3:tag2" id="N4_0" fontsize=8 shape=box3d tooltip="0.10s"]
 N4 -> N4_0 [label=" 0.10s" weight=100 tooltip="0.10s" labeltooltip="0.10s"]
-N5 [label="line3002\n0.01s (0.89%)\nof 1.01s (90.18%)" fontsize=10 shape=box tooltip="line3002 (1.01s)" color="#b20500" fillcolor="#edd6d5"]
-N6 [label="line2000\n0 of 1s (89.29%)" fontsize=8 shape=box tooltip="line2000 (1s)" color="#b20500" fillcolor="#edd6d5"]
-N7 [label="line2001\n0 of 1s (89.29%)" fontsize=8 shape=box tooltip="line2001 (1s)" color="#b20500" fillcolor="#edd6d5"]
+N5 [label="line3002\n0.01s (0.89%)\nof 1.01s (90.18%)" id="node5" fontsize=10 shape=box tooltip="line3002 (1.01s)" color="#b20500" fillcolor="#edd6d5"]
+N6 [label="line2000\n0 of 1s (89.29%)" id="node6" fontsize=8 shape=box tooltip="line2000 (1s)" color="#b20500" fillcolor="#edd6d5"]
+N7 [label="line2001\n0 of 1s (89.29%)" id="node7" fontsize=8 shape=box tooltip="line2001 (1s)" color="#b20500" fillcolor="#edd6d5"]
 N2 -> N3 [label=" 1.11s\n (inline)" weight=100 penwidth=5 color="#b20000" tooltip="line3000 -> line3001 (1.11s)" labeltooltip="line3000 -> line3001 (1.11s)"]
 N3 -> N5 [label=" 1.01s\n (inline)" weight=91 penwidth=5 color="#b20500" tooltip="line3001 -> line3002 (1.01s)" labeltooltip="line3001 -> line3002 (1.01s)"]
 N6 -> N7 [label=" 1s\n (inline)" weight=90 penwidth=5 color="#b20500" tooltip="line2000 -> line2001 (1s)" labeltooltip="line2000 -> line2001 (1s)"]

internal/driver/testdata/pprof.cpu.flat.functions.dot

@@ -1,16 +1,16 @@
 digraph "testbinary" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "File: testbinary" [shape=box fontsize=16 label="File: testbinary\lType: cpu\lDuration: 10s, Total samples = 1.12s (11.20%)\lShowing nodes accounting for 1.12s, 100% of 1.12s total\l" tooltip="testbinary"] }
-N1 [label="line1000\n1.10s (98.21%)" fontsize=24 shape=box tooltip="line1000 (1.10s)" color="#b20000" fillcolor="#edd5d5"]
-N1_0 [label = "key1:tag1\nkey2:tag1" fontsize=8 shape=box3d tooltip="1s"]
+N1 [label="line1000\n1.10s (98.21%)" id="node1" fontsize=24 shape=box tooltip="line1000 (1.10s)" color="#b20000" fillcolor="#edd5d5"]
+N1_0 [label = "key1:tag1\nkey2:tag1" id="N1_0" fontsize=8 shape=box3d tooltip="1s"]
 N1 -> N1_0 [label=" 1s" weight=100 tooltip="1s" labeltooltip="1s"]
-N1_1 [label = "key1:tag2\nkey3:tag2" fontsize=8 shape=box3d tooltip="0.10s"]
+N1_1 [label = "key1:tag2\nkey3:tag2" id="N1_1" fontsize=8 shape=box3d tooltip="0.10s"]
 N1 -> N1_1 [label=" 0.10s" weight=100 tooltip="0.10s" labeltooltip="0.10s"]
-N2 [label="line3000\n0 of 1.12s (100%)" fontsize=8 shape=box tooltip="line3000 (1.12s)" color="#b20000" fillcolor="#edd5d5"]
-N3 [label="line3001\n0 of 1.11s (99.11%)" fontsize=8 shape=box tooltip="line3001 (1.11s)" color="#b20000" fillcolor="#edd5d5"]
-N4 [label="line3002\n0.01s (0.89%)\nof 1.02s (91.07%)" fontsize=10 shape=box tooltip="line3002 (1.02s)" color="#b20400" fillcolor="#edd6d5"]
-N5 [label="line2001\n0.01s (0.89%)\nof 1.01s (90.18%)" fontsize=10 shape=box tooltip="line2001 (1.01s)" color="#b20500" fillcolor="#edd6d5"]
-N6 [label="line2000\n0 of 1.01s (90.18%)" fontsize=8 shape=box tooltip="line2000 (1.01s)" color="#b20500" fillcolor="#edd6d5"]
+N2 [label="line3000\n0 of 1.12s (100%)" id="node2" fontsize=8 shape=box tooltip="line3000 (1.12s)" color="#b20000" fillcolor="#edd5d5"]
+N3 [label="line3001\n0 of 1.11s (99.11%)" id="node3" fontsize=8 shape=box tooltip="line3001 (1.11s)" color="#b20000" fillcolor="#edd5d5"]
+N4 [label="line3002\n0.01s (0.89%)\nof 1.02s (91.07%)" id="node4" fontsize=10 shape=box tooltip="line3002 (1.02s)" color="#b20400" fillcolor="#edd6d5"]
+N5 [label="line2001\n0.01s (0.89%)\nof 1.01s (90.18%)" id="node5" fontsize=10 shape=box tooltip="line2001 (1.01s)" color="#b20500" fillcolor="#edd6d5"]
+N6 [label="line2000\n0 of 1.01s (90.18%)" id="node6" fontsize=8 shape=box tooltip="line2000 (1.01s)" color="#b20500" fillcolor="#edd6d5"]
 N2 -> N3 [label=" 1.11s\n (inline)" weight=100 penwidth=5 color="#b20000" tooltip="line3000 -> line3001 (1.11s)" labeltooltip="line3000 -> line3001 (1.11s)"]
 N6 -> N5 [label=" 1.01s\n (inline)" weight=91 penwidth=5 color="#b20500" tooltip="line2000 -> line2001 (1.01s)" labeltooltip="line2000 -> line2001 (1.01s)"]
 N3 -> N4 [label=" 1.01s\n (inline)" weight=91 penwidth=5 color="#b20500" tooltip="line3001 -> line3002 (1.01s)" labeltooltip="line3001 -> line3002 (1.01s)"]

