mirror of
https://github.com/postgresml/pgcat.git
synced 2026-03-23 01:16:30 +00:00
Add dns_cache for server addresses as in pgbouncer (#249)
* Add dns_cache so server addresses are cached and invalidated when DNS changes. Adds a module to deal with dns_cache feature. It's main struct is CachedResolver, which is a simple thread safe hostname <-> Ips cache with the ability to refresh resolutions every `dns_max_ttl` seconds. This way, a client can check whether its ip address has changed. * Allow reloading dns cached * Add documentation for dns_cached
This commit is contained in:
Jose Fernández
16
CONFIG.md
16
CONFIG.md
@@ -188,6 +188,22 @@ default: "admin_pass"
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|
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Password to access the virtual administrative database
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|
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### dns_cache_enabled
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```
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path: general.dns_cache_enabled
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default: false
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```
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When enabled, ip resolutions for server connections specified using hostnames will be cached
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and checked for changes every `dns_max_ttl` seconds. If a change in the host resolution is found
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old ip connections are closed (gracefully) and new connections will start using new ip.
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### dns_max_ttl
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```
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path: general.dns_max_ttl
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default: 30
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```
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Specifies how often (in seconds) cached ip addresses for servers are rechecked (see `dns_cache_enabled`).
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## `pools.<pool_name>` Section
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### pool_mode
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288
Cargo.lock
generated
288
Cargo.lock
generated
@@ -26,6 +26,27 @@ version = "1.6.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "bddcadddf5e9015d310179a59bb28c4d4b9920ad0f11e8e14dbadf654890c9a6"
|
||||
|
||||
[[package]]
|
||||
name = "async-stream"
|
||||
version = "0.3.3"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
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||||
checksum = "dad5c83079eae9969be7fadefe640a1c566901f05ff91ab221de4b6f68d9507e"
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dependencies = [
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"async-stream-impl",
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"futures-core",
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]
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[[package]]
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name = "async-stream-impl"
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version = "0.3.3"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "10f203db73a71dfa2fb6dd22763990fa26f3d2625a6da2da900d23b87d26be27"
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dependencies = [
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"proc-macro2",
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"quote",
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"syn 1.0.109",
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]
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[[package]]
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name = "async-trait"
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version = "0.1.68"
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@@ -212,6 +233,12 @@ dependencies = [
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"syn 1.0.109",
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]
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[[package]]
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name = "data-encoding"
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version = "2.3.2"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "3ee2393c4a91429dffb4bedf19f4d6abf27d8a732c8ce4980305d782e5426d57"
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[[package]]
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name = "digest"
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version = "0.10.6"
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@@ -223,6 +250,18 @@ dependencies = [
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"subtle",
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]
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[[package]]
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name = "enum-as-inner"
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version = "0.5.1"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "c9720bba047d567ffc8a3cba48bf19126600e249ab7f128e9233e6376976a116"
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dependencies = [
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"heck",
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"proc-macro2",
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"quote",
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"syn 1.0.109",
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]
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[[package]]
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name = "env_logger"
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version = "0.10.0"
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@@ -275,6 +314,15 @@ version = "1.0.7"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
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[[package]]
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name = "form_urlencoded"
