m/pkg/logtree: implement concise stringification
This adds a new method on LogEntry: ConciseString(). It's designed to
be used in cases where we want to display the log line on some
limited-width (and likely non-interactive) log console, like TTY
consoles in Metropolis.
This is a bit too Metropolis-specific to my liking (we hardcode some
logic related to the layout of root.role.*), but it'll do for now.
Change-Id: I1079b8b19a3c304fcc5077ce6b4c69887a34d7ae
Reviewed-on: https://review.monogon.dev/c/monogon/+/1359
Reviewed-by: Leopold Schabel <leo@monogon.tech>
Tested-by: Jenkins CI
diff --git a/go.mod b/go.mod
index 9ec5608..a69c12c 100644
--- a/go.mod
+++ b/go.mod
@@ -100,6 +100,7 @@
github.com/mdlayher/genetlink v1.2.0
github.com/mdlayher/netlink v1.6.0
github.com/mdlayher/raw v0.1.0
+ github.com/mitchellh/go-wordwrap v1.0.0
github.com/opencontainers/runc v1.1.3
github.com/packethost/packngo v0.29.0
github.com/pierrec/lz4/v4 v4.1.14
@@ -290,7 +291,6 @@
github.com/mindprince/gonvml v0.0.0-20190828220739-9ebdce4bb989 // indirect
github.com/mistifyio/go-zfs v2.1.2-0.20190413222219-f784269be439+incompatible // indirect
github.com/mitchellh/go-homedir v1.1.0 // indirect
- github.com/mitchellh/go-wordwrap v1.0.0 // indirect
github.com/mitchellh/mapstructure v1.4.2 // indirect
github.com/moby/locker v1.0.1 // indirect
github.com/moby/spdystream v0.2.0 // indirect
diff --git a/metropolis/pkg/logtree/BUILD.bazel b/metropolis/pkg/logtree/BUILD.bazel
index aabc40d..5c4237c 100644
--- a/metropolis/pkg/logtree/BUILD.bazel
+++ b/metropolis/pkg/logtree/BUILD.bazel
@@ -21,6 +21,7 @@
deps = [
"//metropolis/pkg/logbuffer",
"//metropolis/proto/api",
+ "@com_github_mitchellh_go_wordwrap//:go-wordwrap",
"@org_golang_google_protobuf//types/known/timestamppb",
],
)
diff --git a/metropolis/pkg/logtree/journal.go b/metropolis/pkg/logtree/journal.go
index d29fdaa..5df6e1a 100644
--- a/metropolis/pkg/logtree/journal.go
+++ b/metropolis/pkg/logtree/journal.go
@@ -59,21 +59,25 @@
// represented by heads[DN]/tails[DN] pointers in journal and nextLocal/prevLocal
// pointers in entries:
//
-// .------------. .------------. .------------.
-// | dn: A.B | | dn: Z | | dn: A.B |
-// | time: 1 | | time: 2 | | time: 3 |
-// |------------| |------------| |------------|
-// | nextGlobal :------->| nextGlobal :------->| nextGlobal :--> nil
+// .------------. .------------. .------------.
+// | dn: A.B | | dn: Z | | dn: A.B |
+// | time: 1 | | time: 2 | | time: 3 |
+// |------------| |------------| |------------|
+// | nextGlobal :------->| nextGlobal :------->| nextGlobal :--> nil
+//
// nil <-: prevGlobal |<-------: prevGlobal |<-------| prevGlobal |
-// |------------| |------------| n |------------|
-// | nextLocal :---. n | nextLocal :->i .-->| nextLocal :--> nil
+//
+// |------------| |------------| n |------------|
+// | nextLocal :---. n | nextLocal :->i .-->| nextLocal :--> nil
+//
// nil <-: prevLocal |<--: i<-: prevLocal | l :---| prevLocal |
-// '------------' | l '------------' | '------------'
-// ^ '----------------------' ^
-// | ^ |
-// | | |
-// ( head ) ( tails[Z] ) ( tail )
-// ( heads[A.B] ) ( heads[Z] ) ( tails[A.B] )
+//
+// '------------' | l '------------' | '------------'
+// ^ '----------------------' ^
+// | ^ |
+// | | |
+// ( head ) ( tails[Z] ) ( tail )
+// ( heads[A.B] ) ( heads[Z] ) ( tails[A.B] )
type journal struct {
// mu locks the rest of the structure. It must be taken during any operation on the
// journal.