internal/driver/testdata/pprof.heap.flat.inuse_space.dot.focus

@@ -1,12 +1,12 @@
 digraph "unnamed" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "Build ID: buildid" [shape=box fontsize=16 label="Build ID: buildid\lcomment\lType: inuse_space\lActive filters:\l   tagfocus=1mb:2gb\lShowing nodes accounting for 62.50MB, 63.37% of 98.63MB total\l"] }
-N1 [label="line2001\n62.50MB (63.37%)" fontsize=24 shape=box tooltip="line2001 (62.50MB)" color="#b21600" fillcolor="#edd8d5"]
-NN1_0 [label = "1.56MB" fontsize=8 shape=box3d tooltip="62.50MB"]
+N1 [label="line2001\n62.50MB (63.37%)" id="node1" fontsize=24 shape=box tooltip="line2001 (62.50MB)" color="#b21600" fillcolor="#edd8d5"]
+NN1_0 [label = "1.56MB" id="NN1_0" fontsize=8 shape=box3d tooltip="62.50MB"]
 N1 -> NN1_0 [label=" 62.50MB" weight=100 tooltip="62.50MB" labeltooltip="62.50MB"]
-N2 [label="line3000\n0 of 62.50MB (63.37%)" fontsize=8 shape=box tooltip="line3000 (62.50MB)" color="#b21600" fillcolor="#edd8d5"]
-N3 [label="line2000\n0 of 62.50MB (63.37%)" fontsize=8 shape=box tooltip="line2000 (62.50MB)" color="#b21600" fillcolor="#edd8d5"]
-N4 [label="line3002\n0 of 62.50MB (63.37%)" fontsize=8 shape=box tooltip="line3002 (62.50MB)" color="#b21600" fillcolor="#edd8d5"]
+N2 [label="line3000\n0 of 62.50MB (63.37%)" id="node2" fontsize=8 shape=box tooltip="line3000 (62.50MB)" color="#b21600" fillcolor="#edd8d5"]
+N3 [label="line2000\n0 of 62.50MB (63.37%)" id="node3" fontsize=8 shape=box tooltip="line2000 (62.50MB)" color="#b21600" fillcolor="#edd8d5"]
+N4 [label="line3002\n0 of 62.50MB (63.37%)" id="node4" fontsize=8 shape=box tooltip="line3002 (62.50MB)" color="#b21600" fillcolor="#edd8d5"]
 N3 -> N1 [label=" 62.50MB\n (inline)" weight=64 penwidth=4 color="#b21600" tooltip="line2000 -> line2001 (62.50MB)" labeltooltip="line2000 -> line2001 (62.50MB)"]
 N2 -> N4 [label=" 62.50MB\n (inline)" weight=64 penwidth=4 color="#b21600" tooltip="line3000 -> line3002 (62.50MB)" labeltooltip="line3000 -> line3002 (62.50MB)"]
 N4 -> N3 [label=" 62.50MB" weight=64 penwidth=4 color="#b21600" tooltip="line3002 -> line2000 (62.50MB)" labeltooltip="line3002 -> line2000 (62.50MB)"]

internal/driver/testdata/pprof.heap.flat.inuse_space.dot.focus.ignore

@@ -1,13 +1,13 @@
 digraph "unnamed" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "Build ID: buildid" [shape=box fontsize=16 label="Build ID: buildid\lcomment\lType: inuse_space\lActive filters:\l   tagfocus=30kb:\l   tagignore=1mb:2mb\lShowing nodes accounting for 36.13MB, 36.63% of 98.63MB total\lDropped 2 nodes (cum <= 4.93MB)\l"] }
-N1 [label="line3002\n31.25MB (31.68%)\nof 32.23MB (32.67%)" fontsize=24 shape=box tooltip="line3002 (32.23MB)" color="#b23200" fillcolor="#eddcd5"]
-NN1_0 [label = "400kB" fontsize=8 shape=box3d tooltip="31.25MB"]
+N1 [label="line3002\n31.25MB (31.68%)\nof 32.23MB (32.67%)" id="node1" fontsize=24 shape=box tooltip="line3002 (32.23MB)" color="#b23200" fillcolor="#eddcd5"]
+NN1_0 [label = "400kB" id="NN1_0" fontsize=8 shape=box3d tooltip="31.25MB"]
 N1 -> NN1_0 [label=" 31.25MB" weight=100 tooltip="31.25MB" labeltooltip="31.25MB"]
-N2 [label="line3000\n0 of 36.13MB (36.63%)" fontsize=8 shape=box tooltip="line3000 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
-N3 [label="line3001\n0 of 36.13MB (36.63%)" fontsize=8 shape=box tooltip="line3001 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
-N4 [label="line1000\n4.88MB (4.95%)" fontsize=15 shape=box tooltip="line1000 (4.88MB)" color="#b2a086" fillcolor="#edeae7"]
-NN4_0 [label = "200kB" fontsize=8 shape=box3d tooltip="3.91MB"]
+N2 [label="line3000\n0 of 36.13MB (36.63%)" id="node2" fontsize=8 shape=box tooltip="line3000 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
+N3 [label="line3001\n0 of 36.13MB (36.63%)" id="node3" fontsize=8 shape=box tooltip="line3001 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
+N4 [label="line1000\n4.88MB (4.95%)" id="node4" fontsize=15 shape=box tooltip="line1000 (4.88MB)" color="#b2a086" fillcolor="#edeae7"]
+NN4_0 [label = "200kB" id="NN4_0" fontsize=8 shape=box3d tooltip="3.91MB"]
 N4 -> NN4_0 [label=" 3.91MB" weight=100 tooltip="3.91MB" labeltooltip="3.91MB"]
 N2 -> N3 [label=" 36.13MB\n (inline)" weight=37 penwidth=2 color="#b22e00" tooltip="line3000 -> line3001 (36.13MB)" labeltooltip="line3000 -> line3001 (36.13MB)"]
 N3 -> N1 [label=" 32.23MB\n (inline)" weight=33 penwidth=2 color="#b23200" tooltip="line3001 -> line3002 (32.23MB)" labeltooltip="line3001 -> line3002 (32.23MB)"]