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version = "1.1.0"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "a9c384f161156f5260c24a097c56119f9be8c798586aecc13afbcbe7b7e26bf8"
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dependencies = [
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"percent-encoding",
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]
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[[package]]
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name = "futures"
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version = "0.3.28"
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@@ -410,6 +458,12 @@ version = "0.12.3"
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "8a9ee70c43aaf417c914396645a0fa852624801b24ebb7ae78fe8272889ac888"
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|
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[[package]]
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name = "heck"
|
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version = "0.4.0"
|
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "2540771e65fc8cb83cd6e8a237f70c319bd5c29f78ed1084ba5d50eeac86f7f9"
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|
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[[package]]
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name = "hermit-abi"
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version = "0.2.6"
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@@ -434,6 +488,17 @@ dependencies = [
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"digest",
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]
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[[package]]
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name = "hostname"
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version = "0.3.1"
|
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source = "registry+https://github.com/rust-lang/crates.io-index"
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checksum = "3c731c3e10504cc8ed35cfe2f1db4c9274c3d35fa486e3b31df46f068ef3e867"
|
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dependencies = [
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"libc",
|
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"match_cfg",
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"winapi",
|
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]
|
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|
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[[package]]
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name = "http"
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version = "0.2.9"
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@@ -522,6 +587,27 @@ dependencies = [
|
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"cxx-build",
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]
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||||
|
||||
[[package]]
|
||||
name = "idna"
|
||||
version = "0.2.3"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "418a0a6fab821475f634efe3ccc45c013f742efe03d853e8d3355d5cb850ecf8"
|
||||
dependencies = [
|
||||
"matches",
|
||||
"unicode-bidi",
|
||||
"unicode-normalization",
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]
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||||
|
||||
[[package]]
|
||||
name = "idna"
|
||||
version = "0.3.0"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "e14ddfc70884202db2244c223200c204c2bda1bc6e0998d11b5e024d657209e6"
|
||||
dependencies = [
|
||||
"unicode-bidi",
|
||||
"unicode-normalization",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "indexmap"
|
||||
version = "1.9.2"
|
||||
@@ -542,6 +628,24 @@ dependencies = [
|
||||
"windows-sys",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "ipconfig"
|
||||
version = "0.3.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "bd302af1b90f2463a98fa5ad469fc212c8e3175a41c3068601bfa2727591c5be"
|
||||
dependencies = [
|
||||
"socket2",
|
||||
"widestring",
|
||||
"winapi",
|
||||
"winreg",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "ipnet"
|
||||
version = "2.5.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "f88c5561171189e69df9d98bcf18fd5f9558300f7ea7b801eb8a0fd748bd8745"
|
||||
|
||||
[[package]]
|
||||
name = "is-terminal"
|
||||
version = "0.4.4"
|
||||
@@ -589,6 +693,12 @@ dependencies = [
|
||||
"wasm-bindgen",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "lazy_static"
|
||||
version = "1.4.0"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
|
||||
|
||||
[[package]]
|
||||
name = "libc"
|
||||
version = "0.2.139"
|
||||
@@ -604,6 +714,12 @@ dependencies = [
|
||||
"cc",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "linked-hash-map"
|
||||
version = "0.5.6"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "0717cef1bc8b636c6e1c1bbdefc09e6322da8a9321966e8928ef80d20f7f770f"
|
||||
|
||||
[[package]]
|
||||
name = "linux-raw-sys"
|
||||
version = "0.1.4"
|
||||
@@ -629,6 +745,27 @@ dependencies = [
|
||||
"cfg-if",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "lru-cache"
|
||||
version = "0.1.2"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "31e24f1ad8321ca0e8a1e0ac13f23cb668e6f5466c2c57319f6a5cf1cc8e3b1c"
|
||||
dependencies = [
|
||||
"linked-hash-map",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "match_cfg"
|
||||
version = "0.1.0"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "ffbee8634e0d45d258acb448e7eaab3fce7a0a467395d4d9f228e3c1f01fb2e4"
|
||||
|
||||
[[package]]
|
||||
name = "matches"
|
||||
version = "0.1.9"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "a3e378b66a060d48947b590737b30a1be76706c8dd7b8ba0f2fe3989c68a853f"
|
||||
|
||||
[[package]]
|
||||
name = "md-5"
|
||||
version = "0.10.5"
|
||||
@@ -737,6 +874,12 @@ dependencies = [
|
||||
"windows-sys",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "percent-encoding"
|
||||
version = "2.2.0"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "478c572c3d73181ff3c2539045f6eb99e5491218eae919370993b890cdbdd98e"
