Add lsimap troubleshooting tool

.gitignore

@@ -39,6 +39,7 @@
 # Ignore binaries at root of repo (often generated here when testing)
 /check_imap_mailbox
 /list-emails
+/lsimap
 
 # Help prevent accidentally including this credentials file in the repo
 /accounts.ini

Makefile

@@ -31,7 +31,7 @@
 SHELL = /bin/bash
 
 # Space-separated list of cmd/BINARY_NAME directories to build
-WHAT 					= check_imap_mailbox list-emails
+WHAT 					= check_imap_mailbox list-emails lsimap
 
 # TODO: This will need to be standardized across all cmd files in order to
 # work as intended.

README.md

@@ -18,6 +18,7 @@ Various tools used to monitor mail services
 - [Features](#features)
   - [`check_imap_mailbox`](#check_imap_mailbox)
   - [`list-emails`](#list-emails)
+  - [`lsimap`](#lsimap)
 - [Requirements](#requirements)
   - [Building source code](#building-source-code)
   - [Running](#running)
@@ -32,13 +33,16 @@ Various tools used to monitor mail services
     - [Configuration file](#configuration-file)
       - [Settings](#settings)
       - [Usage](#usage)
+  - [`lsimap`](#lsimap-1)
+    - [Command-line arguments](#command-line-arguments-2)
 - [Examples](#examples)
   - [`check_imap_mailbox`](#check_imap_mailbox-2)
     - [As a Nagios plugin](#as-a-nagios-plugin)
     - [Login failure](#login-failure)
   - [`list-emails`](#list-emails-2)
     - [No options](#no-options)
     - [Alternate locations for config file, log and report directories](#alternate-locations-for-config-file-log-and-report-directories)
+  - [`lsimap`](#lsimap-2)
 - [License](#license)
 - [References](#references)
 
@@ -51,10 +55,11 @@ submit improvements for review and potential inclusion into the project.
 
 This repo contains various tools used to monitor mail services.
 
-| Tool Name            | Overall Status | Description                                                |
-| -------------------- | -------------- | ---------------------------------------------------------- |
-| `check_imap_mailbox` | Stable         | Nagios plugin used to monitor mailboxes for items          |
-| `list-emails`        | Stable         | Small CLI app used to generate listing of mailbox contents |
+| Tool Name            | Overall Status | Description                                                              |
+| -------------------- | -------------- | ------------------------------------------------------------------------ |
+| `check_imap_mailbox` | Stable         | Nagios plugin used to monitor mailboxes for items                        |
+| `list-emails`        | Stable         | Small CLI app used to generate listing of mailbox contents               |
+| `lsimap`             | Alpha          | Small CLI tool to list advertised capabilities for specified IMAP server |
 
 ## Features
 
@@ -102,6 +107,21 @@ This repo contains various tools used to monitor mail services.
     - the intent is to help prevent MySQL errors when posting summary reports
       - e.g., `ERROR 1366 (22007): Incorrect string value`
 
+### `lsimap`
+
+- Quick one-off tool to list advertised capabilities for specified IMAP server
+- Leveled logging
+  - `console writer`: human-friendly, colorized output
+  - choice of `disabled`, `panic`, `fatal`, `error`, `warn`, `info` (the
+    default), `debug` or `trace`
+  - enable `debug` level to monitor submitted IMAP commands and received IMAP
+    server responses
+- TLS IMAP4 connectivity
+  - port defaults to 993/tcp
+  - network type defaults to either of IPv4 and IPv6, but optionally limited
+    to IPv4-only or IPv6-only
+  - user-specified minimum TLS version
+
 ## Requirements
 
 The following is a loose guideline. Other combinations of Go and operating
@@ -288,6 +308,24 @@ You may also place the file wherever you like and refer to it using the
 `-config-file` (full-length flag name). See the [Examples](#examples) and
 [Command-line arguments](#command-line-arguments) sections for usage details.
 