internal/driver/testdata/pprof.heap.flat.lines.dot.focus

@@ -1,16 +1,16 @@
 digraph "unnamed" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "Build ID: buildid" [shape=box fontsize=16 label="Build ID: buildid\lcomment\lType: inuse_space\lActive filters:\l   focus=[12]00\lShowing nodes accounting for 67.38MB, 68.32% of 98.63MB total\l"] }
-N1 [label="line3000\nfile3000.src:4\n0 of 67.38MB (68.32%)" fontsize=8 shape=box tooltip="line3000 testdata/file3000.src:4 (67.38MB)" color="#b21300" fillcolor="#edd7d5"]
-N2 [label="line2001\nfile2000.src:2\n62.50MB (63.37%)\nof 63.48MB (64.36%)" fontsize=24 shape=box tooltip="line2001 testdata/file2000.src:2 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
-NN2_0 [label = "1.56MB" fontsize=8 shape=box3d tooltip="62.50MB"]
+N1 [label="line3000\nfile3000.src:4\n0 of 67.38MB (68.32%)" id="node1" fontsize=8 shape=box tooltip="line3000 testdata/file3000.src:4 (67.38MB)" color="#b21300" fillcolor="#edd7d5"]
+N2 [label="line2001\nfile2000.src:2\n62.50MB (63.37%)\nof 63.48MB (64.36%)" id="node2" fontsize=24 shape=box tooltip="line2001 testdata/file2000.src:2 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
+NN2_0 [label = "1.56MB" id="NN2_0" fontsize=8 shape=box3d tooltip="62.50MB"]
 N2 -> NN2_0 [label=" 62.50MB" weight=100 tooltip="62.50MB" labeltooltip="62.50MB"]
-N3 [label="line1000\nfile1000.src:1\n4.88MB (4.95%)" fontsize=13 shape=box tooltip="line1000 testdata/file1000.src:1 (4.88MB)" color="#b2a086" fillcolor="#edeae7"]
-NN3_0 [label = "200kB" fontsize=8 shape=box3d tooltip="3.91MB"]
+N3 [label="line1000\nfile1000.src:1\n4.88MB (4.95%)" id="node3" fontsize=13 shape=box tooltip="line1000 testdata/file1000.src:1 (4.88MB)" color="#b2a086" fillcolor="#edeae7"]
+NN3_0 [label = "200kB" id="NN3_0" fontsize=8 shape=box3d tooltip="3.91MB"]
 N3 -> NN3_0 [label=" 3.91MB" weight=100 tooltip="3.91MB" labeltooltip="3.91MB"]
-N4 [label="line3002\nfile3000.src:3\n0 of 63.48MB (64.36%)" fontsize=8 shape=box tooltip="line3002 testdata/file3000.src:3 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
-N5 [label="line3001\nfile3000.src:2\n0 of 4.88MB (4.95%)" fontsize=8 shape=box tooltip="line3001 testdata/file3000.src:2 (4.88MB)" color="#b2a086" fillcolor="#edeae7"]
-N6 [label="line2000\nfile2000.src:3\n0 of 63.48MB (64.36%)" fontsize=8 shape=box tooltip="line2000 testdata/file2000.src:3 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
+N4 [label="line3002\nfile3000.src:3\n0 of 63.48MB (64.36%)" id="node4" fontsize=8 shape=box tooltip="line3002 testdata/file3000.src:3 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
+N5 [label="line3001\nfile3000.src:2\n0 of 4.88MB (4.95%)" id="node5" fontsize=8 shape=box tooltip="line3001 testdata/file3000.src:2 (4.88MB)" color="#b2a086" fillcolor="#edeae7"]
+N6 [label="line2000\nfile2000.src:3\n0 of 63.48MB (64.36%)" id="node6" fontsize=8 shape=box tooltip="line2000 testdata/file2000.src:3 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
 N6 -> N2 [label=" 63.48MB\n (inline)" weight=65 penwidth=4 color="#b21600" tooltip="line2000 testdata/file2000.src:3 -> line2001 testdata/file2000.src:2 (63.48MB)" labeltooltip="line2000 testdata/file2000.src:3 -> line2001 testdata/file2000.src:2 (63.48MB)"]
 N4 -> N6 [label=" 63.48MB" weight=65 penwidth=4 color="#b21600" tooltip="line3002 testdata/file3000.src:3 -> line2000 testdata/file2000.src:3 (63.48MB)" labeltooltip="line3002 testdata/file3000.src:3 -> line2000 testdata/file2000.src:3 (63.48MB)"]
 N1 -> N4 [label=" 62.50MB\n (inline)" weight=64 penwidth=4 color="#b21600" tooltip="line3000 testdata/file3000.src:4 -> line3002 testdata/file3000.src:3 (62.50MB)" labeltooltip="line3000 testdata/file3000.src:4 -> line3002 testdata/file3000.src:3 (62.50MB)"]

internal/driver/testdata/pprof.heap_alloc.flat.alloc_space.dot

@@ -1,11 +1,11 @@
 digraph "unnamed" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "Build ID: buildid" [shape=box fontsize=16 label="Build ID: buildid\lcomment\lType: alloc_space\lActive filters:\l   tagshow=[2]00\lShowing nodes accounting for 93.75MB, 95.05% of 98.63MB total\lDropped 1 node (cum <= 4.93MB)\l"] }
-N1 [label="line3002\n31.25MB (31.68%)\nof 94.73MB (96.04%)" fontsize=20 shape=box tooltip="line3002 (94.73MB)" color="#b20200" fillcolor="#edd5d5"]
-N2 [label="line3000\n0 of 98.63MB (100%)" fontsize=8 shape=box tooltip="line3000 (98.63MB)" color="#b20000" fillcolor="#edd5d5"]
-N3 [label="line2001\n62.50MB (63.37%)\nof 63.48MB (64.36%)" fontsize=24 shape=box tooltip="line2001 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
-N4 [label="line2000\n0 of 63.48MB (64.36%)" fontsize=8 shape=box tooltip="line2000 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
-N5 [label="line3001\n0 of 36.13MB (36.63%)" fontsize=8 shape=box tooltip="line3001 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
+N1 [label="line3002\n31.25MB (31.68%)\nof 94.73MB (96.04%)" id="node1" fontsize=20 shape=box tooltip="line3002 (94.73MB)" color="#b20200" fillcolor="#edd5d5"]
+N2 [label="line3000\n0 of 98.63MB (100%)" id="node2" fontsize=8 shape=box tooltip="line3000 (98.63MB)" color="#b20000" fillcolor="#edd5d5"]
+N3 [label="line2001\n62.50MB (63.37%)\nof 63.48MB (64.36%)" id="node3" fontsize=24 shape=box tooltip="line2001 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
+N4 [label="line2000\n0 of 63.48MB (64.36%)" id="node4" fontsize=8 shape=box tooltip="line2000 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
+N5 [label="line3001\n0 of 36.13MB (36.63%)" id="node5" fontsize=8 shape=box tooltip="line3001 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
 N4 -> N3 [label=" 63.48MB\n (inline)" weight=65 penwidth=4 color="#b21600" tooltip="line2000 -> line2001 (63.48MB)" labeltooltip="line2000 -> line2001 (63.48MB)"]
 N1 -> N4 [label=" 63.48MB" weight=65 penwidth=4 color="#b21600" tooltip="line3002 -> line2000 (63.48MB)" labeltooltip="line3002 -> line2000 (63.48MB)"]
 N2 -> N1 [label=" 62.50MB\n (inline)" weight=64 penwidth=4 color="#b21600" tooltip="line3000 -> line3002 (62.50MB)" labeltooltip="line3000 -> line3002 (62.50MB)"]

