optionnally set datadir with env var

ex: `PHOENIX_DATADIR=/my/phoenix/dir ./phoenixd`

src/commonMain/kotlin/fr/acinq/lightning/bin/Expects.kt

@@ -5,6 +5,6 @@ import fr.acinq.bitcoin.Chain
 import fr.acinq.bitcoin.PublicKey
 import okio.Path
 
-expect val homeDirectory: Path
+expect val datadir: Path
 
 expect fun createAppDbDriver(dir: Path, chain: Chain, nodeId: PublicKey): SqlDriver

src/commonMain/kotlin/fr/acinq/lightning/bin/Main.kt

@@ -68,8 +68,6 @@ fun main(args: Array<String>) = Phoenixd()
     .main(args)
 
 class Phoenixd : CliktCommand() {
-    //private val datadir by option("--datadir", help = "Data directory").convert { it.toPath() }.default(homeDirectory / ".phoenix", defaultForHelp = "~/.phoenix")
-    private val datadir = homeDirectory / ".phoenix"
     private val confFile = datadir / "phoenix.conf"
     private val chain by option("--chain", help = "Bitcoin chain to use").choice(
         "mainnet" to Chain.Mainnet, "testnet" to Chain.Testnet

src/commonMain/kotlin/fr/acinq/lightning/bin/conf/EnvVars.kt

@@ -0,0 +1,5 @@
+package fr.acinq.lightning.bin.conf
+
+object EnvVars {
+    const val PHOENIX_DATADIR = "PHOENIX_DATADIR"
+}

src/commonMain/kotlin/fr/acinq/lightning/cli/PhoenixCli.kt

@@ -14,7 +14,7 @@ import fr.acinq.bitcoin.Bech32
 import fr.acinq.bitcoin.ByteVector32
 import fr.acinq.lightning.BuildVersions
 import fr.acinq.lightning.bin.conf.readConfFile
-import fr.acinq.lightning.bin.homeDirectory
+import fr.acinq.lightning.bin.datadir
 import fr.acinq.lightning.payment.Bolt11Invoice
 import fr.acinq.lightning.utils.UUID
 import io.ktor.client.*
@@ -40,7 +40,6 @@ fun main(args: Array<String>) =
 data class HttpConf(val baseUrl: Url, val httpClient: HttpClient)
 
 class PhoenixCli : CliktCommand() {
-    private val datadir = homeDirectory / ".phoenix"
     private val confFile = datadir / "phoenix.conf"
 
     private val httpBindIp by option("--http-bind-ip", help = "Bind ip for the http api").default("127.0.0.1")

src/jvmMain/kotlin/fr/acinq/lightning/bin/Actuals.kt

@@ -4,11 +4,12 @@ import app.cash.sqldelight.db.SqlDriver
 import app.cash.sqldelight.driver.jdbc.sqlite.JdbcSqliteDriver
 import fr.acinq.bitcoin.Chain
 import fr.acinq.bitcoin.PublicKey
+import fr.acinq.lightning.bin.conf.EnvVars.PHOENIX_DATADIR
 import fr.acinq.phoenix.db.PhoenixDatabase
 import okio.Path
 import okio.Path.Companion.toPath
 
-actual val homeDirectory: Path = System.getProperty("user.home").toPath()
+actual val datadir: Path = (System.getenv()[PHOENIX_DATADIR]?.toPath() ?: System.getProperty("user.home").toPath().div(".phoenix"))
 
 actual fun createAppDbDriver(dir: Path, chain: Chain, nodeId: PublicKey): SqlDriver {
     val path = dir / "phoenix.${chain.name.lowercase()}.${nodeId.toHex().take(6)}.db"

src/nativeMain/kotlin/fr/acinq/lightning/bin/Actuals.kt

@@ -2,6 +2,7 @@ package fr.acinq.lightning.bin
 
 import app.cash.sqldelight.db.SqlDriver
 import app.cash.sqldelight.driver.native.NativeSqliteDriver
+import fr.acinq.lightning.bin.conf.EnvVars.PHOENIX_DATADIR
 import fr.acinq.phoenix.db.PhoenixDatabase
 import fr.acinq.bitcoin.Chain
 import fr.acinq.bitcoin.PublicKey
@@ -13,7 +14,9 @@ import platform.posix.getenv
 import platform.posix.setenv
 
 @OptIn(ExperimentalForeignApi::class)
-actual val homeDirectory: Path = setenv("KTOR_LOG_LEVEL", "WARN", 1).let { getenv("HOME")?.toKString()!!.toPath() }
+actual val datadir: Path = setenv("KTOR_LOG_LEVEL", "WARN", 1)
+    .let {
+        getenv(PHOENIX_DATADIR)?.toKString()?.toPath() ?: getenv("HOME")?.toKString()!!.toPath().div(".phoenix") }
 
 actual fun createAppDbDriver(dir: Path, chain: Chain, nodeId: PublicKey): SqlDriver {
     return NativeSqliteDriver(PhoenixDatabase.Schema, "phoenix.${chain.name.lowercase()}.${nodeId.toHex().take(6)}.db",