+### `lsimap`
+
+#### Command-line arguments
+
+- Flags marked as **`required`** must be set via CLI flag.
+- Flags *not* marked as required are for settings where a useful default is
+  already defined.
+
+| Option          | Required | Default        | Repeat | Possible                                                                | Description                                                                                                                |
+| --------------- | -------- | -------------- | ------ | ----------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------- |
+| `h`, `help`     | No       |                | No     | `-h`, `--help`                                                          | Generate listing of all valid command-line options and applicable (short) guidance for using them.                         |
+| `server`        | Yes      | *empty string* | No     | *valid FQDN or IP Address*                                              | The fully-qualified domain name of the remote mail server.                                                                 |
+| `port`          | No       | `993`          | No     | *valid IMAP TCP port*                                                   | TCP port used to connect to the remote mail server. This is usually the same port used for TLS encrypted IMAP connections. |
+| `net-type`      | No       | `auto`         | No     | `auto`, `tcp4`, `tcp6`                                                  | Limits network connections to remote mail servers to one of the specified types.                                           |
+| `min-tls`       | No       | `tls12`        | No     | `tls10`, `tls11`, `tls12`, `tls13`                                      | Limits version of TLS used for connections to remote mail servers.                                                         |
+| `logging-level` | No       | `info`         | No     | `disabled`, `panic`, `fatal`, `error`, `warn`, `info`, `debug`, `trace` | Sets log level.                                                                                                            |
+| `version`       | No       | `false`        | No     | `true`, `false`                                                         | Whether to display application version and then immediately exit application                                               |
+
 ## Examples
 