internal/driver/testdata/pprof.heap_alloc.flat.alloc_space.dot.focus

@@ -1,15 +1,15 @@
 digraph "unnamed" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "Build ID: buildid" [shape=box fontsize=16 label="Build ID: buildid\lcomment\lType: alloc_space\lActive filters:\l   focus=[234]00\lShowing nodes accounting for 93.75MB, 95.05% of 98.63MB total\lDropped 1 node (cum <= 4.93MB)\l"] }
-N1 [label="line3002\n31.25MB (31.68%)\nof 94.73MB (96.04%)" fontsize=20 shape=box tooltip="line3002 (94.73MB)" color="#b20200" fillcolor="#edd5d5"]
-NN1_0 [label = "400kB" fontsize=8 shape=box3d tooltip="31.25MB"]
+N1 [label="line3002\n31.25MB (31.68%)\nof 94.73MB (96.04%)" id="node1" fontsize=20 shape=box tooltip="line3002 (94.73MB)" color="#b20200" fillcolor="#edd5d5"]
+NN1_0 [label = "400kB" id="NN1_0" fontsize=8 shape=box3d tooltip="31.25MB"]
 N1 -> NN1_0 [label=" 31.25MB" weight=100 tooltip="31.25MB" labeltooltip="31.25MB"]
-N2 [label="line3000\n0 of 98.63MB (100%)" fontsize=8 shape=box tooltip="line3000 (98.63MB)" color="#b20000" fillcolor="#edd5d5"]
-N3 [label="line2001\n62.50MB (63.37%)\nof 63.48MB (64.36%)" fontsize=24 shape=box tooltip="line2001 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
-NN3_0 [label = "1.56MB" fontsize=8 shape=box3d tooltip="62.50MB"]
+N2 [label="line3000\n0 of 98.63MB (100%)" id="node2" fontsize=8 shape=box tooltip="line3000 (98.63MB)" color="#b20000" fillcolor="#edd5d5"]
+N3 [label="line2001\n62.50MB (63.37%)\nof 63.48MB (64.36%)" id="node3" fontsize=24 shape=box tooltip="line2001 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
+NN3_0 [label = "1.56MB" id="NN3_0" fontsize=8 shape=box3d tooltip="62.50MB"]
 N3 -> NN3_0 [label=" 62.50MB" weight=100 tooltip="62.50MB" labeltooltip="62.50MB"]
-N4 [label="line2000\n0 of 63.48MB (64.36%)" fontsize=8 shape=box tooltip="line2000 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
-N5 [label="line3001\n0 of 36.13MB (36.63%)" fontsize=8 shape=box tooltip="line3001 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
+N4 [label="line2000\n0 of 63.48MB (64.36%)" id="node4" fontsize=8 shape=box tooltip="line2000 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
+N5 [label="line3001\n0 of 36.13MB (36.63%)" id="node5" fontsize=8 shape=box tooltip="line3001 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
 N4 -> N3 [label=" 63.48MB\n (inline)" weight=65 penwidth=4 color="#b21600" tooltip="line2000 -> line2001 (63.48MB)" labeltooltip="line2000 -> line2001 (63.48MB)"]
 N1 -> N4 [label=" 63.48MB" weight=65 penwidth=4 color="#b21600" tooltip="line3002 -> line2000 (63.48MB)" labeltooltip="line3002 -> line2000 (63.48MB)" minlen=2]
 N2 -> N1 [label=" 62.50MB\n (inline)" weight=64 penwidth=4 color="#b21600" tooltip="line3000 -> line3002 (62.50MB)" labeltooltip="line3000 -> line3002 (62.50MB)"]

internal/driver/testdata/pprof.heap_alloc.flat.alloc_space.dot.hide

@@ -1,11 +1,11 @@
 digraph "unnamed" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "Build ID: buildid" [shape=box fontsize=16 label="Build ID: buildid\lcomment\lType: alloc_space\lActive filters:\l   hide=line.*1?23?\lShowing nodes accounting for 93.75MB, 95.05% of 98.63MB total\lDropped 1 node (cum <= 4.93MB)\l"] }
-N1 [label="line3000\n62.50MB (63.37%)\nof 98.63MB (100%)" fontsize=24 shape=box tooltip="line3000 (98.63MB)" color="#b20000" fillcolor="#edd5d5"]
-NN1_0 [label = "1.56MB" fontsize=8 shape=box3d tooltip="62.50MB"]
+N1 [label="line3000\n62.50MB (63.37%)\nof 98.63MB (100%)" id="node1" fontsize=24 shape=box tooltip="line3000 (98.63MB)" color="#b20000" fillcolor="#edd5d5"]
+NN1_0 [label = "1.56MB" id="NN1_0" fontsize=8 shape=box3d tooltip="62.50MB"]
 N1 -> NN1_0 [label=" 62.50MB" weight=100 tooltip="62.50MB" labeltooltip="62.50MB"]
-N2 [label="line3001\n31.25MB (31.68%)\nof 36.13MB (36.63%)" fontsize=20 shape=box tooltip="line3001 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
-NN2_0 [label = "400kB" fontsize=8 shape=box3d tooltip="31.25MB"]
+N2 [label="line3001\n31.25MB (31.68%)\nof 36.13MB (36.63%)" id="node2" fontsize=20 shape=box tooltip="line3001 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
+NN2_0 [label = "400kB" id="NN2_0" fontsize=8 shape=box3d tooltip="31.25MB"]
 N2 -> NN2_0 [label=" 31.25MB" weight=100 tooltip="31.25MB" labeltooltip="31.25MB"]
 N1 -> N2 [label=" 36.13MB\n (inline)" weight=37 penwidth=2 color="#b22e00" tooltip="line3000 -> line3001 (36.13MB)" labeltooltip="line3000 -> line3001 (36.13MB)" minlen=2]
 }

