feat(diag): adds diag builder for a developer friendly API.

Author: matthewhartstonge

diag/builder.go

@@ -0,0 +1,45 @@
+package diag
+
+// Builder provides a log entry building api. This should not be used directly,
+// but should be used by calling the component based method on the supplied
+// Diagnostics.
+type Builder struct {
+	d *Diagnostics
+	e *Diagnostic
+}
+
+func (b *Builder) Fatal(detail, summary string) *Diagnostics {
+	return b.build(SeverityFatal, detail, summary)
+}
+
+func (b *Builder) Error(detail, summary string) *Diagnostics {
+	return b.build(SeverityError, detail, summary)
+}
+
+func (b *Builder) Warn(detail, summary string) *Diagnostics {
+	return b.build(SeverityWarn, detail, summary)
+}
+
+func (b *Builder) Info(detail, summary string) *Diagnostics {
+	return b.build(SeverityInfo, detail, summary)
+}
+
+func (b *Builder) Debug(detail, summary string) *Diagnostics {
+	return b.build(SeverityDebug, detail, summary)
+}
+
+func (b *Builder) Trace(detail, summary string) *Diagnostics {
+	return b.build(SeverityTrace, detail, summary)
+}
+
+func (b *Builder) build(sev Severity, detail, summary string) *Diagnostics {
+	diags, diag := b.d, b.e
+
+	diag.Severity = sev
+	diag.Detail = detail
+	diag.Summary = summary
+
+	diags.Append(*diag)
+
+	return diags
+}

diag/diagnostics.go

@@ -8,6 +8,35 @@ func (d *Diagnostics) Append(diags ...Diagnostic) {
 	*d = append(*d, diags...)
 }
 
+// GlobalFile enables building up a diagnostic message for a global
+// configuration file value.
+func (d *Diagnostics) GlobalFile(path string) *Builder {
+	return d.builder(ComponentGlobalFile, path)
+}
+
+// Env enables building up a diagnostic message for an environment variable value.
+func (d *Diagnostics) Env(path string) *Builder {
+	return d.builder(ComponentEnvVar, path)
+}
+
+// LocalFile enables building up a diagnostic message for a local configuration
+// file value.
+func (d *Diagnostics) LocalFile(path string) *Builder {
+	return d.builder(ComponentLocalFile, path)
+}
+
+// Flag enables building up a diagnostic message for a CLI flag value.
+func (d *Diagnostics) Flag(path string) *Builder {
+	return d.builder(ComponentFlag, path)
+}
+
+func (d *Diagnostics) builder(component Component, path string) *Builder {
+	return &Builder{
+		d: d,
+		e: &Diagnostic{Component: component, Path: path},
+	}
+}
+
 // Fatals returns all diagnostic entries at SeverityFatal level.
 func (d *Diagnostics) Fatals() []Diagnostic {
 	return d.getDiagsWithLevel(SeverityFatal)