[VOL-2538] Logging - Implement dynamic log levels in ofagent
Change-Id: I9582230d9d3c34ea84339fddf2b2f3b3d2804808
diff --git a/vendor/github.com/hashicorp/go-immutable-radix/iradix.go b/vendor/github.com/hashicorp/go-immutable-radix/iradix.go
new file mode 100644
index 0000000..e5e6e57
--- /dev/null
+++ b/vendor/github.com/hashicorp/go-immutable-radix/iradix.go
@@ -0,0 +1,662 @@
+package iradix
+
+import (
+ "bytes"
+ "strings"
+
+ "github.com/hashicorp/golang-lru/simplelru"
+)
+
+const (
+ // defaultModifiedCache is the default size of the modified node
+ // cache used per transaction. This is used to cache the updates
+ // to the nodes near the root, while the leaves do not need to be
+ // cached. This is important for very large transactions to prevent
+ // the modified cache from growing to be enormous. This is also used
+ // to set the max size of the mutation notify maps since those should
+ // also be bounded in a similar way.
+ defaultModifiedCache = 8192
+)
+
+// Tree implements an immutable radix tree. This can be treated as a
+// Dictionary abstract data type. The main advantage over a standard
+// hash map is prefix-based lookups and ordered iteration. The immutability
+// means that it is safe to concurrently read from a Tree without any
+// coordination.
+type Tree struct {
+ root *Node
+ size int
+}
+
+// New returns an empty Tree
+func New() *Tree {
+ t := &Tree{
+ root: &Node{
+ mutateCh: make(chan struct{}),
+ },
+ }
+ return t
+}
+
+// Len is used to return the number of elements in the tree
+func (t *Tree) Len() int {
+ return t.size
+}
+
+// Txn is a transaction on the tree. This transaction is applied
+// atomically and returns a new tree when committed. A transaction
+// is not thread safe, and should only be used by a single goroutine.
+type Txn struct {
+ // root is the modified root for the transaction.
+ root *Node
+
+ // snap is a snapshot of the root node for use if we have to run the
+ // slow notify algorithm.
+ snap *Node
+
+ // size tracks the size of the tree as it is modified during the
+ // transaction.
+ size int
+
+ // writable is a cache of writable nodes that have been created during
+ // the course of the transaction. This allows us to re-use the same
+ // nodes for further writes and avoid unnecessary copies of nodes that
+ // have never been exposed outside the transaction. This will only hold
+ // up to defaultModifiedCache number of entries.
+ writable *simplelru.LRU
+
+ // trackChannels is used to hold channels that need to be notified to
+ // signal mutation of the tree. This will only hold up to
+ // defaultModifiedCache number of entries, after which we will set the
+ // trackOverflow flag, which will cause us to use a more expensive
+ // algorithm to perform the notifications. Mutation tracking is only
+ // performed if trackMutate is true.
+ trackChannels map[chan struct{}]struct{}
+ trackOverflow bool
+ trackMutate bool
+}
+
+// Txn starts a new transaction that can be used to mutate the tree
+func (t *Tree) Txn() *Txn {
+ txn := &Txn{
+ root: t.root,
+ snap: t.root,
+ size: t.size,
+ }
+ return txn
+}
+
+// TrackMutate can be used to toggle if mutations are tracked. If this is enabled
+// then notifications will be issued for affected internal nodes and leaves when
+// the transaction is committed.
+func (t *Txn) TrackMutate(track bool) {
+ t.trackMutate = track
+}
+
+// trackChannel safely attempts to track the given mutation channel, setting the
+// overflow flag if we can no longer track any more. This limits the amount of
+// state that will accumulate during a transaction and we have a slower algorithm
+// to switch to if we overflow.
+func (t *Txn) trackChannel(ch chan struct{}) {
+ // In overflow, make sure we don't store any more objects.
+ if t.trackOverflow {
+ return
+ }
+
+ // If this would overflow the state we reject it and set the flag (since
+ // we aren't tracking everything that's required any longer).
+ if len(t.trackChannels) >= defaultModifiedCache {
+ // Mark that we are in the overflow state
+ t.trackOverflow = true
+
+ // Clear the map so that the channels can be garbage collected. It is
+ // safe to do this since we have already overflowed and will be using
+ // the slow notify algorithm.
+ t.trackChannels = nil
+ return
+ }
+
+ // Create the map on the fly when we need it.