internal/driver/testdata/pprof.heap_sizetags.dot

@@ -1,27 +1,27 @@
 digraph "unnamed" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "Build ID: buildid" [shape=box fontsize=16 label="Build ID: buildid\lcomment\lType: inuse_space\lShowing nodes accounting for 93.75MB, 95.05% of 98.63MB total\lDropped 1 node (cum <= 4.93MB)\l"] }
-N1 [label="line3002\n31.25MB (31.68%)\nof 94.73MB (96.04%)" fontsize=20 shape=box tooltip="line3002 (94.73MB)" color="#b20200" fillcolor="#edd5d5"]
-NN1_0 [label = "16B..64B" fontsize=8 shape=box3d tooltip="93.75MB"]
+N1 [label="line3002\n31.25MB (31.68%)\nof 94.73MB (96.04%)" id="node1" fontsize=20 shape=box tooltip="line3002 (94.73MB)" color="#b20200" fillcolor="#edd5d5"]
+NN1_0 [label = "16B..64B" id="NN1_0" fontsize=8 shape=box3d tooltip="93.75MB"]
 N1 -> NN1_0 [label=" 93.75MB" weight=100 tooltip="93.75MB" labeltooltip="93.75MB"]
-NN1_1 [label = "2B..8B" fontsize=8 shape=box3d tooltip="93.75MB"]
+NN1_1 [label = "2B..8B" id="NN1_1" fontsize=8 shape=box3d tooltip="93.75MB"]
 N1 -> NN1_1 [label=" 93.75MB" weight=100 tooltip="93.75MB" labeltooltip="93.75MB"]
-NN1_2 [label = "256B..1.56MB" fontsize=8 shape=box3d tooltip="62.50MB"]
+NN1_2 [label = "256B..1.56MB" id="NN1_2" fontsize=8 shape=box3d tooltip="62.50MB"]
 N1 -> NN1_2 [label=" 62.50MB" weight=100 tooltip="62.50MB" labeltooltip="62.50MB"]
-NN1_3 [label = "128B" fontsize=8 shape=box3d tooltip="31.25MB"]
+NN1_3 [label = "128B" id="NN1_3" fontsize=8 shape=box3d tooltip="31.25MB"]
 N1 -> NN1_3 [label=" 31.25MB" weight=100 tooltip="31.25MB" labeltooltip="31.25MB"]
-N2 [label="line3000\n0 of 98.63MB (100%)" fontsize=8 shape=box tooltip="line3000 (98.63MB)" color="#b20000" fillcolor="#edd5d5"]
-N3 [label="line2001\n62.50MB (63.37%)\nof 63.48MB (64.36%)" fontsize=24 shape=box tooltip="line2001 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
-NN3_0 [label = "16B..64B" fontsize=8 shape=box3d tooltip="190.43MB"]
+N2 [label="line3000\n0 of 98.63MB (100%)" id="node2" fontsize=8 shape=box tooltip="line3000 (98.63MB)" color="#b20000" fillcolor="#edd5d5"]
+N3 [label="line2001\n62.50MB (63.37%)\nof 63.48MB (64.36%)" id="node3" fontsize=24 shape=box tooltip="line2001 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
+NN3_0 [label = "16B..64B" id="NN3_0" fontsize=8 shape=box3d tooltip="190.43MB"]
 N3 -> NN3_0 [label=" 190.43MB" weight=100 tooltip="190.43MB" labeltooltip="190.43MB" style="dotted"]
-NN3_1 [label = "2B..8B" fontsize=8 shape=box3d tooltip="190.43MB"]
+NN3_1 [label = "2B..8B" id="NN3_1" fontsize=8 shape=box3d tooltip="190.43MB"]
 N3 -> NN3_1 [label=" 190.43MB" weight=100 tooltip="190.43MB" labeltooltip="190.43MB" style="dotted"]
-NN3_2 [label = "256B..1.56MB" fontsize=8 shape=box3d tooltip="125.98MB"]
+NN3_2 [label = "256B..1.56MB" id="NN3_2" fontsize=8 shape=box3d tooltip="125.98MB"]
 N3 -> NN3_2 [label=" 125.98MB" weight=100 tooltip="125.98MB" labeltooltip="125.98MB" style="dotted"]
-NN3_3 [label = "128B" fontsize=8 shape=box3d tooltip="63.48MB"]
+NN3_3 [label = "128B" id="NN3_3" fontsize=8 shape=box3d tooltip="63.48MB"]
 N3 -> NN3_3 [label=" 63.48MB" weight=100 tooltip="63.48MB" labeltooltip="63.48MB" style="dotted"]
-N4 [label="line2000\n0 of 63.48MB (64.36%)" fontsize=8 shape=box tooltip="line2000 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
-N5 [label="line3001\n0 of 36.13MB (36.63%)" fontsize=8 shape=box tooltip="line3001 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
+N4 [label="line2000\n0 of 63.48MB (64.36%)" id="node4" fontsize=8 shape=box tooltip="line2000 (63.48MB)" color="#b21600" fillcolor="#edd8d5"]
+N5 [label="line3001\n0 of 36.13MB (36.63%)" id="node5" fontsize=8 shape=box tooltip="line3001 (36.13MB)" color="#b22e00" fillcolor="#eddbd5"]
 N4 -> N3 [label=" 63.48MB\n (inline)" weight=65 penwidth=4 color="#b21600" tooltip="line2000 -> line2001 (63.48MB)" labeltooltip="line2000 -> line2001 (63.48MB)"]
 N1 -> N4 [label=" 63.48MB" weight=65 penwidth=4 color="#b21600" tooltip="line3002 -> line2000 (63.48MB)" labeltooltip="line3002 -> line2000 (63.48MB)" minlen=2]
 N2 -> N1 [label=" 62.50MB\n (inline)" weight=64 penwidth=4 color="#b21600" tooltip="line3000 -> line3002 (62.50MB)" labeltooltip="line3000 -> line3002 (62.50MB)"]

internal/graph/dotgraph.go

@@ -186,8 +186,8 @@ func (b *builder) addNode(node *Node, nodeID int, maxFlat float64) {
 	}
 