|
||||
|
||||
[[package]]
|
||||
name = "pgcat"
|
||||
version = "1.0.1"
|
||||
@@ -777,7 +920,9 @@ dependencies = [
|
||||
"stringprep",
|
||||
"tokio",
|
||||
"tokio-rustls",
|
||||
"tokio-test",
|
||||
"toml",
|
||||
"trust-dns-resolver",
|
||||
"webpki-roots",
|
||||
]
|
||||
|
||||
@@ -888,6 +1033,12 @@ dependencies = [
|
||||
"unicode-ident",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "quick-error"
|
||||
version = "1.2.3"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
|
||||
|
||||
[[package]]
|
||||
name = "quote"
|
||||
version = "1.0.26"
|
||||
@@ -953,6 +1104,16 @@ version = "0.7.0"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "b6868896879ba532248f33598de5181522d8b3d9d724dfd230911e1a7d4822f5"
|
||||
|
||||
[[package]]
|
||||
name = "resolv-conf"
|
||||
version = "0.7.0"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "52e44394d2086d010551b14b53b1f24e31647570cd1deb0379e2c21b329aba00"
|
||||
dependencies = [
|
||||
"hostname",
|
||||
"quick-error",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "ring"
|
||||
version = "0.16.20"
|
||||
@@ -1191,6 +1352,26 @@ dependencies = [
|
||||
"winapi-util",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "thiserror"
|
||||
version = "1.0.37"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "10deb33631e3c9018b9baf9dcbbc4f737320d2b576bac10f6aefa048fa407e3e"
|
||||
dependencies = [
|
||||
"thiserror-impl",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "thiserror-impl"
|
||||
version = "1.0.37"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "982d17546b47146b28f7c22e3d08465f6b8903d0ea13c1660d9d84a6e7adcdbb"
|
||||
dependencies = [
|
||||
"proc-macro2",
|
||||
"quote",
|
||||
"syn 1.0.109",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "time"
|
||||
version = "0.1.45"
|
||||
@@ -1258,6 +1439,30 @@ dependencies = [
|
||||
"tokio",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "tokio-stream"
|
||||
version = "0.1.11"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "d660770404473ccd7bc9f8b28494a811bc18542b915c0855c51e8f419d5223ce"
|
||||
dependencies = [
|
||||
"futures-core",
|
||||
"pin-project-lite",
|
||||
"tokio",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "tokio-test"
|
||||
version = "0.4.2"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "53474327ae5e166530d17f2d956afcb4f8a004de581b3cae10f12006bc8163e3"
|
||||
dependencies = [
|
||||
"async-stream",
|
||||
"bytes",
|
||||
"futures-core",
|
||||
"tokio",
|
||||
"tokio-stream",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "tokio-util"
|
||||
version = "0.7.7"
|
||||
@@ -1320,9 +1525,21 @@ checksum = "8ce8c33a8d48bd45d624a6e523445fd21ec13d3653cd51f681abf67418f54eb8"
|
||||
dependencies = [
|
||||
"cfg-if",
|
||||
"pin-project-lite",
|
||||
"tracing-attributes",
|
||||
"tracing-core",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "tracing-attributes"
|
||||
version = "0.1.23"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "4017f8f45139870ca7e672686113917c71c7a6e02d4924eda67186083c03081a"
|
||||
dependencies = [
|
||||
"proc-macro2",
|
||||
"quote",
|
||||
"syn 1.0.109",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "tracing-core"
|
||||
version = "0.1.30"
|
||||
@@ -1332,6 +1549,51 @@ dependencies = [
|
||||
"once_cell",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "trust-dns-proto"
|
||||
version = "0.22.0"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "4f7f83d1e4a0e4358ac54c5c3681e5d7da5efc5a7a632c90bb6d6669ddd9bc26"
|
||||
dependencies = [
|
||||
"async-trait",
|
||||
"cfg-if",
|
||||
"data-encoding",
|
||||
"enum-as-inner",
|
||||
"futures-channel",
|
||||
"futures-io",
|
||||
"futures-util",
|
||||
"idna 0.2.3",
|
||||
"ipnet",
|
||||
"lazy_static",
|
||||
"rand",
|
||||
"smallvec",
|
||||
"thiserror",
|
||||
"tinyvec",
|
||||
"tokio",
|
||||
"tracing",
|
||||
"url",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "trust-dns-resolver"
|
||||
version = "0.22.0"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "aff21aa4dcefb0a1afbfac26deb0adc93888c7d295fb63ab273ef276ba2b7cfe"
|
||||
dependencies = [
|
||||
"cfg-if",
|
||||
"futures-util",
|
||||
"ipconfig",
|
||||
"lazy_static",
|
||||
"lru-cache",
|
||||
"parking_lot",
|
||||
"resolv-conf",
|
||||
"smallvec",
|
||||
"thiserror",
|
||||
"tokio",
|
||||
"tracing",
|
||||
"trust-dns-proto",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "try-lock"
|
||||
version = "0.2.4"
|
||||
@@ -1377,6 +1639,17 @@ version = "0.7.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "a156c684c91ea7d62626509bce3cb4e1d9ed5c4d978f7b4352658f96a4c26b4a"
|
||||
|
||||
[[package]]
|
||||
name = "url"
|
||||
version = "2.3.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "0d68c799ae75762b8c3fe375feb6600ef5602c883c5d21eb51c09f22b83c4643"
|
||||
dependencies = [
|
||||
"form_urlencoded",
|
||||
"idna 0.3.0",
|
||||
"percent-encoding",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "version_check"
|
||||
version = "0.9.4"
|
||||
@@ -1478,6 +1751,12 @@ dependencies = [
|
||||
"rustls-webpki",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "widestring"
|
||||
version = "0.5.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "17882f045410753661207383517a6f62ec3dbeb6a4ed2acce01f0728238d1983"
|
||||
|
||||
[[package]]
|
||||
name = "winapi"
|
||||
version = "0.3.9"
|
||||
@@ -1583,3 +1862,12 @@ checksum = "faf09497b8f8b5ac5d3bb4d05c0a99be20f26fd3d5f2db7b0716e946d5103658"
|
||||
dependencies = [
|
||||
"memchr",
|
||||
]
|
||||
|
||||
[[package]]
|
||||
name = "winreg"
|
||||
version = "0.10.1"
|
||||
source = "registry+https://github.com/rust-lang/crates.io-index"
|
||||
checksum = "80d0f4e272c85def139476380b12f9ac60926689dd2e01d4923222f40580869d"
|
||||
dependencies = [
|
||||
"winapi",
|
||||
]
|
||||
|
||||
@@ -42,6 +42,8 @@ fallible-iterator = "0.2"
|
||||
pin-project = "1"
|
||||
webpki-roots = "0.23"
|
||||
rustls = { version = "0.21", features = ["dangerous_configuration"] }
|
||||
trust-dns-resolver = "0.22.0"
|
||||
tokio-test = "0.4.2"
|
||||
|
||||
[target.'cfg(not(target_env = "msvc"))'.dependencies]
|
||||
jemallocator = "0.5.0"