+ if t.trackChannels == nil {
+ t.trackChannels = make(map[chan struct{}]struct{})
+ }
+
+ // Otherwise we are good to track it.
+ t.trackChannels[ch] = struct{}{}
+}
+
+// writeNode returns a node to be modified, if the current node has already been
+// modified during the course of the transaction, it is used in-place. Set
+// forLeafUpdate to true if you are getting a write node to update the leaf,
+// which will set leaf mutation tracking appropriately as well.
+func (t *Txn) writeNode(n *Node, forLeafUpdate bool) *Node {
+ // Ensure the writable set exists.
+ if t.writable == nil {
+ lru, err := simplelru.NewLRU(defaultModifiedCache, nil)
+ if err != nil {
+ panic(err)
+ }
+ t.writable = lru
+ }
+
+ // If this node has already been modified, we can continue to use it
+ // during this transaction. We know that we don't need to track it for
+ // a node update since the node is writable, but if this is for a leaf
+ // update we track it, in case the initial write to this node didn't
+ // update the leaf.
+ if _, ok := t.writable.Get(n); ok {
+ if t.trackMutate && forLeafUpdate && n.leaf != nil {
+ t.trackChannel(n.leaf.mutateCh)
+ }
+ return n
+ }
+
+ // Mark this node as being mutated.
+ if t.trackMutate {
+ t.trackChannel(n.mutateCh)
+ }
+
+ // Mark its leaf as being mutated, if appropriate.
+ if t.trackMutate && forLeafUpdate && n.leaf != nil {
+ t.trackChannel(n.leaf.mutateCh)
+ }
+
+ // Copy the existing node. If you have set forLeafUpdate it will be
+ // safe to replace this leaf with another after you get your node for
+ // writing. You MUST replace it, because the channel associated with
+ // this leaf will be closed when this transaction is committed.
+ nc := &Node{
+ mutateCh: make(chan struct{}),
+ leaf: n.leaf,
+ }
+ if n.prefix != nil {
+ nc.prefix = make([]byte, len(n.prefix))
+ copy(nc.prefix, n.prefix)
+ }
+ if len(n.edges) != 0 {
+ nc.edges = make([]edge, len(n.edges))
+ copy(nc.edges, n.edges)
+ }
+
+ // Mark this node as writable.
+ t.writable.Add(nc, nil)
+ return nc
+}
+
+// Visit all the nodes in the tree under n, and add their mutateChannels to the transaction
+// Returns the size of the subtree visited
+func (t *Txn) trackChannelsAndCount(n *Node) int {
+ // Count only leaf nodes
+ leaves := 0
+ if n.leaf != nil {
+ leaves = 1
+ }
+ // Mark this node as being mutated.
+ if t.trackMutate {
+ t.trackChannel(n.mutateCh)
+ }
+
+ // Mark its leaf as being mutated, if appropriate.
+ if t.trackMutate && n.leaf != nil {
+ t.trackChannel(n.leaf.mutateCh)
+ }
+
+ // Recurse on the children
+ for _, e := range n.edges {
+ leaves += t.trackChannelsAndCount(e.node)
+ }
+ return leaves
+}
+
+// mergeChild is called to collapse the given node with its child. This is only
+// called when the given node is not a leaf and has a single edge.
+func (t *Txn) mergeChild(n *Node) {
+ // Mark the child node as being mutated since we are about to abandon
+ // it. We don't need to mark the leaf since we are retaining it if it
+ // is there.
+ e := n.edges[0]
+ child := e.node
+ if t.trackMutate {
+ t.trackChannel(child.mutateCh)
+ }
+
+ // Merge the nodes.