@@ -232,3 +236,70 @@
}
}
+
+// Shorten returns a shortened version of this DN for constrained logging
+// environments like tty0 logging.
+//
+// If ShortenDictionary is given, it will be used to replace DN parts with
+// shorter equivalents. For example, with the dictionary:
+//
+// { "foobar": "foo", "manager": "mgr" }
+//
+// The DN some.foobar.logger will be turned into some.foo.logger before further
+// being processed by the shortening mechanism.
+//
+// The shortening rules applied are Metropolis-specific.
+func (d DN) Shorten(dict ShortenDictionary, maxLen int) string {
+ path, _ := d.Path()
+ // Apply DN part shortening rules.
+ if dict != nil {
+ for i, p := range path {
+ if sh, ok := dict[p]; ok {
+ path[i] = sh
+ }
+ }
+ }
+
+ // This generally shouldn't happen.
+ if len(path) == 0 {
+ return "?"
+ }
+
+ // Strip 'root.' prefix.
+ if len(path) > 1 && path[0] == "root" {
+ path = path[1:]
+ }
+
+ // Replace role.xxx.yyy.zzz with xxx.zzz - stripping everything between the role
+ // name and the last element of the path.
+ if path[0] == "role" && len(path) > 1 {
+ if len(path) == 2 {
+ path = path[1:]
+ } else {
+ path = []string{
+ path[1],
+ path[len(path)-1],
+ }
+ }
+ }
+
+ // Join back to be ' '-delimited, and ellipsize if too long.
+ s := strings.Join(path, " ")
+ if overflow := len(s) - maxLen; overflow > 0 {
+ s = "..." + s[overflow+3:]
+ }
+ return s
+}
+
+type ShortenDictionary map[string]string
+
+var MetropolisShortenDict = ShortenDictionary{
+ "controlplane": "cplane",
+ "map-cluster-membership": "map-membership",
+ "cluster-membership": "cluster",
+ "controller-manager": "controllers",
+ "networking": "net",
+ "network": "net",
+ "interfaces": "ifaces",
+ "kubernetes": "k8s",
+}
diff --git a/metropolis/pkg/logtree/journal_test.go b/metropolis/pkg/logtree/journal_test.go
index 474748a..1df3f12 100644
--- a/metropolis/pkg/logtree/journal_test.go
+++ b/metropolis/pkg/logtree/journal_test.go
@@ -146,3 +146,28 @@
t.Fatalf("Subtree(a.b): %s", res)
}
}
+
+func TestDN_Shorten(t *testing.T) {
+ for i, te := range []struct {
+ input string
+ maxLen int
+ want string
+ }{
+ {"root.role.controlplane.launcher.consensus.autopromoter", 20, "cplane autopromoter"},
+ {"networking.interfaces", 20, "net ifaces"},
+ {"hostsfile", 20, "hostsfile"},
+ {"root.dhcp-server", 20, "dhcp-server"},
+ {"root.role.kubernetes.run.kubernetes.apiserver", 20, "k8s apiserver"},
+ {"some.very.long.dn.that.cant.be.shortened", 20, "...cant be shortened"},
+ {"network.interfaces.dhcp", 20, "net ifaces dhcp"},
+ } {
+ got := DN(te.input).Shorten(MetropolisShortenDict, te.maxLen)
+ if len(got) > te.maxLen {
+ t.Errorf("case %d: output %q too long, got %d bytes, wanted %d", i, got, len(got), te.maxLen)
+ } else {
+ if te.want != got {
+ t.Errorf("case %d: wanted %q, got %q", i, te.want, got)
+ }
+ }
+ }
+}
diff --git a/metropolis/pkg/logtree/logtree_entry.go b/metropolis/pkg/logtree/logtree_entry.go
index 442d456..a020910 100644
--- a/metropolis/pkg/logtree/logtree_entry.go
+++ b/metropolis/pkg/logtree/logtree_entry.go
@@ -20,6 +20,8 @@
"fmt"
"strings"
+ "github.com/mitchellh/go-wordwrap"
+
"source.monogon.dev/metropolis/pkg/logbuffer"
apb "source.monogon.dev/metropolis/proto/api"
)
@@ -57,6 +59,116 @@
return "INVALID"
}
+// ConciseString returns a concise representation of this log entry for
+// constrained environments, like TTY consoles.