|
||||
|
||||
@@ -146,6 +146,14 @@ idle_timeout = 40000
|
||||
# Connect timeout can be overwritten in the pool
|
||||
connect_timeout = 3000
|
||||
|
||||
# When enabled, ip resolutions for server connections specified using hostnames will be cached
|
||||
# and checked for changes every `dns_max_ttl` seconds. If a change in the host resolution is found
|
||||
# old ip connections are closed (gracefully) and new connections will start using new ip.
|
||||
# dns_cache_enabled = false
|
||||
|
||||
# Specifies how often (in seconds) cached ip addresses for servers are rechecked (see `dns_cache_enabled`).
|
||||
# dns_max_ttl = 30
|
||||
|
||||
# User configs are structured as pool.<pool_name>.users.<user_index>
|
||||
# This section holds the credentials for users that may connect to this cluster
|
||||
[pools.sharded_db.users.0]
|
||||
|
||||
@@ -12,6 +12,7 @@ use std::sync::Arc;
|
||||
use tokio::fs::File;
|
||||
use tokio::io::AsyncReadExt;
|
||||
|
||||
use crate::dns_cache::CachedResolver;
|
||||
use crate::errors::Error;
|
||||
use crate::pool::{ClientServerMap, ConnectionPool};
|
||||
use crate::sharding::ShardingFunction;
|
||||
@@ -255,6 +256,12 @@ pub struct General {
|
||||
#[serde(default)] // False
|
||||
pub log_client_disconnections: bool,
|
||||
|
||||
#[serde(default)] // False
|
||||
pub dns_cache_enabled: bool,
|
||||
|
||||
#[serde(default = "General::default_dns_max_ttl")]
|
||||
pub dns_max_ttl: u64,
|
||||
|
||||
#[serde(default = "General::default_shutdown_timeout")]
|
||||
pub shutdown_timeout: u64,
|
||||
|
||||
@@ -336,6 +343,10 @@ impl General {
|
||||
60000
|
||||
}
|
||||
|
||||
pub fn default_dns_max_ttl() -> u64 {
|
||||
30
|
||||
}
|
||||
|
||||
pub fn default_healthcheck_timeout() -> u64 {
|
||||
1000
|
||||
}
|
||||
@@ -378,6 +389,8 @@ impl Default for General {
|
||||
log_client_connections: false,
|
||||
log_client_disconnections: false,
|
||||
autoreload: None,
|
||||
dns_cache_enabled: false,
|
||||
dns_max_ttl: Self::default_dns_max_ttl(),
|
||||
tls_certificate: None,
|
||||
tls_private_key: None,
|
||||
server_tls: false,
|
||||
@@ -1119,6 +1132,10 @@ pub async fn reload_config(client_server_map: ClientServerMap) -> Result<bool, E
|
||||
}
|
||||
};
|
||||
let new_config = get_config();
|
||||
match CachedResolver::from_config().await {
|
||||
Ok(_) => (),
|
||||
Err(err) => error!("DNS cache reinitialization error: {:?}", err),
|
||||
};
|
||||
|
||||
if old_config.pools != new_config.pools {
|
||||
info!("Pool configuration changed");
|
||||
|
||||
410
src/dns_cache.rs
Normal file
410
src/dns_cache.rs
Normal file
@@ -0,0 +1,410 @@
|
||||
use crate::config::get_config;
|
||||
use crate::errors::Error;
|
||||
use arc_swap::ArcSwap;
|
||||
use log::{debug, error, info, warn};
|
||||
use once_cell::sync::Lazy;
|
||||
use std::collections::{HashMap, HashSet};
|
||||
use std::io;
|
||||
use std::net::IpAddr;
|
||||
use std::sync::Arc;
|
||||
use std::sync::RwLock;
|
||||
use tokio::time::{sleep, Duration};
|
||||
use trust_dns_resolver::error::{ResolveError, ResolveResult};
|
||||
use trust_dns_resolver::lookup_ip::LookupIp;
|
||||
use trust_dns_resolver::TokioAsyncResolver;
|
||||
|
||||
/// Cached Resolver Globally available
|
||||
pub static CACHED_RESOLVER: Lazy<ArcSwap<CachedResolver>> =
|
||||
Lazy::new(|| ArcSwap::from_pointee(CachedResolver::default()));
|
||||
|
||||
// Ip addressed are returned as a set of addresses
|
||||
// so we can compare.
|
||||
#[derive(Clone, PartialEq, Debug)]
|
||||
pub struct AddrSet {
|
||||
set: HashSet<IpAddr>,
|
||||
}
|
||||
|
||||
impl AddrSet {
|
||||
fn new() -> AddrSet {
|
||||
AddrSet {
|
||||
set: HashSet::new(),
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl From<LookupIp> for AddrSet {
|
||||
fn from(lookup_ip: LookupIp) -> Self {
|
||||
let mut addr_set = AddrSet::new();
|
||||
for address in lookup_ip.iter() {
|
||||
addr_set.set.insert(address);
|
||||
}
|
||||
addr_set
|
||||
}
|
||||
}
|
||||
|
||||
///
|
||||
/// A CachedResolver is a DNS resolution cache mechanism with customizable expiration time.
|
||||
///
|
||||
/// The system works as follows:
|
||||
///
|
||||
/// When a host is to be resolved, if we have not resolved it before, a new resolution is
|
||||
/// executed and stored in the internal cache. Concurrently, every `dns_max_ttl` time, the
|
||||
/// cache is refreshed.