 	// Create DOT attribute for node.
-	attr := fmt.Sprintf(`label="%s" fontsize=%d shape=%s tooltip="%s (%s)" color="%s" fillcolor="%s"`,
-		label, fontSize, shape, node.Info.PrintableName(), cumValue,
+	attr := fmt.Sprintf(`label="%s" id="node%d" fontsize=%d shape=%s tooltip="%s (%s)" color="%s" fillcolor="%s"`,
+		label, nodeID, fontSize, shape, node.Info.PrintableName(), cumValue,
 		dotColor(float64(node.CumValue())/float64(abs64(b.config.Total)), false),
 		dotColor(float64(node.CumValue())/float64(abs64(b.config.Total)), true))
 
@@ -247,7 +247,7 @@ func (b *builder) addNodelets(node *Node, nodeID int) bool {
 			continue
 		}
 		weight := b.config.FormatValue(w)
-		nodelets += fmt.Sprintf(`N%d_%d [label = "%s" fontsize=8 shape=box3d tooltip="%s"]`+"\n", nodeID, i, t.Name, weight)
+		nodelets += fmt.Sprintf(`N%d_%d [label = "%s" id="N%d_%d" fontsize=8 shape=box3d tooltip="%s"]`+"\n", nodeID, i, t.Name, nodeID, i, weight)
 		nodelets += fmt.Sprintf(`N%d -> N%d_%d [label=" %s" weight=100 tooltip="%s" labeltooltip="%s"]`+"\n", nodeID, nodeID, i, weight, weight, weight)
 		if nts := lnts[t.Name]; nts != nil {
 			nodelets += b.numericNodelets(nts, maxNodelets, flatTags, fmt.Sprintf(`N%d_%d`, nodeID, i))
@@ -274,7 +274,7 @@ func (b *builder) numericNodelets(nts []*Tag, maxNumNodelets int, flatTags bool,
 		}
 		if w != 0 {
 			weight := b.config.FormatValue(w)
-			nodelets += fmt.Sprintf(`N%s_%d [label = "%s" fontsize=8 shape=box3d tooltip="%s"]`+"\n", source, j, t.Name, weight)
+			nodelets += fmt.Sprintf(`N%s_%d [label = "%s" id="N%s_%d" fontsize=8 shape=box3d tooltip="%s"]`+"\n", source, j, t.Name, source, j, weight)
 			nodelets += fmt.Sprintf(`%s -> N%s_%d [label=" %s" weight=100 tooltip="%s" labeltooltip="%s"%s]`+"\n", source, source, j, weight, weight, weight, attr)
 		}
 	}

internal/graph/dotgraph_test.go

@@ -16,8 +16,10 @@ package graph
 
 import (
 	"bytes"
+	"flag"
 	"fmt"
 	"io/ioutil"
+	"path/filepath"
 	"reflect"
 	"strconv"
 	"strings"
@@ -26,7 +28,7 @@ import (
 	"github.com/google/pprof/internal/proftest"
 )
 
-const path = "testdata/"
+var updateFlag = flag.Bool("update", false, "Update the golden files")
 
 func TestComposeWithStandardGraph(t *testing.T) {
 	g := baseGraph()
@@ -35,12 +37,7 @@ func TestComposeWithStandardGraph(t *testing.T) {
 	var buf bytes.Buffer
 	ComposeDot(&buf, g, a, c)
 
-	want, err := ioutil.ReadFile(path + "compose1.dot")
-	if err != nil {
-		t.Fatalf("error reading test file: %v", err)
-	}
-
-	compareGraphs(t, buf.Bytes(), want)
+	compareGraphs(t, buf.Bytes(), "compose1.dot")
 }
 
 func TestComposeWithNodeAttributesAndZeroFlat(t *testing.T) {
@@ -64,12 +61,7 @@ func TestComposeWithNodeAttributesAndZeroFlat(t *testing.T) {
 	var buf bytes.Buffer
 	ComposeDot(&buf, g, a, c)
 
-	want, err := ioutil.ReadFile(path + "compose2.dot")
-	if err != nil {
-		t.Fatalf("error reading test file: %v", err)
-	}
-
-	compareGraphs(t, buf.Bytes(), want)
+	compareGraphs(t, buf.Bytes(), "compose2.dot")
 }
 
 func TestComposeWithTagsAndResidualEdge(t *testing.T) {
@@ -97,12 +89,7 @@ func TestComposeWithTagsAndResidualEdge(t *testing.T) {
 	var buf bytes.Buffer
 	ComposeDot(&buf, g, a, c)
 
-	want, err := ioutil.ReadFile(path + "compose3.dot")
-	if err != nil {
-		t.Fatalf("error reading test file: %v", err)
-	}
-
-	compareGraphs(t, buf.Bytes(), want)
+	compareGraphs(t, buf.Bytes(), "compose3.dot")
 }
 
 func TestComposeWithNestedTags(t *testing.T) {
@@ -127,12 +114,7 @@ func TestComposeWithNestedTags(t *testing.T) {
 	var buf bytes.Buffer
 	ComposeDot(&buf, g, a, c)
 
-	want, err := ioutil.ReadFile(path + "compose5.dot")
-	if err != nil {
-		t.Fatalf("error reading test file: %v", err)
-	}
-
-	compareGraphs(t, buf.Bytes(), want)
+	compareGraphs(t, buf.Bytes(), "compose5.dot")
 }
 
 func TestComposeWithEmptyGraph(t *testing.T) {
@@ -142,12 +124,7 @@ func TestComposeWithEmptyGraph(t *testing.T) {
 	var buf bytes.Buffer
 	ComposeDot(&buf, g, a, c)
 
-	want, err := ioutil.ReadFile(path + "compose4.dot")
-	if err != nil {
-		t.Fatalf("error reading test file: %v", err)
-	}
-
-	compareGraphs(t, buf.Bytes(), want)
+	compareGraphs(t, buf.Bytes(), "compose4.dot")
 }
 
 func TestComposeWithStandardGraphAndURL(t *testing.T) {
@@ -158,12 +135,7 @@ func TestComposeWithStandardGraphAndURL(t *testing.T) {
 	var buf bytes.Buffer
 	ComposeDot(&buf, g, a, c)
 
