Merge pull request #53 from atc0005/i52-add-support-for-contexts

Implement context support in teams subpkg, app

cmd/send2teams/main.go

@@ -8,6 +8,7 @@
 package main
 
 import (
+	"context"
 	"errors"
 	"flag"
 	"log"
@@ -79,9 +80,12 @@ func main() {
 		os.Exit(1)
 	}
 
+	ctxSubmissionTimeout, cancel := context.WithTimeout(context.Background(), config.TeamsSubmissionTimeout)
+	defer cancel()
+
 	// Submit message card, retry submission if needed up to specified number
-	// of retry attempts.
-	if err := teams.SendMessage(cfg.WebhookURL, msgCard, cfg.Retries, cfg.RetriesDelay); err != nil {
+	// of retry attempts or until context expires.
+	if err := teams.SendMessage(ctxSubmissionTimeout, cfg.WebhookURL, msgCard, cfg.Retries, cfg.RetriesDelay); err != nil {
 
 		// Display error output if silence is not requested
 		if !cfg.SilentOutput {

go.mod

@@ -7,12 +7,18 @@
 
 module github.com/atc0005/send2teams
 
+// replace github.com/atc0005/go-teams-notify => ../go-teams-notify
+
 require (
 	//gopkg.in/dasrick/go-teams-notify.v1 v1.2.0
 
 	// temporarily use our fork while developing changes for potential
 	// inclusion in the upstream project
-	github.com/atc0005/go-teams-notify v1.3.1-0.20200418112621-bff30feb673e
+	//
+	// temporarily use local copy instead of pinning to a specific commit in
+	// our test branch
+	//github.com/atc0005/go-teams-notify v0.0.0
+	github.com/atc0005/go-teams-notify v1.3.1-0.20200419155834-55cca556e726
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	gopkg.in/yaml.v2 v2.2.8 // indirect
 )

go.sum

@@ -1,5 +1,5 @@
-github.com/atc0005/go-teams-notify v1.3.1-0.20200418112621-bff30feb673e h1:zRyZGkOWTLymKTp96PmPaOO1KIAtS0YBvAeTIKEodNs=
-github.com/atc0005/go-teams-notify v1.3.1-0.20200418112621-bff30feb673e/go.mod h1:zUADEXrhalWyaQvxzYgHswljBWycIpX1UAFrggjcdi4=
+github.com/atc0005/go-teams-notify v1.3.1-0.20200419155834-55cca556e726 h1:pUJFxj7XRR6UxgWTvG4BCf1cVsn7nNqxdigBhMd1r/c=
+github.com/atc0005/go-teams-notify v1.3.1-0.20200419155834-55cca556e726/go.mod h1:zUADEXrhalWyaQvxzYgHswljBWycIpX1UAFrggjcdi4=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=

internal/config/config.go

@@ -12,8 +12,11 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"time"
 
 	"github.com/atc0005/send2teams/teams"
+	// temporarily use our fork while developing changes for potential
+	// inclusion in the upstream project
 )
 
 const (
@@ -54,6 +57,11 @@ var version string = "dev build"
 const myAppName string = "send2teams"
 const myAppURL string = "https://github.com/atc0005/" + myAppName
 
+// TeamsSubmissionTimeout is the timeout value for sending messages to
+// Microsoft Teams. This value is used to build a context with the desired
+// timeout value.
+const TeamsSubmissionTimeout time.Duration = 5 * time.Second
+
 // Config is a unified set of configuration values for this application. This
 // struct is configured via command-line flags provided by the user.
 type Config struct {

teams/teams.go

@@ -9,6 +9,7 @@ package teams
 
 import (
 	"bytes"
+	"context"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -272,7 +273,9 @@ func ConvertEOLToBreak(s string) string {
 // SendMessage is a wrapper function for setting up and using the
 // goteamsnotify client to send a message card to Microsoft Teams via a
 // webhook URL.
-func SendMessage(webhookURL string, message goteamsnotify.MessageCard, retries int, retriesDelay int) error {
+func SendMessage(ctx context.Context, webhookURL string, message goteamsnotify.MessageCard, retries int, retriesDelay int) error {
+
+	// NOTE: The caller is responsible for setting the desired context timeout
 
 	// init the client
 	mstClient := goteamsnotify.NewClient()
@@ -286,16 +289,57 @@ func SendMessage(webhookURL string, message goteamsnotify.MessageCard, retries i
 	// times before giving up
 	for attempt := 1; attempt <= attemptsAllowed; attempt++ {
 
+		// While the context is passed to mstClient.SendWithContext and it
+		// should ensure that it is respected, we check here at the start of
+		// the loop iteration (either first or subsequent) in order to return
+		// early in an effort to prevent undesired message attempts
+		if ctx.Err() != nil {
+			msg := fmt.Sprintf(
+				"SendMessage: context cancelled or expired: %v; aborting message submission after %d of %d attempts",
+				ctx.Err().Error(),
+				attempt,
+				attemptsAllowed,
+			)
+
+			// if this is set, we're looking at the second (incomplete)
+			// iteration
+			if result != nil {
+				msg += ": " + result.Error()
+			}
+
+			logger.Println(msg)
+			return fmt.Errorf(msg)
+		}
+
 		// the result from the last attempt is returned to the caller
-		result = mstClient.Send(webhookURL, message)
+		result = mstClient.SendWithContext(ctx, webhookURL, message)
 		if result != nil {
-			logger.Printf("SendMessage: Attempt %d of %d to send messaged failed: %v",
+
+			// check context again?
+			if ctx.Err() != nil {
+				errMsg := fmt.Errorf(
+					"SendMessage: Attempt %d of %d to send message failed: %v",
+					attempt,
+					attemptsAllowed,
+					result,
+				)
+				logger.Println(errMsg.Error())
+
+				return errMsg
+			}
+
+			// logger.Printf("Type of err: %T\n", result)
+			logger.Printf("SendMessage: Attempt %d of %d to send message failed: %v\n",
 				attempt, attemptsAllowed, result)
 			time.Sleep(time.Duration(retriesDelay) * time.Second)
 			continue
 		}
 
-		logger.Println("SendMessage: successfully sent message")
+		logger.Printf(
+			"SendMessage: successfully sent message after %d of %d attempts\n",
+			attempt,
+			attemptsAllowed,
+		)
 		break
 	}
 

vendor/modules.txt

@@ -1,2 +1,2 @@
-# github.com/atc0005/go-teams-notify v1.3.1-0.20200418112621-bff30feb673e
+# github.com/atc0005/go-teams-notify v1.3.1-0.20200419155834-55cca556e726
 github.com/atc0005/go-teams-notify