|
||||
///
|
||||
/// # Example:
|
||||
///
|
||||
/// ```
|
||||
/// use pgcat::dns_cache::{CachedResolverConfig, CachedResolver};
|
||||
///
|
||||
/// # tokio_test::block_on(async {
|
||||
/// let config = CachedResolverConfig::default();
|
||||
/// let resolver = CachedResolver::new(config, None).await.unwrap();
|
||||
/// let addrset = resolver.lookup_ip("www.example.com.").await.unwrap();
|
||||
/// # })
|
||||
/// ```
|
||||
///
|
||||
/// // Now the ip resolution is stored in local cache and subsequent
|
||||
/// // calls will be returned from cache. Also, the cache is refreshed
|
||||
/// // and updated every 10 seconds.
|
||||
///
|
||||
/// // You can now check if an 'old' lookup differs from what it's currently
|
||||
/// // store in cache by using `has_changed`.
|
||||
/// resolver.has_changed("www.example.com.", addrset)
|
||||
#[derive(Default)]
|
||||
pub struct CachedResolver {
|
||||
// The configuration of the cached_resolver.
|
||||
config: CachedResolverConfig,
|
||||
|
||||
// This is the hash that contains the hash.
|
||||
data: Option<RwLock<HashMap<String, AddrSet>>>,
|
||||
|
||||
// The resolver to be used for DNS queries.
|
||||
resolver: Option<TokioAsyncResolver>,
|
||||
|
||||
// The RefreshLoop
|
||||
refresh_loop: RwLock<Option<tokio::task::JoinHandle<()>>>,
|
||||
}
|
||||
|
||||
///
|
||||
/// Configuration
|
||||
#[derive(Clone, Debug, Default, PartialEq)]
|
||||
pub struct CachedResolverConfig {
|
||||
/// Amount of time in secods that a resolved dns address is considered stale.
|
||||
dns_max_ttl: u64,
|
||||
|
||||
/// Enabled or disabled? (this is so we can reload config)
|
||||
enabled: bool,
|
||||
}
|
||||
|
||||
impl CachedResolverConfig {
|
||||
fn new(dns_max_ttl: u64, enabled: bool) -> Self {
|
||||
CachedResolverConfig {
|
||||
dns_max_ttl,
|
||||
enabled,
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
impl From<crate::config::Config> for CachedResolverConfig {
|
||||
fn from(config: crate::config::Config) -> Self {
|
||||
CachedResolverConfig::new(config.general.dns_max_ttl, config.general.dns_cache_enabled)
|
||||
}
|
||||
}
|
||||
|
||||
impl CachedResolver {
|
||||
///
|
||||
/// Returns a new Arc<CachedResolver> based on passed configuration.
|
||||
/// It also starts the loop that will refresh cache entries.
|
||||
///
|
||||
/// # Arguments:
|
||||
///
|
||||
/// * `config` - The `CachedResolverConfig` to be used to create the resolver.
|
||||
///
|
||||
/// # Example:
|
||||
///
|
||||
/// ```
|
||||
/// use pgcat::dns_cache::{CachedResolverConfig, CachedResolver};
|
||||
///
|
||||
/// # tokio_test::block_on(async {
|
||||
/// let config = CachedResolverConfig::default();
|
||||
/// let resolver = CachedResolver::new(config, None).await.unwrap();
|
||||
/// # })
|
||||
/// ```
|
||||
///
|
||||
pub async fn new(
|
||||
config: CachedResolverConfig,
|
||||
data: Option<HashMap<String, AddrSet>>,
|
||||
) -> Result<Arc<Self>, io::Error> {
|
||||
// Construct a new Resolver with default configuration options
|
||||
let resolver = Some(TokioAsyncResolver::tokio_from_system_conf()?);
|
||||
|
||||
let data = if let Some(hash) = data {
|
||||
Some(RwLock::new(hash))
|
||||
} else {
|
||||
Some(RwLock::new(HashMap::new()))
|
||||
};
|
||||
|
||||
let instance = Arc::new(Self {
|
||||
config,
|
||||
resolver,
|
||||
data,
|
||||
refresh_loop: RwLock::new(None),
|
||||
});
|
||||
|
||||
if instance.enabled() {
|
||||
info!("Scheduling DNS refresh loop");
|
||||
let refresh_loop = tokio::task::spawn({
|
||||
let instance = instance.clone();
|
||||
async move {
|
||||
instance.refresh_dns_entries_loop().await;
|
||||
}
|
||||
});
|
||||
*(instance.refresh_loop.write().unwrap()) = Some(refresh_loop);
|
||||
}
|
||||
|
||||
Ok(instance)
|
||||
}
|
||||
|
||||
pub fn enabled(&self) -> bool {
|
||||
self.config.enabled
|
||||
}
|
||||
|
||||
// Schedules the refresher
|
||||
async fn refresh_dns_entries_loop(&self) {
|
||||
let resolver = TokioAsyncResolver::tokio_from_system_conf().unwrap();
|
||||
let interval = Duration::from_secs(self.config.dns_max_ttl);
|
||||
loop {
|
||||
debug!("Begin refreshing cached DNS addresses.");
|
||||
// To minimize the time we hold the lock, we first create
|
||||
// an array with keys.
