CLI: Allow snapshot inspect to work on internal raft snapshots directly. (#10089)

* CLI: Add support for reading internal raft snapshots to snapshot inspect

* Add snapshot inspect test for raw state files

* Add changelog entry

* Update .changelog/10089.txt

.changelog/10089.txt

@@ -0,0 +1,4 @@
+```release-note:improvement
+cli: snapshot inspect command can now inspect raw snapshots from a server's data
+dir.
+```

command/snapshot/inspect/snapshot_inspect.go

@@ -1,10 +1,13 @@
 package inspect
 
 import (
+	"encoding/json"
 	"flag"
 	"fmt"
 	"io"
+	"io/ioutil"
 	"os"
+	"path"
 	"sort"
 	"strings"
 
@@ -111,7 +114,29 @@ func (c *cmd) Run(args []string) int {
 	}
 	defer f.Close()
 
-	readFile, meta, err := snapshot.Read(hclog.New(nil), f)
+	var readFile *os.File
+	var meta *raft.SnapshotMeta
+
+	if strings.ToLower(path.Base(file)) == "state.bin" {
+		// This is an internal raw raft snapshot not a gzipped archive one
+		// downloaded from the API, we can read it directly
+		readFile = f
+
+		// Assume the meta is colocated and error if not.
+		metaRaw, err := ioutil.ReadFile(path.Join(path.Dir(file), "meta.json"))
+		if err != nil {
+			c.UI.Error(fmt.Sprintf("Error reading meta.json from internal snapshot dir: %s", err))
+			return 1
+		}
+		var metaDecoded raft.SnapshotMeta
+		err = json.Unmarshal(metaRaw, &metaDecoded)
+		if err != nil {
+			c.UI.Error(fmt.Sprintf("Error parsing meta.json from internal snapshot dir: %s", err))
+			return 1
+		}
+		meta = &metaDecoded
+	} else {
+		readFile, meta, err = snapshot.Read(hclog.New(nil), f)
 		if err != nil {
 			c.UI.Error(fmt.Sprintf("Error reading snapshot: %s", err))
 		}
@@ -123,6 +148,7 @@ func (c *cmd) Run(args []string) int {
 				c.UI.Error(fmt.Sprintf("Failed to clean up temp snapshot: %v", err))
 			}
 		}()
+	}
 
 	info, err := c.enhance(readFile)
 	if err != nil {

command/snapshot/inspect/snapshot_inspect_test.go

@@ -149,3 +149,23 @@ func TestSnapshotInspectKVDetailsDepthFilterCommand(t *testing.T) {
 	want := golden(t, t.Name(), ui.OutputWriter.String())
 	require.Equal(t, want, ui.OutputWriter.String())
 }
+
+// TestSnapshotInspectCommandRaw test reading a snaphost directly from a raft
+// data dir.
+func TestSnapshotInspectCommandRaw(t *testing.T) {
+
+	filepath := "./testdata/raw/state.bin"
+
+	// Inspect the snapshot
+	ui := cli.NewMockUi()
+	c := New(ui)
+	args := []string{filepath}
+
+	code := c.Run(args)
+	if code != 0 {
+		t.Fatalf("bad: %d. %#v", code, ui.ErrorWriter.String())
+	}
+
+	want := golden(t, t.Name(), ui.OutputWriter.String())
+	require.Equal(t, want, ui.OutputWriter.String())
+}

command/snapshot/inspect/testdata/TestSnapshotInspectCommandRaw.golden

@@ -0,0 +1,19 @@
+ ID           2-13-1602222343947
+ Size         5141
+ Index        13
+ Term         2
+ Version      1
+
+ Type                        Count      Size
+ ----                        ----       ----
+ Register                    3          1.7KB
+ ConnectCA                   1          1.2KB
+ ConnectCAProviderState      1          1.1KB
+ Index                       12         344B
+ Autopilot                   1          199B
+ ConnectCAConfig             1          197B
+ FederationState             1          139B
+ SystemMetadata              1          68B
+ ChunkingState               1          12B
+ ----                        ----       ----
+ Total                                  5KB

command/snapshot/inspect/testdata/raw/meta.json

@@ -0,0 +1 @@
+{"Version":1,"ID":"2-13-1602222343947","Index":13,"Term":2,"Peers":"ka4xMjcuMC4wLjE6ODMwMA==","Configuration":{"Servers":[{"Suffrage":0,"ID":"a577b288-b354-770e-e909-da0972eb20e8","Address":"127.0.0.1:8300"}]},"ConfigurationIndex":1,"Size":5141}

website/content/commands/snapshot/inspect.mdx

@@ -12,6 +12,15 @@ snapshot of the state of the Consul servers which includes key/value entries,
 service catalog, prepared queries, sessions, and ACLs. The snapshot is read
 from the given file.
 
+-> Typically this is used with Consul self-contained Snapshot files obtained
+using the [`consul snapshot`](/commands/snapshot) command or [Snapshot
+API](/api-docs/snapshot#generate-snapshot). If the file provided is named
+`state.bin` however, the command will assume it is a raw raft snapshot in a
+Consul server data directory and will attempt to read it directly. The
+`state.bin` file must still be in the same directory as it's associated
+`meta.json` file. This is useful for debugging data on live servers without
+making a complete new snapshot via the CLI or API first.
+
 The following fields are displayed when inspecting a snapshot:
 
 - `ID` - A unique ID for the snapshot, only used for differentiation purposes.
@@ -106,6 +115,29 @@ $ consul snapshot inspect -kvdetails -kvdepth 3 -kvfilter vault/core backup.snap
 Please see the [HTTP API](/api/snapshot) documentation for
 more details about snapshot internals.
 
+To inspect an internal snapshot directly from a Consul server data directory:
+
+```shell-session
+$ consul snapshot inspect /opt/consul/raft/snapshots/9-4600669-1618935304715/state.bin
+ ID           9-4600669-1618935304715
+ Size         4625420898
+ Index        4600669
+ Term         9
+ Version      1
+
+ Type                       Count        Size
+ ----                       ----         ----
+ KVS                        4089785      4.3GB
+ Register                   9            5.2KB
+ CoordinateBatchUpdate      3            465B
+ Index                      8            224B
+ Autopilot                  1            199B
+ FederationState            1            139B
+ ChunkingState              1            12B
+ ----                       ----         ----
+ Total                                   4.3GB
+```
+
 #### Command Options
 
 - `-kvdetails` - Optional, provides a space usage breakdown for any KV data stored in Consul.