package tfdiags import ( "bytes" "fmt" "github.com/hashicorp/errwrap" multierror "github.com/hashicorp/go-multierror" "github.com/hashicorp/hcl2/hcl" ) // Diagnostics is a list of diagnostics. Diagnostics is intended to be used // where a Go "error" might normally be used, allowing richer information // to be conveyed (more context, support for warnings). // // A nil Diagnostics is a valid, empty diagnostics list, thus allowing // heap allocation to be avoided in the common case where there are no // diagnostics to report at all. type Diagnostics []Diagnostic // Append is the main interface for constructing Diagnostics lists, taking // an existing list (which may be nil) and appending the new objects to it // after normalizing them to be implementations of Diagnostic. // // The usual pattern for a function that natively "speaks" diagnostics is: // // // Create a nil Diagnostics at the start of the function // var diags diag.Diagnostics // // // At later points, build on it if errors / warnings occur: // foo, err := DoSomethingRisky() // if err != nil { // diags = diags.Append(err) // } // // // Eventually return the result and diagnostics in place of error // return result, diags // // Append accepts a variety of different diagnostic-like types, including // native Go errors and HCL diagnostics. It also knows how to unwrap // a multierror.Error into separate error diagnostics. It can be passed // another Diagnostics to concatenate the two lists. If given something // it cannot handle, this function will panic. func (diags Diagnostics) Append(new ...interface{}) Diagnostics { for _, item := range new { if item == nil { continue } switch ti := item.(type) { case Diagnostic: diags = append(diags, ti) case Diagnostics: diags = append(diags, ti...) // flatten case diagnosticsAsError: diags = diags.Append(ti.Diagnostics) // unwrap case hcl.Diagnostics: for _, hclDiag := range ti { diags = append(diags, hclDiagnostic{hclDiag}) } case *hcl.Diagnostic: diags = append(diags, hclDiagnostic{ti}) case *multierror.Error: for _, err := range ti.Errors { diags = append(diags, nativeError{err}) } case error: switch { case errwrap.ContainsType(ti, Diagnostics(nil)): // If we have an errwrap wrapper with a Diagnostics hiding // inside then we'll unpick it here to get access to the // individual diagnostics. diags = diags.Append(errwrap.GetType(ti, Diagnostics(nil))) case errwrap.ContainsType(ti, hcl.Diagnostics(nil)): // Likewise, if we have HCL diagnostics we'll unpick that too. diags = diags.Append(errwrap.GetType(ti, hcl.Diagnostics(nil))) default: diags = append(diags, nativeError{ti}) } default: panic(fmt.Errorf("can't construct diagnostic(s) from %T", item)) } } // Given the above, we should never end up with a non-nil empty slice // here, but we'll make sure of that so callers can rely on empty == nil if len(diags) == 0 { return nil } return diags } // HasErrors returns true if any of the diagnostics in the list have // a severity of Error. func (diags Diagnostics) HasErrors() bool { for _, diag := range diags { if diag.Severity() == Error { return true } } return false } // ForRPC returns a version of the receiver that has been simplified so that // it is friendly to RPC protocols. // // Currently this means that it can be serialized with encoding/gob and // subsequently re-inflated. It may later grow to include other serialization // formats. // // Note that this loses information about the original objects used to // construct the diagnostics, so e.g. the errwrap API will not work as // expected on an error-wrapped Diagnostics that came from ForRPC. func (diags Diagnostics) ForRPC() Diagnostics { ret := make(Diagnostics, len(diags)) for i := range diags { ret[i] = makeRPCFriendlyDiag(diags[i]) } return ret } // Err flattens a diagnostics list into a single Go error, or to nil // if the diagnostics list does not include any error-level diagnostics. // // This can be used to smuggle diagnostics through an API that deals in // native errors, but unfortunately it will lose naked warnings (warnings // that aren't accompanied by at least one error) since such APIs have no // mechanism through which to report these. // // return result, diags.Error() func (diags Diagnostics) Err() error { if !diags.HasErrors() { return nil } return diagnosticsAsError{diags} } // ErrWithWarnings is similar to Err except that it will also return a non-nil // error if the receiver contains only warnings. // // In the warnings-only situation, the result is guaranteed to be of dynamic // type NonFatalError, allowing diagnostics-aware callers to type-assert // and unwrap it, treating it as non-fatal. // // This should be used only in contexts where the caller is able to recognize // and handle NonFatalError. For normal callers that expect a lack of errors // to be signaled by nil, use just Diagnostics.Err. func (diags Diagnostics) ErrWithWarnings() error { if len(diags) == 0 { return nil } if diags.HasErrors() { return diags.Err() } return NonFatalError{diags} } // NonFatalErr is similar to Err except that it always returns either nil // (if there are no diagnostics at all) or NonFatalError. // // This allows diagnostics to be returned over an error return channel while // being explicit that the diagnostics should not halt processing. // // This should be used only in contexts where the caller is able to recognize // and handle NonFatalError. For normal callers that expect a lack of errors // to be signaled by nil, use just Diagnostics.Err. func (diags Diagnostics) NonFatalErr() error { if len(diags) == 0 { return nil } return NonFatalError{diags} } type diagnosticsAsError struct { Diagnostics } func (dae diagnosticsAsError) Error() string { diags := dae.Diagnostics switch { case len(diags) == 0: // should never happen, since we don't create this wrapper if // there are no diagnostics in the list. return "no errors" case len(diags) == 1: desc := diags[0].Description() if desc.Detail == "" { return desc.Summary } return fmt.Sprintf("%s: %s", desc.Summary, desc.Detail) default: var ret bytes.Buffer fmt.Fprintf(&ret, "%d problems:\n", len(diags)) for _, diag := range dae.Diagnostics { desc := diag.Description() if desc.Detail == "" { fmt.Fprintf(&ret, "\n- %s", desc.Summary) } else { fmt.Fprintf(&ret, "\n- %s: %s", desc.Summary, desc.Detail) } } return ret.String() } } // WrappedErrors is an implementation of errwrap.Wrapper so that an error-wrapped // diagnostics object can be picked apart by errwrap-aware code. func (dae diagnosticsAsError) WrappedErrors() []error { var errs []error for _, diag := range dae.Diagnostics { if wrapper, isErr := diag.(nativeError); isErr { errs = append(errs, wrapper.err) } } return errs } // NonFatalError is a special error type, returned by // Diagnostics.ErrWithWarnings and Diagnostics.NonFatalErr, // that indicates that the wrapped diagnostics should be treated as non-fatal. // Callers can conditionally type-assert an error to this type in order to // detect the non-fatal scenario and handle it in a different way. type NonFatalError struct { Diagnostics } func (woe NonFatalError) Error() string { diags := woe.Diagnostics switch { case len(diags) == 0: // should never happen, since we don't create this wrapper if // there are no diagnostics in the list. return "no errors or warnings" case len(diags) == 1: desc := diags[0].Description() if desc.Detail == "" { return desc.Summary } return fmt.Sprintf("%s: %s", desc.Summary, desc.Detail) default: var ret bytes.Buffer if diags.HasErrors() { fmt.Fprintf(&ret, "%d problems:\n", len(diags)) } else { fmt.Fprintf(&ret, "%d warnings:\n", len(diags)) } for _, diag := range woe.Diagnostics { desc := diag.Description() if desc.Detail == "" { fmt.Fprintf(&ret, "\n- %s", desc.Summary) } else { fmt.Fprintf(&ret, "\n- %s: %s", desc.Summary, desc.Detail) } } return ret.String() } }