src/server.go: refactor eosio v1/v2 api code into it's own module that implements a common interface

src/api/go.mod

@@ -0,0 +1,3 @@
+module internal/api
+
+go 1.14

src/api/interface.go

@@ -0,0 +1,11 @@
+
+package api
+
+import (
+    "github.com/eosswedenorg-go/haproxy"
+)
+
+type ApiInterface interface {
+    Name() string
+    Call() (haproxy.HealthCheckStatus, string)
+}

src/api/v1.go

@@ -0,0 +1,55 @@
+
+package api
+
+import (
+    "fmt"
+    "time"
+    "github.com/eosswedenorg-go/haproxy"
+    "github.com/eosswedenorg-go/eosapi"
+)
+
+type EosioV1 struct {
+    params eosapi.ReqParams
+    block_time float64
+}
+
+func NewEosioV1(params eosapi.ReqParams, block_time float64) EosioV1 {
+    return EosioV1{
+        params: params,
+        block_time: block_time,
+    }
+}
+
+func (e EosioV1) Name() string {
+    return "v1"
+}
+
+//  check_api - Validates head block time.
+// ---------------------------------------------------------
+func (e EosioV1) Call() (haproxy.HealthCheckStatus, string) {
+
+    info, err := eosapi.GetInfo(e.params)
+    if err != nil {
+        msg := fmt.Sprintf("%s", err);
+        return haproxy.HealthCheckFailed, msg
+    }
+
+    // Check HTTP Status Code
+    if info.HTTPStatusCode > 299 {
+        return haproxy.HealthCheckDown,
+            fmt.Sprintf("Taking offline because %v was received from backend", info.HTTPStatusCode)
+    }
+
+    // Validate head block.
+    now  := time.Now().In(time.UTC)
+    diff := now.Sub(info.HeadBlockTime).Seconds()
+
+    if diff > e.block_time {
+        return haproxy.HealthCheckDown,
+            fmt.Sprintf("Taking offline because head block is lagging %.0f seconds", diff)
+    } else if diff < -e.block_time {
+        return haproxy.HealthCheckDown,
+            fmt.Sprintf("Taking offline because head block is %.0f seconds into the future", diff)
+    }
+    return haproxy.HealthCheckUp, "OK"
+}

src/api/v2.go

@@ -0,0 +1,72 @@
+
+package api
+
+import (
+    "fmt"
+    "internal/utils"
+    "github.com/eosswedenorg-go/haproxy"
+    "github.com/eosswedenorg-go/eosapi"
+)
+
+type EosioV2 struct {
+    params eosapi.ReqParams
+    offset int64
+}
+
+func NewEosioV2(params eosapi.ReqParams, offset int64) EosioV2 {
+    return EosioV2{
+        params: params,
+        offset: offset,
+    }
+}
+
+func (e EosioV2) Name() string {
+    return "v2"
+}
+
+//  check_api - Validates head block time.
+// ---------------------------------------------------------
+func (e EosioV2) Call() (haproxy.HealthCheckStatus, string) {
+
+    health, err := eosapi.GetHealth(e.params)
+    if err != nil {
+        msg := fmt.Sprintf("%s", err);
+        return haproxy.HealthCheckFailed, msg
+    }
+
+    // Check HTTP Status Code
+    if health.HTTPStatusCode > 299 {
+        return haproxy.HealthCheckDown,
+            fmt.Sprintf("Taking offline because %v was received from backend", health.HTTPStatusCode)
+    }
+
+    // Fetch elasticsearch and nodeos block numbers from json.
+    var es_block int64 = 0
+    var node_block int64 = 0
+
+    for _, v := range health.Health {
+        if v.Name == "Elasticsearch" {
+            es_block = utils.JsonGetInt64(v.Data["last_indexed_block"])
+        } else if v.Name == "NodeosRPC" {
+            node_block = utils.JsonGetInt64(v.Data["head_block_num"])
+        }
+    }
+
+    // Error out if ether or both are zero.
+    if es_block == 0 || node_block == 0 {
+        msg := fmt.Sprintf("Failed to get Elasticsearch and/or nodeos " +
+            "block numbers (es: %d, eos: %d)", es_block, node_block)
+        return haproxy.HealthCheckFailed, msg
+    }
+
+    // Check if ES is behind or in the future.
+    diff := node_block - es_block;
+    if diff > e.offset {
+        return haproxy.HealthCheckDown,
+            fmt.Sprintf("Taking offline because Elastic is %d blocks behind", diff)
+    } else if diff < -e.offset {
+        return haproxy.HealthCheckDown,
+            fmt.Sprintf("Taking offline because Elastic is %d blocks into the future", -1 * diff)
+    }
+    return haproxy.HealthCheckUp, "OK"
+}