+ n.prefix = concat(n.prefix, child.prefix)
+ n.leaf = child.leaf
+ if len(child.edges) != 0 {
+ n.edges = make([]edge, len(child.edges))
+ copy(n.edges, child.edges)
+ } else {
+ n.edges = nil
+ }
+}
+
+// insert does a recursive insertion
+func (t *Txn) insert(n *Node, k, search []byte, v interface{}) (*Node, interface{}, bool) {
+ // Handle key exhaustion
+ if len(search) == 0 {
+ var oldVal interface{}
+ didUpdate := false
+ if n.isLeaf() {
+ oldVal = n.leaf.val
+ didUpdate = true
+ }
+
+ nc := t.writeNode(n, true)
+ nc.leaf = &leafNode{
+ mutateCh: make(chan struct{}),
+ key: k,
+ val: v,
+ }
+ return nc, oldVal, didUpdate
+ }
+
+ // Look for the edge
+ idx, child := n.getEdge(search[0])
+
+ // No edge, create one
+ if child == nil {
+ e := edge{
+ label: search[0],
+ node: &Node{
+ mutateCh: make(chan struct{}),
+ leaf: &leafNode{
+ mutateCh: make(chan struct{}),
+ key: k,
+ val: v,
+ },
+ prefix: search,
+ },
+ }
+ nc := t.writeNode(n, false)
+ nc.addEdge(e)
+ return nc, nil, false
+ }
+
+ // Determine longest prefix of the search key on match
+ commonPrefix := longestPrefix(search, child.prefix)
+ if commonPrefix == len(child.prefix) {
+ search = search[commonPrefix:]
+ newChild, oldVal, didUpdate := t.insert(child, k, search, v)
+ if newChild != nil {
+ nc := t.writeNode(n, false)
+ nc.edges[idx].node = newChild
+ return nc, oldVal, didUpdate
+ }
+ return nil, oldVal, didUpdate
+ }
+
+ // Split the node
+ nc := t.writeNode(n, false)
+ splitNode := &Node{
+ mutateCh: make(chan struct{}),
+ prefix: search[:commonPrefix],
+ }
+ nc.replaceEdge(edge{
+ label: search[0],
+ node: splitNode,
+ })
+
+ // Restore the existing child node
+ modChild := t.writeNode(child, false)
+ splitNode.addEdge(edge{
+ label: modChild.prefix[commonPrefix],
+ node: modChild,
+ })
+ modChild.prefix = modChild.prefix[commonPrefix:]
+
+ // Create a new leaf node
+ leaf := &leafNode{
+ mutateCh: make(chan struct{}),
+ key: k,
+ val: v,
+ }
+
+ // If the new key is a subset, add to to this node
+ search = search[commonPrefix:]
+ if len(search) == 0 {
+ splitNode.leaf = leaf
+ return nc, nil, false
+ }
+
+ // Create a new edge for the node
+ splitNode.addEdge(edge{
+ label: search[0],
+ node: &Node{
+ mutateCh: make(chan struct{}),
+ leaf: leaf,
+ prefix: search,
+ },
+ })
+ return nc, nil, false
+}
+
+// delete does a recursive deletion
+func (t *Txn) delete(parent, n *Node, search []byte) (*Node, *leafNode) {
+ // Check for key exhaustion
+ if len(search) == 0 {
+ if !n.isLeaf() {
+ return nil, nil
+ }
+ // Copy the pointer in case we are in a transaction that already
+ // modified this node since the node will be reused. Any changes
+ // made to the node will not affect returning the original leaf
+ // value.
+ oldLeaf := n.leaf
+
+ // Remove the leaf node
+ nc := t.writeNode(n, true)
+ nc.leaf = nil
+
+ // Check if this node should be merged
+ if n != t.root && len(nc.edges) == 1 {
+ t.mergeChild(nc)
+ }
+ return nc, oldLeaf
+ }
+
+ // Look for an edge
+ label := search[0]
+ idx, child := n.getEdge(label)
+ if child == nil || !bytes.HasPrefix(search, child.prefix) {
+ return nil, nil
+ }
+
+ // Consume the search prefix
+ search = search[len(child.prefix):]
+ newChild, leaf := t.delete(n, child, search)
+ if newChild == nil {
+ return nil, nil
+ }
+
+ // Copy this node. WATCH OUT - it's safe to pass "false" here because we
+ // will only ADD a leaf via nc.mergeChild() if there isn't one due to
+ // the !nc.isLeaf() check in the logic just below. This is pretty subtle,
+ // so be careful if you change any of the logic here.