 ### `check_imap_mailbox`
@@ -351,6 +389,54 @@ Checking account: email2
 OK: Successfully generated reports for accounts: [email protected], [email protected]
 ```
 
+### `lsimap`
+
+Quick listings for outlook.office365.com and imap.gmail.com.
+
+This tool can be useful for determining at a glance what authentication
+mechanisms are supported by an IMAP server.
+
+```console
+$ ./lsimap --server outlook.office365.com
+6:10AM INF cmd\lsimap\main.go:61 > Connection established to server
+6:10AM INF cmd\lsimap\main.go:70 > Gathering pre-login capabilities
+6:10AM INF cmd\lsimap\main.go:87 > Capability: AUTH=PLAIN
+6:10AM INF cmd\lsimap\main.go:87 > Capability: AUTH=XOAUTH2
+6:10AM INF cmd\lsimap\main.go:87 > Capability: CHILDREN
+6:10AM INF cmd\lsimap\main.go:87 > Capability: ID
+6:10AM INF cmd\lsimap\main.go:87 > Capability: IDLE
+6:10AM INF cmd\lsimap\main.go:87 > Capability: IMAP4
+6:10AM INF cmd\lsimap\main.go:87 > Capability: IMAP4rev1
+6:10AM INF cmd\lsimap\main.go:87 > Capability: LITERAL+
+6:10AM INF cmd\lsimap\main.go:87 > Capability: MOVE
+6:10AM INF cmd\lsimap\main.go:87 > Capability: NAMESPACE
+6:10AM INF cmd\lsimap\main.go:87 > Capability: SASL-IR
+6:10AM INF cmd\lsimap\main.go:87 > Capability: UIDPLUS
+6:10AM INF cmd\lsimap\main.go:87 > Capability: UNSELECT
+6:10AM INF cmd\lsimap\main.go:95 > Connection to server closed
+
+$ ./lsimap --server imap.gmail.com
+6:10AM INF cmd\lsimap\main.go:61 > Connection established to server
+6:10AM INF cmd\lsimap\main.go:70 > Gathering pre-login capabilities
+6:10AM INF cmd\lsimap\main.go:87 > Capability: AUTH=OAUTHBEARER
+6:10AM INF cmd\lsimap\main.go:87 > Capability: AUTH=PLAIN
+6:10AM INF cmd\lsimap\main.go:87 > Capability: AUTH=PLAIN-CLIENTTOKEN
+6:10AM INF cmd\lsimap\main.go:87 > Capability: AUTH=XOAUTH
+6:10AM INF cmd\lsimap\main.go:87 > Capability: AUTH=XOAUTH2
+6:10AM INF cmd\lsimap\main.go:87 > Capability: CHILDREN
+6:10AM INF cmd\lsimap\main.go:87 > Capability: ID
+6:10AM INF cmd\lsimap\main.go:87 > Capability: IDLE
+6:10AM INF cmd\lsimap\main.go:87 > Capability: IMAP4rev1
+6:10AM INF cmd\lsimap\main.go:87 > Capability: NAMESPACE
+6:10AM INF cmd\lsimap\main.go:87 > Capability: QUOTA
+6:10AM INF cmd\lsimap\main.go:87 > Capability: SASL-IR
+6:10AM INF cmd\lsimap\main.go:87 > Capability: UNSELECT
+6:10AM INF cmd\lsimap\main.go:87 > Capability: X-GM-EXT-1
+6:10AM INF cmd\lsimap\main.go:87 > Capability: XLIST
+6:10AM INF cmd\lsimap\main.go:87 > Capability: XYZZY
+6:10AM INF cmd\lsimap\main.go:95 > Connection to server closed
+```
+
 ## License
 
 From the [LICENSE](LICENSE) file:

cmd/check_imap_mailbox/main.go

@@ -81,6 +81,7 @@ func main() {
 
 			return
 		}
+		logger.Debug().Msg("Connection established to server")
 
 		if loginErr := mbxs.Login(c, account.Username, account.Password, logger); loginErr != nil {
 			logger.Error().Err(loginErr).Msg("Login error occurred")

cmd/list-emails/main.go

@@ -100,6 +100,7 @@ func main() {
 
 			return
 		}
+		logger.Info().Msg("Connection established to server")
 
 		if loginErr := mbxs.Login(c, account.Username, account.Password, logger); loginErr != nil {
 			logger.Error().Err(loginErr).Msg("failed to login to server")

cmd/lsimap/doc.go

@@ -0,0 +1,18 @@
+// Copyright 2022 Adam Chalkley
+//
+// https://github.com/atc0005/check-mail
+//
+// Licensed under the MIT License. See LICENSE file in the project root for
+// full license information.
+
+// Small CLI tool to list advertised capabilities for specified IMAP server.
+//
+// See our [GitHub repo]:
+//
+//   - to review documentation (including examples)
+//   - for the latest code
+//   - to file an issue or submit improvements for review and potential
+//     inclusion into the project
+//
+// [GitHub repo]: https://github.com/atc0005/check-mail
+package main

cmd/lsimap/main.go

@@ -0,0 +1,98 @@
+// Copyright 2022 Adam Chalkley
+//
+// https://github.com/atc0005/check-mail
+//
+// Licensed under the MIT License. See LICENSE file in the project root for
+// full license information.
+
+//go:generate go-winres make --product-version=git-tag --file-version=git-tag
+
+package main
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"sort"
+
+	"github.com/atc0005/check-mail/internal/config"
+	"github.com/atc0005/check-mail/internal/mbxs"
+	"github.com/rs/zerolog"
+)
+
+func main() {
+
+	// Setup configuration by parsing user-provided flags
+	cfg, cfgErr := config.New(config.AppType{InspectorIMAPCaps: true})
+	switch {
+	case errors.Is(cfgErr, config.ErrVersionRequested):
+		fmt.Println(config.Version())
+
+		return
+
+	case cfgErr != nil:
+
+		// We make some assumptions when setting up our logger as we do not
+		// have a working configuration based on sysadmin-specified choices.
+		consoleWriter := zerolog.ConsoleWriter{Out: os.Stderr}
+		logger := zerolog.New(consoleWriter).With().Timestamp().Caller().Logger()
+
+		logger.Err(cfgErr).Msg("Error initializing application")
+
+		return
+	}
+
+	logger := cfg.Log.With().Logger()
+
+	// We're reusing the common "Accounts" field (and flags) in order to
+	// obtain specified server and port values vs adding standalone fields and