-	want, err := ioutil.ReadFile(path + "compose6.dot")
-	if err != nil {
-		t.Fatalf("error reading test file: %v", err)
-	}
-
-	compareGraphs(t, buf.Bytes(), want)
+	compareGraphs(t, buf.Bytes(), "compose6.dot")
 }
 
 func baseGraph() *Graph {
@@ -215,13 +187,25 @@ func baseAttrsAndConfig() (*DotAttributes, *DotConfig) {
 	return a, c
 }
 
-func compareGraphs(t *testing.T, got, want []byte) {
+func compareGraphs(t *testing.T, got []byte, wantFile string) {
+	wantFile = filepath.Join("testdata", wantFile)
+	want, err := ioutil.ReadFile(wantFile)
+	if err != nil {
+		t.Fatalf("error reading test file %s: %v", wantFile, err)
+	}
+
 	if string(got) != string(want) {
 		d, err := proftest.Diff(got, want)
 		if err != nil {
 			t.Fatalf("error finding diff: %v", err)
 		}
 		t.Errorf("Compose incorrectly wrote %s", string(d))
+		if *updateFlag {
+			err := ioutil.WriteFile(wantFile, got, 0644)
+			if err != nil {
+				t.Errorf("failed to update the golden file %q: %v", wantFile, err)
+			}
+		}
 	}
 }
 

internal/graph/testdata/compose1.dot

@@ -1,7 +1,7 @@
 digraph "testtitle" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "label1" [shape=box fontsize=16 label="label1\llabel2\l" tooltip="testtitle"] }
-N1 [label="src\n10 (10.00%)\nof 25 (25.00%)" fontsize=22 shape=box tooltip="src (25)" color="#b23c00" fillcolor="#edddd5"]
-N2 [label="dest\n15 (15.00%)\nof 25 (25.00%)" fontsize=24 shape=box tooltip="dest (25)" color="#b23c00" fillcolor="#edddd5"]
+N1 [label="src\n10 (10.00%)\nof 25 (25.00%)" id="node1" fontsize=22 shape=box tooltip="src (25)" color="#b23c00" fillcolor="#edddd5"]
+N2 [label="dest\n15 (15.00%)\nof 25 (25.00%)" id="node2" fontsize=24 shape=box tooltip="dest (25)" color="#b23c00" fillcolor="#edddd5"]
 N1 -> N2 [label=" 10" weight=11 color="#b28559" tooltip="src -> dest (10)" labeltooltip="src -> dest (10)"]
 }

internal/graph/testdata/compose2.dot

@@ -1,7 +1,7 @@
 digraph "testtitle" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "label1" [shape=box fontsize=16 label="label1\llabel2\l" tooltip="testtitle"] }
-N1 [label="SRC10 (10.00%)\nof 25 (25.00%)" fontsize=24 shape=folder tooltip="src (25)" color="#b23c00" fillcolor="#edddd5" style="bold,filled" peripheries=2 URL="www.google.com" target="_blank"]
-N2 [label="dest\n0 of 25 (25.00%)" fontsize=8 shape=box tooltip="dest (25)" color="#b23c00" fillcolor="#edddd5"]
+N1 [label="SRC10 (10.00%)\nof 25 (25.00%)" id="node1" fontsize=24 shape=folder tooltip="src (25)" color="#b23c00" fillcolor="#edddd5" style="bold,filled" peripheries=2 URL="www.google.com" target="_blank"]
+N2 [label="dest\n0 of 25 (25.00%)" id="node2" fontsize=8 shape=box tooltip="dest (25)" color="#b23c00" fillcolor="#edddd5"]
 N1 -> N2 [label=" 10" weight=11 color="#b28559" tooltip="src -> dest (10)" labeltooltip="src -> dest (10)"]
 }

internal/graph/testdata/compose3.dot

@@ -1,11 +1,11 @@
 digraph "testtitle" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "label1" [shape=box fontsize=16 label="label1\llabel2\l" tooltip="testtitle"] }
-N1 [label="src\n10 (10.00%)\nof 25 (25.00%)" fontsize=22 shape=box tooltip="src (25)" color="#b23c00" fillcolor="#edddd5"]
-N1_0 [label = "tag1" fontsize=8 shape=box3d tooltip="10"]
+N1 [label="src\n10 (10.00%)\nof 25 (25.00%)" id="node1" fontsize=22 shape=box tooltip="src (25)" color="#b23c00" fillcolor="#edddd5"]
+N1_0 [label = "tag1" id="N1_0" fontsize=8 shape=box3d tooltip="10"]
 N1 -> N1_0 [label=" 10" weight=100 tooltip="10" labeltooltip="10"]
-NN1_0 [label = "tag2" fontsize=8 shape=box3d tooltip="20"]
+NN1_0 [label = "tag2" id="NN1_0" fontsize=8 shape=box3d tooltip="20"]
 N1 -> NN1_0 [label=" 20" weight=100 tooltip="20" labeltooltip="20"]
-N2 [label="dest\n15 (15.00%)\nof 25 (25.00%)" fontsize=24 shape=box tooltip="dest (25)" color="#b23c00" fillcolor="#edddd5"]
+N2 [label="dest\n15 (15.00%)\nof 25 (25.00%)" id="node2" fontsize=24 shape=box tooltip="dest (25)" color="#b23c00" fillcolor="#edddd5"]
 N1 -> N2 [label=" 10" weight=11 color="#b28559" tooltip="src ... dest (10)" labeltooltip="src ... dest (10)" style="dotted" minlen=2]
 }