+ nc := t.writeNode(n, false)
+
+ // Delete the edge if the node has no edges
+ if newChild.leaf == nil && len(newChild.edges) == 0 {
+ nc.delEdge(label)
+ if n != t.root && len(nc.edges) == 1 && !nc.isLeaf() {
+ t.mergeChild(nc)
+ }
+ } else {
+ nc.edges[idx].node = newChild
+ }
+ return nc, leaf
+}
+
+// delete does a recursive deletion
+func (t *Txn) deletePrefix(parent, n *Node, search []byte) (*Node, int) {
+ // Check for key exhaustion
+ if len(search) == 0 {
+ nc := t.writeNode(n, true)
+ if n.isLeaf() {
+ nc.leaf = nil
+ }
+ nc.edges = nil
+ return nc, t.trackChannelsAndCount(n)
+ }
+
+ // Look for an edge
+ label := search[0]
+ idx, child := n.getEdge(label)
+ // We make sure that either the child node's prefix starts with the search term, or the search term starts with the child node's prefix
+ // Need to do both so that we can delete prefixes that don't correspond to any node in the tree
+ if child == nil || (!bytes.HasPrefix(child.prefix, search) && !bytes.HasPrefix(search, child.prefix)) {
+ return nil, 0
+ }
+
+ // Consume the search prefix
+ if len(child.prefix) > len(search) {
+ search = []byte("")
+ } else {
+ search = search[len(child.prefix):]
+ }
+ newChild, numDeletions := t.deletePrefix(n, child, search)
+ if newChild == nil {
+ return nil, 0
+ }
+ // Copy this node. WATCH OUT - it's safe to pass "false" here because we
+ // will only ADD a leaf via nc.mergeChild() if there isn't one due to
+ // the !nc.isLeaf() check in the logic just below. This is pretty subtle,
+ // so be careful if you change any of the logic here.
+
+ nc := t.writeNode(n, false)
+
+ // Delete the edge if the node has no edges
+ if newChild.leaf == nil && len(newChild.edges) == 0 {
+ nc.delEdge(label)
+ if n != t.root && len(nc.edges) == 1 && !nc.isLeaf() {
+ t.mergeChild(nc)
+ }
+ } else {
+ nc.edges[idx].node = newChild
+ }
+ return nc, numDeletions
+}
+
+// Insert is used to add or update a given key. The return provides
+// the previous value and a bool indicating if any was set.
+func (t *Txn) Insert(k []byte, v interface{}) (interface{}, bool) {
+ newRoot, oldVal, didUpdate := t.insert(t.root, k, k, v)
+ if newRoot != nil {
+ t.root = newRoot
+ }
+ if !didUpdate {
+ t.size++
+ }
+ return oldVal, didUpdate
+}
+
+// Delete is used to delete a given key. Returns the old value if any,
+// and a bool indicating if the key was set.
+func (t *Txn) Delete(k []byte) (interface{}, bool) {
+ newRoot, leaf := t.delete(nil, t.root, k)
+ if newRoot != nil {
+ t.root = newRoot
+ }
+ if leaf != nil {
+ t.size--
+ return leaf.val, true
+ }
+ return nil, false
+}
+
+// DeletePrefix is used to delete an entire subtree that matches the prefix
+// This will delete all nodes under that prefix
+func (t *Txn) DeletePrefix(prefix []byte) bool {
+ newRoot, numDeletions := t.deletePrefix(nil, t.root, prefix)
+ if newRoot != nil {
+ t.root = newRoot
+ t.size = t.size - numDeletions
+ return true
+ }
+ return false
+
+}
+
+// Root returns the current root of the radix tree within this
+// transaction. The root is not safe across insert and delete operations,
+// but can be used to read the current state during a transaction.
+func (t *Txn) Root() *Node {
+ return t.root
+}
+
+// Get is used to lookup a specific key, returning
+// the value and if it was found
+func (t *Txn) Get(k []byte) (interface{}, bool) {
+ return t.root.Get(k)
+}
+
+// GetWatch is used to lookup a specific key, returning
+// the watch channel, value and if it was found
+func (t *Txn) GetWatch(k []byte) (<-chan struct{}, interface{}, bool) {
+ return t.root.GetWatch(k)
+}
+
+// Commit is used to finalize the transaction and return a new tree. If mutation
+// tracking is turned on then notifications will also be issued.
+func (t *Txn) Commit() *Tree {
+ nt := t.CommitOnly()
+ if t.trackMutate {
+ t.Notify()
+ }
+ return nt
+}
+
+// CommitOnly is used to finalize the transaction and return a new tree, but
+// does not issue any notifications until Notify is called.
+func (t *Txn) CommitOnly() *Tree {
+ nt := &Tree{t.root, t.size}
+ t.writable = nil
+ return nt
+}
+
+// slowNotify does a complete comparison of the before and after trees in order
+// to trigger notifications. This doesn't require any additional state but it
+// is very expensive to compute.