+	// flags; this is effectively a loop of 1 iteration (at least for now). At
+	// some point we may expand the scope of this tool to handle evaluating
+	// mail servers for a collection of accounts, so using a workflow intended
+	// for collections is probably appropriate.
+	for _, account := range cfg.Accounts {
+
+		// Open connection to IMAP server
+		c, err := mbxs.Connect(account.Server, account.Port, cfg.NetworkType, cfg.MinTLSVersion(), logger)
+		if err != nil {
+			logger.Error().Err(err).Msg("error connecting to server")
+			os.Exit(1)
+		}
+		logger.Info().Msg("Connection established to server")
+
+		// Enable client network command/response logging if global logging
+		// level indicates user wishes to see verbose details.
+		if zerolog.GlobalLevel() == zerolog.DebugLevel ||
+			zerolog.GlobalLevel() == zerolog.TraceLevel {
+			c.SetDebug(&logger)
+		}
+
+		logger.Info().Msg("Gathering pre-login capabilities")
+		capabilities, err := c.Capability()
+		if err != nil {
+			logger.Error().Err(err).Msg("Unable to list server capabilities")
+			os.Exit(1)
+		}
+
+		caps := make([]string, 0, len(capabilities))
+		for k, v := range capabilities {
+			if v {
+				caps = append(caps, k)
+			}
+		}
+
+		sort.Strings(caps)
+		// logger.Info().Msgf("Capabilities: %v", caps)
+		for _, capability := range caps {
+			logger.Info().Msgf("Capability: %v", capability)
+		}
+
+		logger.Debug().Msg("Closing connection to server")
+		if err := c.Logout(); err != nil {
+			logger.Error().Err(err).Msg("failed to close connection to server")
+			os.Exit(1)
+		}
+		logger.Info().Msg("Connection to server closed")
+
+	}
+}

cmd/lsimap/winres/winres.json

@@ -0,0 +1,53 @@
+{
+  "RT_MANIFEST": {
+    "#1": {
+      "0409": {
+        "identity": {
+          "name": "",
+          "version": ""
+        },
+        "description": "Small CLI tool to list advertised capabilities for specified IMAP server",
+        "minimum-os": "win7",
+        "execution-level": "as invoker",
+        "ui-access": false,
+        "auto-elevate": false,
+        "dpi-awareness": "system",
+        "disable-theming": false,
+        "disable-window-filtering": false,
+        "high-resolution-scrolling-aware": false,
+        "ultra-high-resolution-scrolling-aware": false,
+        "long-path-aware": false,
+        "printer-driver-isolation": false,
+        "gdi-scaling": false,
+        "segment-heap": false,
+        "use-common-controls-v6": false
+      }
+    }
+  },
+  "RT_VERSION": {
+    "#1": {
+      "0000": {
+        "fixed": {
+          "file_version": "0.0.0.0",
+          "product_version": "0.0.0.0"
+        },
+        "info": {
+          "0409": {
+            "Comments": "Part of the atc0005/check-mail project",
+            "CompanyName": "github.com/atc0005",
+            "FileDescription": "Small CLI tool to list advertised capabilities for specified IMAP server",
+            "FileVersion": "",
+            "InternalName": "lsimap",
+            "LegalCopyright": "© Adam Chalkley. Licensed under MIT.",
+            "LegalTrademarks": "",
+            "OriginalFilename": "main.go",
+            "PrivateBuild": "",
+            "ProductName": "check-mail",
+            "ProductVersion": "",
+            "SpecialBuild": ""
+          }
+        }
+      }
+    }
+  }
+}

internal/config/config.go

@@ -73,6 +73,15 @@ type AppType struct {
 	//
 	// Basic Authentication is used to login.
 	ReporterIMAPMailboxBasicAuth bool
+
+	// InspectorIMAPCaps represents an application used for one-off or
+	// isolated checks of an IMAP server's advertised capabilities.
+	//
+	// Unlike a monitoring plugin which is focused on specific attributes
+	// resulting in a severity-based outcome, an Inspector application is
+	// intended for examining a small set of targets for
+	// informational/troubleshooting purposes.
+	InspectorIMAPCaps bool
 }
 
 // MailAccount represents an email account listed within a configuration file.

internal/config/flags.go

@@ -24,14 +24,20 @@ func (c *Config) handleFlagsConfig(appType AppType) {
 	flag.StringVar(&c.NetworkType, "net-type", defaultNetworkType, networkTypeFlagHelp)
 	flag.StringVar(&c.minTLSVersion, "min-tls", defaultMinTLSVersion, minTLSVersionFlagHelp)
 
-	// currently only applies to list-emails app, don't expose to Nagios plugin
+	// Only applies to Reporter app
 	if appType.ReporterIMAPMailboxBasicAuth {
 		flag.StringVar(&c.ConfigFile, "config-file", defaultINIConfigFileName, iniConfigFileFlagHelp)
 		flag.StringVar(&c.ReportFileOutputDir, "report-file-dir", defaultReportFileOutputDir, reportFileOutputDirFlagHelp)
 		flag.StringVar(&c.LogFileOutputDir, "log-file-dir", defaultLogFileOutputDir, logFileOutputDirFlagHelp)
 	}
 
-	// currently only applies to Nagios plugin
+	// Inspector app
+	if appType.InspectorIMAPCaps {
+		flag.StringVar(&account.Server, "server", defaultServer, serverFlagHelp)
+		flag.IntVar(&account.Port, "port", defaultPort, portFlagHelp)
+	}
+
+	// Basic Auth Plugin
 	if appType.PluginIMAPMailboxBasicAuth {
 		flag.Var(&account.Folders, "folders", foldersFlagHelp)
 		flag.StringVar(&account.Username, "username", defaultUsername, usernameFlagHelp)