From e8325711b39f2f685c557652aae8e45666ee746e Mon Sep 17 00:00:00 2001
From: Keepers <ryanfkeepers@gmail.com>
Date: Thu, 25 May 2023 00:28:40 -0600
Subject: [PATCH] update logging standards doc (#3497)

#### Type of change

- [x] :world_map: Documentation
---
 src/pkg/logger/example_logger_test.go | 46 +++++++++++++++++++++------
 1 file changed, 36 insertions(+), 10 deletions(-)

diff --git a/src/pkg/logger/example_logger_test.go b/src/pkg/logger/example_logger_test.go
index b71cddf11..b141efecf 100644
--- a/src/pkg/logger/example_logger_test.go
+++ b/src/pkg/logger/example_logger_test.go
@@ -6,6 +6,7 @@ import (
 	"github.com/alcionai/clues"
 
 	"github.com/alcionai/corso/src/internal/connector"
+	"github.com/alcionai/corso/src/internal/connector/graph"
 	"github.com/alcionai/corso/src/pkg/logger"
 	"github.com/alcionai/corso/src/pkg/path"
 )
@@ -62,7 +63,8 @@ func Example_seed() {
 func Example_logger_standards() {
 	log := logger.Ctx(context.Background())
 
-	// 1. Keep messages short.  Lowercase text, no ending punctuation.
+	// 1. Keep messages short. When possible, messages should state the current action.
+	// Lowercase text, no ending punctuation.
 	// This ensures logs are easy to scan, and simple to grok.
 	//
 	// preferred
@@ -70,7 +72,15 @@ func Example_logger_standards() {
 	// avoid
 	log.Info("Getting one item from the service so that we can send it through the item feed.")
 
-	// 2. Do not fmt values into the message.  Use With() or -w() to add structured data.
+	// 2. Avoid statements like "unable to...", "failed to..", or "error when...".
+	// Error level logs automatically imply a failure to do the action.
+	//
+	// preferred
+	log.With("err", err).Error("connecting to repo")
+	// avoid
+	log.With("err", err).Error("unable to connect to repo")
+
+	// 3. Do not fmt values into the message.  Use With() or -w() to add structured data.
 	// By keeping dynamic data in a structured format, we maximize log readability,
 	// and make logs very easy to search or filter in bulk, and very easy to control pii.
 	//
@@ -80,7 +90,7 @@ func Example_logger_standards() {
 	// avoid
 	log.Errorf("getting item %s: %v", itemID, err)
 
-	// 3. Give data keys reasonable namespaces.  Use snake_case.
+	// 4. Give data keys reasonable namespaces.  Use snake_case.
 	// Overly generic keys can collide unexpectedly.
 	//
 	// preferred
@@ -98,14 +108,14 @@ func Example_logger_standards() {
 	// avoid
 	log.With("err", err).Warn("getting item")
 
-	// 4. Avoid Panic/Fatal-level logging.  Prefer Error.
+	// 5. Avoid Panic/Fatal-level logging.  Prefer Error.
 	// Panic and Fatal logging can crash the application without
 	// flushing buffered logs and finishing out other telemetry.
 	//
 	// preferred
-	log.With("err", err).Error("unable to connect")
+	log.With("err", err).Error("connecting to repo")
 	// avoid
-	log.With("err", err).Panic("unable to connecct")
+	log.With("err", err).Panic("connecting to repo")
 }
 
 // ExampleLoggerCluesStandards reviews code standards around using the Clues package while logging.
@@ -124,7 +134,14 @@ func Example_logger_clues_standards() {
 	ctx = clues.Add(ctx, "item_id", itemID)
 	logger.Ctx(ctx).With(clues.In(ctx).Slice()...).Info("getting item")
 
-	// 2. Always extract structured data from errors.
+	// 2. The last func to handle a context must add the clues to the error.
+	//
+	// preferred
+	err := clues.Wrap(err, "reason").WithClues(ctx)
+	// this dereference added for linter happiness
+	_ = err
+
+	// 3. Always extract structured data from errors.
 	//
 	// preferred
 	log.With("error", err).Errorw("getting item", clues.InErr(err).Slice()...)
@@ -153,7 +170,15 @@ func Example_logger_clues_standards() {
 	// Ex: clues.Hide(userName).  This will hash the value according to
 	// the user's hash algorithm configuration.
 	//
-	// Third: structs that comply with clues.Concealer.  The Concealer
+	// Third: managed string concealers.  Certain values have common
+	// format and content, but appear commonly in the code as strings.
+	// Examples include URLs and kopia repository paths.  These values
+	// may have a concealer built specifically for them to maximize the
+	// data we can view when debugging, instead of hashing the complete
+	// string.  See graph/middleware.go LoggableURL{} and path/elements.go
+	// LoggableDir{}.
+	//
+	// Fourth: structs that comply with clues.Concealer.  The Concealer
 	// interface requires a struct to comply with Conceal() (for cases
 	// where the struct is handed to a clues aggregator directly), and
 	// fmt's Format(state, verb), where the assumption is the standard
@@ -166,7 +191,8 @@ func Example_logger_clues_standards() {
 		"resource_type", connector.Users,
 		// string containing sensitive info, wrap with Hide()
 		"user_name", clues.Hide("your_user_name@microsoft.example"),
+		// string partially concealed by a managed concealer.
+		"request_url", graph.LoggableURL("https://corsobackup.io"),
 		// a concealer-compliant struct, safe to add plainly
-		"storage_path", itemPath,
-	)
+		"storage_path", itemPath)
 }