+func (t *Txn) slowNotify() {
+ snapIter := t.snap.rawIterator()
+ rootIter := t.root.rawIterator()
+ for snapIter.Front() != nil || rootIter.Front() != nil {
+ // If we've exhausted the nodes in the old snapshot, we know
+ // there's nothing remaining to notify.
+ if snapIter.Front() == nil {
+ return
+ }
+ snapElem := snapIter.Front()
+
+ // If we've exhausted the nodes in the new root, we know we need
+ // to invalidate everything that remains in the old snapshot. We
+ // know from the loop condition there's something in the old
+ // snapshot.
+ if rootIter.Front() == nil {
+ close(snapElem.mutateCh)
+ if snapElem.isLeaf() {
+ close(snapElem.leaf.mutateCh)
+ }
+ snapIter.Next()
+ continue
+ }
+
+ // Do one string compare so we can check the various conditions
+ // below without repeating the compare.
+ cmp := strings.Compare(snapIter.Path(), rootIter.Path())
+
+ // If the snapshot is behind the root, then we must have deleted
+ // this node during the transaction.
+ if cmp < 0 {
+ close(snapElem.mutateCh)
+ if snapElem.isLeaf() {
+ close(snapElem.leaf.mutateCh)
+ }
+ snapIter.Next()
+ continue
+ }
+
+ // If the snapshot is ahead of the root, then we must have added
+ // this node during the transaction.
+ if cmp > 0 {
+ rootIter.Next()
+ continue
+ }
+
+ // If we have the same path, then we need to see if we mutated a
+ // node and possibly the leaf.
+ rootElem := rootIter.Front()
+ if snapElem != rootElem {
+ close(snapElem.mutateCh)
+ if snapElem.leaf != nil && (snapElem.leaf != rootElem.leaf) {
+ close(snapElem.leaf.mutateCh)
+ }
+ }
+ snapIter.Next()
+ rootIter.Next()
+ }
+}
+
+// Notify is used along with TrackMutate to trigger notifications. This must
+// only be done once a transaction is committed via CommitOnly, and it is called
+// automatically by Commit.
+func (t *Txn) Notify() {
+ if !t.trackMutate {
+ return
+ }
+
+ // If we've overflowed the tracking state we can't use it in any way and
+ // need to do a full tree compare.
+ if t.trackOverflow {
+ t.slowNotify()
+ } else {
+ for ch := range t.trackChannels {
+ close(ch)
+ }
+ }
+
+ // Clean up the tracking state so that a re-notify is safe (will trigger
+ // the else clause above which will be a no-op).
+ t.trackChannels = nil
+ t.trackOverflow = false
+}
+
+// Insert is used to add or update a given key. The return provides
+// the new tree, previous value and a bool indicating if any was set.
+func (t *Tree) Insert(k []byte, v interface{}) (*Tree, interface{}, bool) {
+ txn := t.Txn()
+ old, ok := txn.Insert(k, v)
+ return txn.Commit(), old, ok
+}
+
+// Delete is used to delete a given key. Returns the new tree,
+// old value if any, and a bool indicating if the key was set.
+func (t *Tree) Delete(k []byte) (*Tree, interface{}, bool) {
+ txn := t.Txn()
+ old, ok := txn.Delete(k)
+ return txn.Commit(), old, ok
+}
+
+// DeletePrefix is used to delete all nodes starting with a given prefix. Returns the new tree,
+// and a bool indicating if the prefix matched any nodes
+func (t *Tree) DeletePrefix(k []byte) (*Tree, bool) {
+ txn := t.Txn()
+ ok := txn.DeletePrefix(k)
+ return txn.Commit(), ok
+}
+
+// Root returns the root node of the tree which can be used for richer
+// query operations.
+func (t *Tree) Root() *Node {
+ return t.root
+}
+
+// Get is used to lookup a specific key, returning
+// the value and if it was found
+func (t *Tree) Get(k []byte) (interface{}, bool) {
+ return t.root.Get(k)
+}
+
+// longestPrefix finds the length of the shared prefix
+// of two strings
+func longestPrefix(k1, k2 []byte) int {
+ max := len(k1)
+ if l := len(k2); l < max {
+ max = l
+ }
+ var i int
+ for i = 0; i < max; i++ {
+ if k1[i] != k2[i] {
+ break
+ }
+ }
+ return i
+}
+
+// concat two byte slices, returning a third new copy
+func concat(a, b []byte) []byte {
+ c := make([]byte, len(a)+len(b))
+ copy(c, a)
+ copy(c[len(a):], b)
+ return c
+}