|
||||
let mut hostnames: Vec<String> = Vec::new();
|
||||
{
|
||||
if let Some(ref data) = self.data {
|
||||
for hostname in data.read().unwrap().keys() {
|
||||
hostnames.push(hostname.clone());
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
for hostname in hostnames.iter() {
|
||||
let addrset = self
|
||||
.fetch_from_cache(hostname.as_str())
|
||||
.expect("Could not obtain expected address from cache, this should not happen");
|
||||
|
||||
match resolver.lookup_ip(hostname).await {
|
||||
Ok(lookup_ip) => {
|
||||
let new_addrset = AddrSet::from(lookup_ip);
|
||||
debug!(
|
||||
"Obtained address for host ({}) -> ({:?})",
|
||||
hostname, new_addrset
|
||||
);
|
||||
|
||||
if addrset != new_addrset {
|
||||
debug!(
|
||||
"Addr changed from {:?} to {:?} updating cache.",
|
||||
addrset, new_addrset
|
||||
);
|
||||
self.store_in_cache(hostname, new_addrset);
|
||||
}
|
||||
}
|
||||
Err(err) => {
|
||||
error!(
|
||||
"There was an error trying to resolv {}: ({}).",
|
||||
hostname, err
|
||||
);
|
||||
}
|
||||
}
|
||||
}
|
||||
debug!("Finished refreshing cached DNS addresses.");
|
||||
sleep(interval).await;
|
||||
}
|
||||
}
|
||||
|
||||
/// Returns a `AddrSet` given the specified hostname.
|
||||
///
|
||||
/// This method first tries to fetch the value from the cache, if it misses
|
||||
/// then it is resolved and stored in the cache. TTL from records is ignored.
|
||||
///
|
||||
/// # Arguments
|
||||
///
|
||||
/// * `host` - A string slice referencing the hostname to be resolved.
|
||||
///
|
||||
/// # Example:
|
||||
///
|
||||
/// ```
|
||||
/// use pgcat::dns_cache::{CachedResolverConfig, CachedResolver};
|
||||
///
|
||||
/// # tokio_test::block_on(async {
|
||||
/// let config = CachedResolverConfig::default();
|
||||
/// let resolver = CachedResolver::new(config, None).await.unwrap();
|
||||
/// let response = resolver.lookup_ip("www.google.com.");
|
||||
/// # })
|
||||
/// ```
|
||||
///
|
||||
pub async fn lookup_ip(&self, host: &str) -> ResolveResult<AddrSet> {
|
||||
debug!("Lookup up {} in cache", host);
|
||||
match self.fetch_from_cache(host) {
|
||||
Some(addr_set) => {
|
||||
debug!("Cache hit!");
|
||||
Ok(addr_set)
|
||||
}
|
||||
None => {
|
||||
debug!("Not found, executing a dns query!");
|
||||
if let Some(ref resolver) = self.resolver {
|
||||
let addr_set = AddrSet::from(resolver.lookup_ip(host).await?);
|
||||
debug!("Obtained: {:?}", addr_set);
|
||||
self.store_in_cache(host, addr_set.clone());
|
||||
Ok(addr_set)
|
||||
} else {
|
||||
Err(ResolveError::from("No resolver available"))
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
//
|
||||
// Returns true if the stored host resolution differs from the AddrSet passed.
|
||||
pub fn has_changed(&self, host: &str, addr_set: &AddrSet) -> bool {
|
||||
if let Some(fetched_addr_set) = self.fetch_from_cache(host) {
|
||||
return fetched_addr_set != *addr_set;
|
||||
}
|
||||
false
|
||||
}
|
||||
|
||||
// Fetches an AddrSet from the inner cache adquiring the read lock.
|
||||
fn fetch_from_cache(&self, key: &str) -> Option<AddrSet> {
|
||||
if let Some(ref hash) = self.data {
|
||||
if let Some(addr_set) = hash.read().unwrap().get(key) {
|
||||
return Some(addr_set.clone());
|
||||
}
|
||||
}
|
||||
None
|
||||
}
|
||||
|
||||
// Sets up the global CACHED_RESOLVER static variable so we can globally use DNS
|
||||
// cache.
|
||||
pub async fn from_config() -> Result<(), Error> {
|
||||
let cached_resolver = CACHED_RESOLVER.load();
|
||||
let desired_config = CachedResolverConfig::from(get_config());
|
||||
|
||||
if cached_resolver.config != desired_config {
|
||||
if let Some(ref refresh_loop) = *(cached_resolver.refresh_loop.write().unwrap()) {
|
||||
warn!("Killing Dnscache refresh loop as its configuration is being reloaded");
|
||||
refresh_loop.abort()
|
||||
}
|
||||
let new_resolver = if let Some(ref data) = cached_resolver.data {
|
||||
let data = Some(data.read().unwrap().clone());
|
||||
CachedResolver::new(desired_config, data).await
|
||||
} else {
|
||||
CachedResolver::new(desired_config, None).await
|
||||
};
|
||||
|
||||
match new_resolver {
|
||||
Ok(ok) => {
|
||||
CACHED_RESOLVER.store(ok);
|
||||
Ok(())
|
||||
}
|
||||
Err(err) => {
|
||||
let message = format!("Error setting up cached_resolver. Error: {:?}, will continue without this feature.", err);
|
||||
Err(Error::DNSCachedError(message))
|
||||
}
|
||||
}
|
||||
} else {
|
||||
Ok(())
|
||||
}
|
||||
}
|
||||
|
||||
// Stores the AddrSet in cache adquiring the write lock.
