Update all dependencies.

* Switch to using kingpin for CLI interface as upstream Prometheus has moved
  that way too.

vendor/github.com/lib/pq/copy.go

@@ -13,6 +13,7 @@ var (
 	errBinaryCopyNotSupported     = errors.New("pq: only text format supported for COPY")
 	errCopyToNotSupported         = errors.New("pq: COPY TO is not supported")
 	errCopyNotSupportedOutsideTxn = errors.New("pq: COPY is only allowed inside a transaction")
+	errCopyInProgress             = errors.New("pq: COPY in progress")
 )
 
 // CopyIn creates a COPY FROM statement which can be prepared with
@@ -96,13 +97,13 @@ awaitCopyInResponse:
 			err = parseError(r)
 		case 'Z':
 			if err == nil {
-				cn.bad = true
+				ci.setBad()
 				errorf("unexpected ReadyForQuery in response to COPY")
 			}
 			cn.processReadyForQuery(r)
 			return nil, err
 		default:
-			cn.bad = true
+			ci.setBad()
 			errorf("unknown response for copy query: %q", t)
 		}
 	}
@@ -121,7 +122,7 @@ awaitCopyInResponse:
 			cn.processReadyForQuery(r)
 			return nil, err
 		default:
-			cn.bad = true
+			ci.setBad()
 			errorf("unknown response for CopyFail: %q", t)
 		}
 	}
@@ -142,7 +143,7 @@ func (ci *copyin) resploop() {
 		var r readBuf
 		t, err := ci.cn.recvMessage(&r)
 		if err != nil {
-			ci.cn.bad = true
+			ci.setBad()
 			ci.setError(err)
 			ci.done <- true
 			return
@@ -160,7 +161,7 @@ func (ci *copyin) resploop() {
 			err := parseError(&r)
 			ci.setError(err)
 		default:
-			ci.cn.bad = true
+			ci.setBad()
 			ci.setError(fmt.Errorf("unknown response during CopyIn: %q", t))
 			ci.done <- true
 			return
@@ -168,6 +169,19 @@ func (ci *copyin) resploop() {
 	}
 }
 
+func (ci *copyin) setBad() {
+	ci.Lock()
+	ci.cn.bad = true
+	ci.Unlock()
+}
+
+func (ci *copyin) isBad() bool {
+	ci.Lock()
+	b := ci.cn.bad
+	ci.Unlock()
+	return b
+}
+
 func (ci *copyin) isErrorSet() bool {
 	ci.Lock()
 	isSet := (ci.err != nil)
@@ -205,7 +219,7 @@ func (ci *copyin) Exec(v []driver.Value) (r driver.Result, err error) {
 		return nil, errCopyInClosed
 	}
 
-	if ci.cn.bad {
+	if ci.isBad() {
 		return nil, driver.ErrBadConn
 	}
 	defer ci.cn.errRecover(&err)
@@ -215,9 +229,7 @@ func (ci *copyin) Exec(v []driver.Value) (r driver.Result, err error) {
 	}
 
 	if len(v) == 0 {
-		err = ci.Close()
-		ci.closed = true
-		return nil, err
+		return nil, ci.Close()
 	}
 
 	numValues := len(v)
@@ -240,11 +252,12 @@ func (ci *copyin) Exec(v []driver.Value) (r driver.Result, err error) {
 }
 
 func (ci *copyin) Close() (err error) {
-	if ci.closed {
-		return errCopyInClosed
+	if ci.closed { // Don't do anything, we're already closed
+		return nil
 	}
+	ci.closed = true
 
-	if ci.cn.bad {
+	if ci.isBad() {
 		return driver.ErrBadConn
 	}
 	defer ci.cn.errRecover(&err)
@@ -259,6 +272,7 @@ func (ci *copyin) Close() (err error) {
 	}
 
 	<-ci.done
+	ci.cn.inCopy = false
 
 	if ci.isErrorSet() {
 		err = ci.err