From d3f7af71147f92226d2e57540467202f3b8f2439 Mon Sep 17 00:00:00 2001
From: teor <teor@riseup.net>
Date: Wed, 2 Sep 2020 17:34:33 +1000
Subject: [PATCH] Add log filters which provide block info

These filters use zcash-cli to annotate hashes with the corresponding
block info.

They are useful when the local zebrad instance hasn't downloaded or
parsed the blocks in its logs, or when the zebrad logs just provide a
hash. The filter provides the height, time, previous, and next blocks.
---
 zebra-utils/zebrad-hash-lookup | 36 ++++++++++++++++++++++++++++++++++
 zebra-utils/zebrad-log-filter  | 31 +++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+)
 create mode 100755 zebra-utils/zebrad-hash-lookup
 create mode 100755 zebra-utils/zebrad-log-filter

diff --git a/zebra-utils/zebrad-hash-lookup b/zebra-utils/zebrad-hash-lookup
new file mode 100755
index 00000000..85030d42
--- /dev/null
+++ b/zebra-utils/zebrad-hash-lookup
@@ -0,0 +1,36 @@
+#!/bin/bash
+
+set -euo pipefail
+
+# Reads stdin or the file $1, looks lines up as hashes, then outputs block info
+# for each hash. Uses the zcash-cli command for block lookups.
+
+ZEBRAD="${ZEBRAD:-zebrad}"
+ZCASH_CLI="${ZCASH_CLI:-zcash-cli}"
+
+while read hash; do
+    zcashd_hash=$($ZEBRAD revhex "$hash")
+    header=$($ZCASH_CLI getblockheader "$zcashd_hash" 2>&1 || true)
+
+    if echo "$header" | jq . > /dev/null 2> /dev/null; then
+        high=$(echo "$header" | jq -r '"\(.height)"')
+        time=$(echo "$header" | jq -r '"\(.time|todate)"')
+        prev=$(echo "$header" | jq -r '"\(.previousblockhash)"')
+        next=$(echo "$header" | jq -r '"\(.nextblockhash)"')
+
+        # use Zebra hash order
+        if [ "$prev" != 'null' ]; then
+            prev=$($ZEBRAD revhex "$prev")
+        fi
+        if [ "$next" != 'null' ]; then
+            next=$($ZEBRAD revhex "$next")
+        fi
+
+        printf 'high: %s\ntime: %s\nhash: %s\nprev: %s\nnext: %s\n' \
+               "$high" "$time" "$hash" "$prev" "$next"
+    else
+        # Handle lookup errors
+        printf 'hash: %s\n%s\n' \
+               "$hash" "$header"
+    fi
+done < "${1:-/dev/stdin}"
diff --git a/zebra-utils/zebrad-log-filter b/zebra-utils/zebrad-log-filter
new file mode 100755
index 00000000..931d0a32
--- /dev/null
+++ b/zebra-utils/zebrad-log-filter
@@ -0,0 +1,31 @@
+#!/bin/bash
+
+set -euo pipefail
+
+# Reads stdin or the file $1, replacing hashes with block info
+#
+# Uses zebrad-hash-lookup, which uses zcash-cli.
+#
+# Usage:
+#   zebrad start | zebrad-log-filter
+#   ZCASH_CLI="zcash-cli -testnet" zebrad start | zebrad-log-filter
+
+# Find GNU sed
+if command -v gsed > /dev/null; then
+    GNU_SED=${GNU_SED:-gsed}
+else
+    # Just assume it's GNU sed
+    GNU_SED=${GNU_SED:-sed}
+fi
+
+while read line; do
+    # Put each hash on a separate line, then expand them
+    echo "$line" | \
+        $GNU_SED -r \
+            's/([0-9a-f]{64})/\n\1/g' | \
+        $GNU_SED -r \
+            's/(.*)([0-9a-f]{64})(.*)/ \
+                echo -n '\''\1'\''; \
+                echo '\''\2'\'' | zebrad-hash-lookup; \
+                echo -n '\''\3'\''; /e'
+done < "${1:-/dev/stdin}"