|
||||
fn store_in_cache(&self, host: &str, addr_set: AddrSet) {
|
||||
if let Some(ref data) = self.data {
|
||||
data.write().unwrap().insert(host.to_string(), addr_set);
|
||||
} else {
|
||||
error!("Could not insert, Hash not initialized");
|
||||
}
|
||||
}
|
||||
}
|
||||
#[cfg(test)]
|
||||
mod tests {
|
||||
use super::*;
|
||||
use trust_dns_resolver::error::ResolveError;
|
||||
|
||||
#[tokio::test]
|
||||
async fn new() {
|
||||
let config = CachedResolverConfig {
|
||||
dns_max_ttl: 10,
|
||||
enabled: true,
|
||||
};
|
||||
let resolver = CachedResolver::new(config, None).await;
|
||||
assert!(resolver.is_ok());
|
||||
}
|
||||
|
||||
#[tokio::test]
|
||||
async fn lookup_ip() {
|
||||
let config = CachedResolverConfig {
|
||||
dns_max_ttl: 10,
|
||||
enabled: true,
|
||||
};
|
||||
let resolver = CachedResolver::new(config, None).await.unwrap();
|
||||
let response = resolver.lookup_ip("www.google.com.").await;
|
||||
assert!(response.is_ok());
|
||||
}
|
||||
|
||||
#[tokio::test]
|
||||
async fn has_changed() {
|
||||
let config = CachedResolverConfig {
|
||||
dns_max_ttl: 10,
|
||||
enabled: true,
|
||||
};
|
||||
let resolver = CachedResolver::new(config, None).await.unwrap();
|
||||
let hostname = "www.google.com.";
|
||||
let response = resolver.lookup_ip(hostname).await;
|
||||
let addr_set = response.unwrap();
|
||||
assert!(!resolver.has_changed(hostname, &addr_set));
|
||||
}
|
||||
|
||||
#[tokio::test]
|
||||
async fn unknown_host() {
|
||||
let config = CachedResolverConfig {
|
||||
dns_max_ttl: 10,
|
||||
enabled: true,
|
||||
};
|
||||
let resolver = CachedResolver::new(config, None).await.unwrap();
|
||||
let hostname = "www.idontexists.";
|
||||
let response = resolver.lookup_ip(hostname).await;
|
||||
assert!(matches!(response, Err(ResolveError { .. })));
|
||||
}
|
||||
|
||||
#[tokio::test]
|
||||
async fn incorrect_address() {
|
||||
let config = CachedResolverConfig {
|
||||
dns_max_ttl: 10,
|
||||
enabled: true,
|
||||
};
|
||||
let resolver = CachedResolver::new(config, None).await.unwrap();
|
||||
let hostname = "w ww.idontexists.";
|
||||
let response = resolver.lookup_ip(hostname).await;
|
||||
assert!(matches!(response, Err(ResolveError { .. })));
|
||||
assert!(!resolver.has_changed(hostname, &AddrSet::new()));
|
||||
}
|
||||
|
||||
#[tokio::test]
|
||||
// Ok, this test is based on the fact that google does DNS RR
|
||||
// and does not responds with every available ip everytime, so
|
||||
// if I cache here, it will miss after one cache iteration or two.
|
||||
async fn thread() {
|
||||
let config = CachedResolverConfig {
|
||||
dns_max_ttl: 10,
|
||||
enabled: true,
|
||||
};
|
||||
let resolver = CachedResolver::new(config, None).await.unwrap();
|
||||
let hostname = "www.google.com.";
|
||||
let response = resolver.lookup_ip(hostname).await;
|
||||
let addr_set = response.unwrap();
|
||||
assert!(!resolver.has_changed(hostname, &addr_set));
|
||||
let resolver_for_refresher = resolver.clone();
|
||||
let _thread_handle = tokio::task::spawn(async move {
|
||||
resolver_for_refresher.refresh_dns_entries_loop().await;
|
||||
});
|
||||
assert!(!resolver.has_changed(hostname, &addr_set));
|
||||
}
|
||||
}
|
||||
@@ -19,6 +19,7 @@ pub enum Error {
|
||||
ClientError(String),
|
||||
TlsError,
|
||||
StatementTimeout,
|
||||
DNSCachedError(String),
|
||||
ShuttingDown,
|
||||
ParseBytesError(String),
|
||||
AuthError(String),
|
||||
|
||||
@@ -1,6 +1,7 @@
|
||||
pub mod auth_passthrough;
|
||||
pub mod config;
|
||||
pub mod constants;
|
||||
pub mod dns_cache;
|
||||
pub mod errors;
|
||||
pub mod messages;
|
||||
pub mod mirrors;
|
||||
|
||||
@@ -36,6 +36,7 @@ extern crate sqlparser;
|
||||
extern crate tokio;
|
||||
extern crate tokio_rustls;
|
||||
extern crate toml;
|
||||
extern crate trust_dns_resolver;
|
||||
|
||||
#[cfg(not(target_env = "msvc"))]
|
||||
use jemallocator::Jemalloc;
|
||||
@@ -65,6 +66,7 @@ mod auth_passthrough;
|
||||
mod client;
|
||||
mod config;
|
||||
mod constants;
|
||||
mod dns_cache;
|
||||
mod errors;
|
||||
mod messages;
|
||||
mod mirrors;
|
||||
@@ -166,6 +168,12 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
|
||||
// Statistics reporting.