+//
+// The output format is as follows:
+//
+// shortened dn I Hello there
+// some component W Something went wrong
+// shortened dn I Goodbye there
+// external stuff R I am en external process using raw logging.
+//
+// The above output is the result of calling ConciseString on three different
+// LogEntries.
+//
+// If maxWidth is greater than zero, word wrapping will be applied. For example,
+// with maxWidth set to 40:
+//
+// shortened I Hello there
+// some component W Something went wrong and here are the very long details that
+// | describe this particular issue: according to all known laws of
+// | aviation, there is no way a bee should be able to fly.
+// shortened dn I Goodbye there
+// external stuff R I am en external process using raw logging.
+//
+// The above output is also the result of calling ConciseString on three
+// different LogEntries.
+//
+// Multi-line log entries will emit 'continuation' lines (with '|') in the same
+// way as word wrapping does. That means that even with word wrapping disabled,
+// the result of this function might be multiline.
+//
+// The width of the first column (the 'shortened DN' column) is automatically
+// selected based on maxWidth. If maxWidth is less than 60, the column will be
+// omitted. For example, with maxWidth set to 20:
+//
+// I Hello there
+// W Something went wrong and here are the very long details that
+// | describe this particular issue: according to all known laws of
+// | aviation, there is no way a bee should be able to fly.
+// I Goodbye there
+// R I am en external process using raw logging.
+//
+// The given `dict` implements simple replacement rules for shortening the DN
+// parts of a log entry's DN. Some rules are hardcoded for Metropolis' DN tree.
+// If no extra shortening rules should be applied, dict can be set to ni// The
+// given `dict` implements simple replacement rules for shortening the DN parts
+// of a log entry's DN. Some rules are hardcoded for Metropolis' DN tree. If no
+// extra shortening rules should be applied, dict can be set to nil.
+func (l *LogEntry) ConciseString(dict ShortenDictionary, maxWidth int) string {
+ // Decide on a dnWidth.
+ dnWidth := 0
+ switch {
+ case maxWidth >= 80:
+ dnWidth = 20
+ case maxWidth >= 60:
+ dnWidth = 16
+ case maxWidth <= 0:
+ // No word wrapping.
+ dnWidth = 20
+ }
+
+ // Compute shortened DN, if needed.
+ sh := ""
+ if dnWidth > 0 {
+ sh = l.DN.Shorten(dict, dnWidth)
+ sh = fmt.Sprintf("%*s ", dnWidth, sh)
+ }
+
+ // Prefix of the first line emitted.
+ var prefix string
+ switch {
+ case l.Leveled != nil:
+ prefix = sh + string(l.Leveled.Severity()) + " "
+ case l.Raw != nil:
+ prefix = sh + "R "
+ }
+ // Prefix of rest of lines emitted.
+ continuationPrefix := strings.Repeat(" ", len(sh)) + "| "
+
+ // Collect lines based on the type of LogEntry.
