fix: remove duplicate logging

Errors are now wrapped and returned to the caller, rather than logged
and returned to the caller.

Propagating the error to the caller causes errors to logged by the
`main` function (if they're propagated that far). Logging them elsewhere
results in the error being logged more than once.

src/plugin/example.go

@@ -2,6 +2,7 @@ package plugin
 
 import (
 	"context"
+	"fmt"
 
 	"github.com/cultureamp/example-go-buildkite-plugin/buildkite"
 )
@@ -21,17 +22,15 @@ func (ep ExamplePlugin) Run(ctx context.Context, fetcher ConfigFetcher, agent Ag
 	var config Config
 	err := fetcher.Fetch(&config)
 	if err != nil {
-		buildkite.LogFailuref("plugin configuration error: %s\n", err.Error())
-		return err
+		return fmt.Errorf("plugin configuration error: %w", err)
 	}
 	annotation := config.Message
 
 	buildkite.Logf("Annotating with message: %s\n", annotation)
 
 	err = agent.Annotate(ctx, annotation, "info", "message")
 	if err != nil {
-		buildkite.LogFailuref("buildkite annotation error: %s\n", err.Error())
-		return err
+		return fmt.Errorf("buildkite annotation error: %w", err)
 	}
 
 	buildkite.Log("done.")