|
||||
REPORTER.store(Arc::new(Reporter::default()));
|
||||
|
||||
// Starts (if enabled) dns cache before pools initialization
|
||||
match dns_cache::CachedResolver::from_config().await {
|
||||
Ok(_) => (),
|
||||
Err(err) => error!("DNS cache initialization error: {:?}", err),
|
||||
};
|
||||
|
||||
// Connection pool that allows to query all shards and replicas.
|
||||
match ConnectionPool::from_config(client_server_map.clone()).await {
|
||||
Ok(_) => (),
|
||||
|
||||
@@ -7,6 +7,7 @@ use parking_lot::{Mutex, RwLock};
|
||||
use postgres_protocol::message;
|
||||
use std::collections::HashMap;
|
||||
use std::io::Read;
|
||||
use std::net::IpAddr;
|
||||
use std::sync::Arc;
|
||||
use std::time::SystemTime;
|
||||
use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, BufStream};
|
||||
@@ -16,6 +17,7 @@ use tokio_rustls::{client::TlsStream, TlsConnector};
|
||||
|
||||
use crate::config::{get_config, Address, User};
|
||||
use crate::constants::*;
|
||||
use crate::dns_cache::{AddrSet, CACHED_RESOLVER};
|
||||
use crate::errors::{Error, ServerIdentifier};
|
||||
use crate::messages::*;
|
||||
use crate::mirrors::MirroringManager;
|
||||
@@ -148,6 +150,9 @@ pub struct Server {
|
||||
last_activity: SystemTime,
|
||||
|
||||
mirror_manager: Option<MirroringManager>,
|
||||
|
||||
// Associated addresses used
|
||||
addr_set: Option<AddrSet>,
|
||||
}
|
||||
|
||||
impl Server {
|
||||
@@ -161,6 +166,24 @@ impl Server {
|
||||
stats: Arc<ServerStats>,
|
||||
auth_hash: Arc<RwLock<Option<String>>>,
|
||||
) -> Result<Server, Error> {
|
||||
let cached_resolver = CACHED_RESOLVER.load();
|
||||
let mut addr_set: Option<AddrSet> = None;
|
||||
|
||||
// If we are caching addresses and hostname is not an IP
|
||||
if cached_resolver.enabled() && address.host.parse::<IpAddr>().is_err() {
|
||||
debug!("Resolving {}", &address.host);
|
||||
addr_set = match cached_resolver.lookup_ip(&address.host).await {
|
||||
Ok(ok) => {
|
||||
debug!("Obtained: {:?}", ok);
|
||||
Some(ok)
|
||||
}
|
||||
Err(err) => {
|
||||
warn!("Error trying to resolve {}, ({:?})", &address.host, err);
|
||||
None
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
let mut stream =
|
||||
match TcpStream::connect(&format!("{}:{}", &address.host, address.port)).await {
|
||||
Ok(stream) => stream,
|
||||
@@ -609,6 +632,7 @@ impl Server {
|
||||
bad: false,
|
||||
needs_cleanup: false,
|
||||
client_server_map,
|
||||
addr_set,
|
||||
connected_at: chrono::offset::Utc::now().naive_utc(),
|
||||
stats,
|
||||
application_name: String::new(),
|
||||
@@ -849,7 +873,23 @@ impl Server {
|
||||
/// Server & client are out of sync, we must discard this connection.
|
||||
/// This happens with clients that misbehave.
|
||||
pub fn is_bad(&self) -> bool {
|
||||
self.bad
|
||||
if self.bad {
|
||||
return self.bad;
|
||||
};
|
||||
let cached_resolver = CACHED_RESOLVER.load();
|
||||
if cached_resolver.enabled() {
|
||||
if let Some(addr_set) = &self.addr_set {
|
||||
if cached_resolver.has_changed(self.address.host.as_str(), addr_set) {
|
||||
warn!(
|
||||
"DNS changed for {}, it was {:?}. Dropping server connection.",
|
||||
self.address.host.as_str(),
|
||||
addr_set
|
||||
);
|
||||
return true;
|
||||
}
|
||||
}
|
||||
}
|
||||
false
|
||||
}
|
||||
|
||||
/// Get server startup information to forward it to the client.
|
||||
|
||||
Reference in New Issue
Block a user