+ var lines []string
+ collect := func(message string) {
+ if maxWidth > 0 {
+ message = wordwrap.WrapString(message, uint(maxWidth-len(prefix)))
+ }
+ for _, m2 := range strings.Split(message, "\n") {
+ if len(m2) == 0 {
+ continue
+ }
+ if len(lines) == 0 {
+ lines = append(lines, prefix+m2)
+ } else {
+ lines = append(lines, continuationPrefix+m2)
+ }
+ }
+ }
+ switch {
+ case l.Leveled != nil:
+ _, messages := l.Leveled.Strings()
+ for _, m := range messages {
+ collect(m)
+ }
+ case l.Raw != nil:
+ collect(l.Raw.String())
+ default:
+ return ""
+ }
+
+ return strings.Join(lines, "\n")
+}
+
// Strings returns the canonical representation of this payload split into a
// prefix and all lines that were contained in the original message. This is
// meant to be displayed to the user by showing the prefix before each line,
diff --git a/metropolis/pkg/logtree/logtree_test.go b/metropolis/pkg/logtree/logtree_test.go
index 315dbc3..a7614a4 100644
--- a/metropolis/pkg/logtree/logtree_test.go
+++ b/metropolis/pkg/logtree/logtree_test.go
@@ -237,3 +237,90 @@
t.Errorf("first entry at %d, second at %d, wanted one after the other", first, second)
}
}
+
+func TestLogEntry_ConciseString(t *testing.T) {
+ trim := func(s string) string {
+ return strings.Trim(s, "\n")
+ }
+ for i, te := range []struct {
+ entry *LogEntry
+ maxWidth int
+ want string
+ }{
+ {
+ &LogEntry{
+ Leveled: &LeveledPayload{
+ messages: []string{"Hello there!"},
+ severity: WARNING,
+ },
+ DN: "root.role.kubernetes.run.kubernetes.apiserver",
+ },
+ 120,
+ " k8s apiserver W Hello there!",
+ },
+ {
+ &LogEntry{
+ Leveled: &LeveledPayload{
+ messages: []string{"Hello there!", "I am multiline."},
+ severity: WARNING,
+ },
+ DN: "root.role.kubernetes.run.kubernetes.apiserver",
+ },
+ 120,
+ trim(`
+ k8s apiserver W Hello there!
+ | I am multiline.
+`),
+ },
+ {
+ &LogEntry{
+ Leveled: &LeveledPayload{
+ messages: []string{"Hello there! I am a very long string, and I will get wrapped to 120 columns because that's just how life is for long strings."},
+ severity: WARNING,
+ },
+ DN: "root.role.kubernetes.run.kubernetes.apiserver",
+ },
+ 120,
+ trim(`
+ k8s apiserver W Hello there! I am a very long string, and I will get wrapped to 120 columns because that's just
+ | how life is for long strings.
+`),
+ },
+ {
+ &LogEntry{
+ Leveled: &LeveledPayload{
+ messages: []string{"Hello there!"},
+ severity: WARNING,
+ },
+ DN: "root.role.kubernetes.run.kubernetes.apiserver",
+ },
+ 60,
+ trim(`
+ k8s apiserver W Hello there!
+`),
+ },
+ {
+ &LogEntry{
+ Leveled: &LeveledPayload{
+ messages: []string{"Hello there!"},
+ severity: WARNING,
+ },
+ DN: "root.role.kubernetes.run.kubernetes.apiserver",
+ },
+ 40,
+ "W Hello there!",
+ },
+ } {
+ got := te.entry.ConciseString(MetropolisShortenDict, te.maxWidth)
+ for _, line := range strings.Split(got, "\n") {
+ if want, got := te.maxWidth, len(line); got > want {
+ t.Errorf("Case %d, line %q too long (%d bytes, wanted at most %d)", i, line, got, want)
+ }
+ }
+ if te.want != got {
+ t.Errorf("Case %d, message diff", i)
+ t.Logf("Wanted:\n%s", te.want)
+ t.Logf("Got:\n%s", got)
+ }
+ }
+}