internal/graph/testdata/compose5.dot

@@ -1,11 +1,11 @@
 digraph "testtitle" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "label1" [shape=box fontsize=16 label="label1\llabel2\l" tooltip="testtitle"] }
-N1 [label="src\n10 (10.00%)\nof 25 (25.00%)" fontsize=22 shape=box tooltip="src (25)" color="#b23c00" fillcolor="#edddd5"]
-N1_0 [label = "tag1" fontsize=8 shape=box3d tooltip="10"]
+N1 [label="src\n10 (10.00%)\nof 25 (25.00%)" id="node1" fontsize=22 shape=box tooltip="src (25)" color="#b23c00" fillcolor="#edddd5"]
+N1_0 [label = "tag1" id="N1_0" fontsize=8 shape=box3d tooltip="10"]
 N1 -> N1_0 [label=" 10" weight=100 tooltip="10" labeltooltip="10"]
-NN1_0_0 [label = "tag2" fontsize=8 shape=box3d tooltip="20"]
+NN1_0_0 [label = "tag2" id="NN1_0_0" fontsize=8 shape=box3d tooltip="20"]
 N1_0 -> NN1_0_0 [label=" 20" weight=100 tooltip="20" labeltooltip="20"]
-N2 [label="dest\n15 (15.00%)\nof 25 (25.00%)" fontsize=24 shape=box tooltip="dest (25)" color="#b23c00" fillcolor="#edddd5"]
+N2 [label="dest\n15 (15.00%)\nof 25 (25.00%)" id="node2" fontsize=24 shape=box tooltip="dest (25)" color="#b23c00" fillcolor="#edddd5"]
 N1 -> N2 [label=" 10" weight=11 color="#b28559" tooltip="src -> dest (10)" labeltooltip="src -> dest (10)" minlen=2]
 }

internal/graph/testdata/compose6.dot

@@ -1,7 +1,7 @@
 digraph "testtitle" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "label1" [shape=box fontsize=16 label="label1\llabel2\l" URL="http://example.com" target="_blank" tooltip="testtitle"] }
-N1 [label="src\n10 (10.00%)\nof 25 (25.00%)" fontsize=22 shape=box tooltip="src (25)" color="#b23c00" fillcolor="#edddd5"]
-N2 [label="dest\n15 (15.00%)\nof 25 (25.00%)" fontsize=24 shape=box tooltip="dest (25)" color="#b23c00" fillcolor="#edddd5"]
+N1 [label="src\n10 (10.00%)\nof 25 (25.00%)" id="node1" fontsize=22 shape=box tooltip="src (25)" color="#b23c00" fillcolor="#edddd5"]
+N2 [label="dest\n15 (15.00%)\nof 25 (25.00%)" id="node2" fontsize=24 shape=box tooltip="dest (25)" color="#b23c00" fillcolor="#edddd5"]
 N1 -> N2 [label=" 10" weight=11 color="#b28559" tooltip="src -> dest (10)" labeltooltip="src -> dest (10)"]
 }

internal/report/testdata/source.dot

@@ -1,13 +1,13 @@
 digraph "unnamed" {
 node [style=filled fillcolor="#f8f8f8"]
 subgraph cluster_L { "Duration: 10s, Total samples = 11111 " [shape=box fontsize=16 label="Duration: 10s, Total samples = 11111 \lShowing nodes accounting for 11111, 100% of 11111 total\l"] }
-N1 [label="tee\nsource2:8\n10000 (90.00%)" fontsize=24 shape=box tooltip="tee testdata/source2:8 (10000)" color="#b20500" fillcolor="#edd6d5"]
-N2 [label="main\nsource1:2\n1 (0.009%)\nof 11111 (100%)" fontsize=9 shape=box tooltip="main testdata/source1:2 (11111)" color="#b20000" fillcolor="#edd5d5"]
-N3 [label="tee\nsource2:2\n1000 (9.00%)\nof 11000 (99.00%)" fontsize=14 shape=box tooltip="tee testdata/source2:2 (11000)" color="#b20000" fillcolor="#edd5d5"]
-N4 [label="tee\nsource2:8\n100 (0.9%)" fontsize=10 shape=box tooltip="tee testdata/source2:8 (100)" color="#b2b0aa" fillcolor="#edecec"]
-N5 [label="bar\nsource1:10\n10 (0.09%)" fontsize=9 shape=box tooltip="bar testdata/source1:10 (10)" color="#b2b2b1" fillcolor="#ededed"]
-N6 [label="bar\nsource1:10\n0 of 100 (0.9%)" fontsize=8 shape=box tooltip="bar testdata/source1:10 (100)" color="#b2b0aa" fillcolor="#edecec"]
-N7 [label="foo\nsource1:4\n0 of 10 (0.09%)" fontsize=8 shape=box tooltip="foo testdata/source1:4 (10)" color="#b2b2b1" fillcolor="#ededed"]
+N1 [label="tee\nsource2:8\n10000 (90.00%)" id="node1" fontsize=24 shape=box tooltip="tee testdata/source2:8 (10000)" color="#b20500" fillcolor="#edd6d5"]
+N2 [label="main\nsource1:2\n1 (0.009%)\nof 11111 (100%)" id="node2" fontsize=9 shape=box tooltip="main testdata/source1:2 (11111)" color="#b20000" fillcolor="#edd5d5"]
+N3 [label="tee\nsource2:2\n1000 (9.00%)\nof 11000 (99.00%)" id="node3" fontsize=14 shape=box tooltip="tee testdata/source2:2 (11000)" color="#b20000" fillcolor="#edd5d5"]
+N4 [label="tee\nsource2:8\n100 (0.9%)" id="node4" fontsize=10 shape=box tooltip="tee testdata/source2:8 (100)" color="#b2b0aa" fillcolor="#edecec"]
+N5 [label="bar\nsource1:10\n10 (0.09%)" id="node5" fontsize=9 shape=box tooltip="bar testdata/source1:10 (10)" color="#b2b2b1" fillcolor="#ededed"]
+N6 [label="bar\nsource1:10\n0 of 100 (0.9%)" id="node6" fontsize=8 shape=box tooltip="bar testdata/source1:10 (100)" color="#b2b0aa" fillcolor="#edecec"]
+N7 [label="foo\nsource1:4\n0 of 10 (0.09%)" id="node7" fontsize=8 shape=box tooltip="foo testdata/source1:4 (10)" color="#b2b2b1" fillcolor="#ededed"]
 N2 -> N3 [label=" 11000" weight=100 penwidth=5 color="#b20000" tooltip="main testdata/source1:2 -> tee testdata/source2:2 (11000)" labeltooltip="main testdata/source1:2 -> tee testdata/source2:2 (11000)"]
 N3 -> N1 [label=" 10000" weight=91 penwidth=5 color="#b20500" tooltip="tee testdata/source2:2 -> tee testdata/source2:8 (10000)" labeltooltip="tee testdata/source2:2 -> tee testdata/source2:8 (10000)"]
 N6 -> N4 [label=" 100" color="#b2b0aa" tooltip="bar testdata/source1:10 -> tee testdata/source2:8 (100)" labeltooltip="bar testdata/source1:10 -> tee testdata/source2:8 (100)"]